conclusion greenhouse effect essay

Essay on Greenhouse Effect for Students and Children

500 words essay on greenhouse effect.

The past month, July of 2019, has been the hottest month in the records of human history. This means on a global scale, the average climate and temperatures are now seen a steady rise year-on-year. The culprits of this climate change phenomenon are mainly pollution , overpopulation and general disregard for the environment by the human race. However, we can specifically point to two phenomenons that contribute to the rising temperatures – global warming and the greenhouse effect. Let us see more about them in this essay on the greenhouse effect.

The earth’s surface is surrounded by an envelope of the air we call the atmosphere. Gasses in this atmosphere trap the infrared radiation of the sun which generates heat on the surface of the earth. In an ideal scenario, this effect causes the temperature on the earth to be around 15c. And without such a phenomenon life could not sustain on earth.

However, due to rapid industrialization and rising pollution, the emission of greenhouse gases has increased multifold over the last few centuries. This, in turn, causes more radiation to be trapped in the earth’s atmosphere. And as a consequence, the temperature on the surface of the planet steadily rises. This is what we refer to when we talk about the man-made greenhouse effect.

Causes of Greenhouse Effect

As we saw earlier in this essay on the greenhouse effect, the phenomenon itself is naturally occurring and an important one to sustain life on our planet. However, there is an anthropogenic part of this effect. This is caused due to the activities of man.

The most prominent among this is the burning of fossil fuels . Our industries, vehicles, factories, etc are overly reliant on fossil fuels for their energy and power. This has caused an immense increase in emissions of harmful greenhouse gasses such as carbon dioxide, carbon monoxide, sulfides, etc. This has multiplied the greenhouse effect and we have seen a steady rise in surface temperatures.

Other harmful activities such as deforestation, excessive urbanization, harmful agricultural practices, etc. have also led to the release of excess carbon dioxide and made the greenhouse effect more prominent. Another harmful element that causes harm to the environment is CFC (chlorofluorocarbon).

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Some Effects of Greenhouse Effect

Even after overwhelming proof, there are still people who deny the existence of climate change and its devastating pitfalls. However, there are so many effects and pieces of evidence of climate change it is now undeniable. The surface temperature of the planet has risen by 1c since the 19th century. This change is largely due to the increased emissions of carbon dioxide. The most harm has been seen in the past 35 years in particular.

The oceans and the seas have absorbed a lot of this increased heat. The surfaces of these oceans have seen a rise in temperatures of 0.4c. The ice sheets and glaciers are also rapidly shrinking. The rate at which the ice caps melt in Antartica has tripled in the last decade itself. These alarming statistics and facts are proof of the major disaster we face in the form of climate change.

600 Words Essay on Greenhouse Effect

A Greenhouse , as the term suggests, is a structure made of glass which is designed to trap heat inside. Thus, even on cold chilling winter days, there is warmth inside it. Similarly, Earth also traps energy from the Sun and prevents it from escaping back. The greenhouse gases or the molecules present in the atmosphere of the Earth trap the heat of the Sun. This is what we know as the Greenhouse effect.

Greenhouse Gases

These gases or molecules are naturally present in the atmosphere of the Earth. However, they are also released due to human activities. These gases play a vital role in trapping the heat of the Sun and thereby gradually warming the temperature of Earth. The Earth is habitable for humans due to the equilibrium of the energy it receives and the energy that it reflects back to space.

Global Warming and the Greenhouse Effect

The trapping and emission of radiation by the greenhouse gases present in the atmosphere is known as the Greenhouse effect. Without this process, Earth will either be very cold or very hot, which will make life impossible on Earth.

The greenhouse effect is a natural phenomenon. Due to wrong human activities such as clearing forests, burning fossil fuels, releasing industrial gas in the atmosphere, etc., the emission of greenhouse gases is increasing.

Thus, this has, in turn, resulted in global warming . We can see the effects due to these like extreme droughts, floods, hurricanes, landslides, rise in sea levels, etc. Global warming is adversely affecting our biodiversity, ecosystem and the life of the people. Also, the Himalayan glaciers are melting due to this.

There are broadly two causes of the greenhouse effect:

I. Natural Causes

Some components that are present on the Earth naturally produce greenhouse gases. For example, carbon dioxide is present in the oceans, decaying of plants due to forest fires and the manure of some animals produces methane , and nitrogen oxide is present in water and soil.
Water Vapour raises the temperature by absorbing energy when there is a rise in the humidity.
Humans and animals breathe oxygen and release carbon dioxide in the atmosphere.

II. Man-made Causes

Burning of fossil fuels such as oil and coal emits carbon dioxide in the atmosphere which causes an excessive greenhouse effect. Also, while digging a coal mine or an oil well, methane is released from the Earth, which pollutes it.
Trees with the help of the process of photosynthesis absorb the carbon dioxide and release oxygen. Due to deforestation the carbon dioxide level is continuously increasing. This is also a major cause of the increase in the greenhouse effect.
In order to get maximum yield, the farmers use artificial nitrogen in their fields. This releases nitrogen oxide in the atmosphere.
Industries release harmful gases in the atmosphere like methane, carbon dioxide , and fluorine gas. These also enhance global warming.

All the countries of the world are facing the ill effects of global warming. The Government and non-governmental organizations need to take appropriate and concrete measures to control the emission of toxic greenhouse gases. They need to promote the greater use of renewable energy and forestation. Also, it is the duty of every individual to protect the environment and not use such means that harm the atmosphere. It is the need of the hour to protect our environment else that day is not far away when life on Earth will also become difficult.

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The Greenhouse Effect and our Planet

The greenhouse effect happens when certain gases, which are known as greenhouse gases, accumulate in Earth’s atmosphere. Greenhouse gases include carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), ozone (O 3 ), and fluorinated gases.

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The greenhouse effect happens when certain gases , which are known as greenhouse gases , accumulate in Earth’s atmosphere . Greenhouse gases include carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), ozone (O 3 ), and fluorinated gases.

Greenhouse gases allow the sun’s light to shine onto Earth’s surface, and then the gases , such as ozone , trap the heat that reflects back from the surface inside Earth’s atmosphere . The gases act like the glass walls of a greenhouse —thus the name, greenhouse gas .

According to scientists, the average temperature of Earth would drop from 14˚C (57˚F) to as low as –18˚C (–0.4˚F), without the greenhouse effect .

Some greenhouse gases come from natural sources, for example, evaporation adds water vapor to the atmosphere . Animals and plants release carbon dioxide when they respire, or breathe. Methane is released naturally from decomposition. There is evidence that suggests methane is released in low-oxygen environments , such as swamps or landfills . Volcanoes —both on land and under the ocean —release greenhouse gases , so periods of high volcanic activity tend to be warmer.

Since the Industrial Revolution of the late 1700s and early 1800s, people have been releasing larger quantities of greenhouse gases into the atmosphere. That amount has skyrocketed in the past century. Greenhouse gas emissions increased 70 percent between 1970 and 2004. Emissions of CO 2 , rose by about 80 percent during that time.

The amount of CO 2 in the atmosphere far exceeds the naturally occurring range seen during the last 650,000 years.

Most of the CO 2 that people put into the atmosphere comes from burning fossil fuels . Cars, trucks, t rains , and planes all burn fossil fuels. Many electric power plants do as well. Another way humans release CO 2 into the atmosphere is by cutting down forests , because trees contain large amounts of carbon.

People add methane to the atmosphere through livestock farming, landfills , and fossil fuel production such as coal mining and natural gas processing. Nitrous oxide comes from agriculture and fossil fuel burning. Fluorinated gases include chlorofluoro carbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). They are produced during the manufacturing of refrigeration and cooling products and through aerosols.

All of these human activities add greenhouse gases to the atmosphere . As the level of these gases rises, so does the temperature of Earth. The rise in Earth’s average temperature contributed to by human activity is known as global warming .

The Greenhouse Effect and Climate Change Even slight increases in average global temperatures can have huge effects.

Perhaps the biggest, most obvious effect is that glaciers and ice caps melt faster than usual. The meltwater d rains into the oceans , causing sea levels to rise.

Glaciers and ice caps cover about 10 percent of the world’s landmasses. They hold between 70 and 75 percent of the world’s freshwater . If all of this ice melted, sea levels would rise by about 70 meters (230 feet).

The Intergovernmental Panel on Climate Change states that the global sea level rose about 1.8 millimeters (0.07 inches) per year from 1961 to 1993, and about 3.1 millimeters (0.12 inches) per year since 1993.

Rising sea levels cause flooding in coastal cities, which could displace millions of people in low-lying areas such as Bangladesh, the U.S. state of Florida, and the Netherlands.

Millions more people in countries like Bolivia, Peru, and India depend on glacial meltwater for drinking, irrigation , and hydroelectric power . Rapid loss of these glaciers would devastate those countries.

Greenhouse gas emissions affect more than just temperature . Another effect involves changes in precipitation , such as rain and snow .

Over the course of the 20th century, precipitation increased in eastern parts of North and South America, northern Europe, and northern and central Asia. However, it has decreased in parts of Africa, the Mediterranean, and southern Asia.

As climates change, so do the habitats for living things. Animals that are adapted to a certain climate may become threatened. Many human societies depend on predictable rain patterns in order to grow specific crops for food, clothing, and trade. If the climate of an area changes, the people who live there may no longer be able to grow the crops they depend on for survival. Some scientists also worry that tropical diseases will expand their ranges into what are now more temperate regions if the temperatures of those areas increase.

Most climate scientists agree that we must reduce the amount of greenhouse gases released into the atmosphere. Ways to do this, include:

driving less, using public transportation , carpooling, walking, or riding a bike.
flying less—airplanes produce huge amounts of greenhouse gas emissions.
reducing, reusing, and recycling.
planting a tree—trees absorb carbon dioxide, keeping it out of the atmosphere.
using less electricity .
eating less meat—cows are one of the biggest methane producers.
supporting alternative energy sources that don’t burn fossil fuels.

Artificial Gas

Chlorofluorocarbons (CFCs) are the only greenhouse gases not created by nature. They are created through refrigeration and aerosol cans.

CFCs, used mostly as refrigerants, are chemicals that were developed in the late 19th century and came into wide use in the mid-20th century.

Other greenhouse gases, such as carbon dioxide, are emitted by human activity, at an unnatural and unsustainable level, but the molecules do occur naturally in Earth's atmosphere.

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Related Resources

Understanding Global Change

Discover why the climate and environment changes, your place in the Earth system, and paths to a resilient future.

Greenhouse effect

Life as we know it would be impossible if not for the greenhouse effect, the process through which heat is absorbed and re-radiated in that atmosphere. The intensity of a planet’s greenhouse effect is determined by the relative abundance of greenhouse gases in its atmosphere. Without greenhouse gases, most of Earth’s heat would be lost to outer space, and our planet would quickly turn into a giant ball of ice. Increase the amount of greenhouse gases to the levels found on the planet Venus, and the Earth would be as hot as a pizza oven! Fortunately, the strength of Earth’s greenhouse effect keeps our planet within a temperature range that supports life

Global Change Infographic

The greenhouse effect occurs in the atmosphere, and is an essential part of How the Earth System Works. Click the image on the left to open the Understanding Global Change Infographic . Locate the greenhouse effect icon and identify other topics that cause changes to, or are affected by, the greenhouse effect.

Adapted from the Environmental Protection Agency greenhouse effect file

Greenhouse gases such as methane, carbon dioxide, nitrous oxide, and water vapor significantly affect the amount of energy in the Earth system, even though they make up a tiny percentage of Earth’s atmosphere. Solar radiation that passes through the atmosphere and reaches Earth’s surface is either reflected or absorbed . Reflected sunlight doesn’t add any heat to the Earth system because this energy bounces back into space.

However, absorbed sunlight increases the temperature of Earth’s surface, and the warmed surface re-radiates as long-wave radiation (also known as infrared radiation). Infrared radiation is invisible to the eye, but we feel it as heat.

If there were not any greenhouse gases in the atmosphere, all that heat would pass directly back into space. With greenhouse gases present, however, most of the long-wave radiation coming from Earth’s surface is absorbed and then re-radiated in all directions many times before passing back into space. Heat that is re-radiated downward, toward the Earth, is absorbed by the surface and re-radiated again.

Clouds also influence the greenhouse effect. A thick, low cloud cover can enhance the reflectivity of the atmosphere, reducing the amount of solar radiation reaching Earth’s surface, but clouds high in the atmosphere can intensify the greenhouse effect by re-radiating heat from the Earth’s surface.

Altogether, this cycle of absorption and re-radiation by greenhouse gases impedes the loss of heat from our atmosphere to space, creating the greenhouse effect. Increases in the amount of greenhouses gases will mean that more heat is trapped, increasing the amount of energy in the Earth system (Earth’s energy budget), and raising Earth’s temperature. This increase in Earth’s average temperature is also known as global warming.

This Earth system model is one way to represent the essential processes and interactions related to the greenhouse effect. Hover over the icons for brief explanations; click on the icons to learn more about each topic. Download the Earth system models on this page. There are a few ways that the relationships among these topics can be represented and explained using the Understanding Global Change icons ( download examples ).

The greenhouse effect, which influences Earth’s average temperature, affects many of the processes that shape global climate and ecosystems. This model shows some of the other parts of the Earth system that the greenhouse effect influences, including the water cycle and water temperature .

Humans directly affect the greenhouse effect through activities that result in greenhouse gas emissions. The Earth system model below includes some of the ways that human activities increase the amount of greenhouse gases in the atmosphere. Releasing greenhouse gases intensifies the greenhouse effect, and increases Earth’s average air temperatures (also known as global warming). Hover over or click on the icons to learn more about these human causes of change and how they influence the greenhouse effect.

Click the scene icons and bolded terms on this page to learn more about these process and phenomena.

Learn more in these real-world examples, and challenge yourself to construct a model that explains the Earth system relationships.

Ancient fossils and modern climate change
How Global Warming Works
NASA: Global Climate Change: A Blanket Around the Earth
UCAR Center for Science Education: The Greenhouse Effect
IPCC: What is the Greenhouse Effect?
Indicators of Change (NCA.2014)
Human influence on the greenhouse effect
The Carbon Cycle and Earth’s Climate

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21.1: The Greenhouse Effect and Climate Change

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Melissa Ha and Rachel Schleiger
Yuba College & Butte College via ASCCC Open Educational Resources Initiative

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Earth’s Temperature is a Balancing Act

Earth’s temperature depends on the balance between energy entering and leaving the planet. When incoming energy from the sun is absorbed, Earth warms. When the sun’s energy is reflected back into space, Earth avoids warming. When energy is released from Earth into space, the planet cools. Many factors, both natural and human, can cause changes in Earth’s energy balance, including:

Changes in the greenhouse effect, which affects the amount of heat retained by Earth’s atmosphere;
Variations in the sun’s energy reaching Earth;
Changes in the reflectivity of Earth’s atmosphere and surface.

Scientists have pieced together a picture of Earth’s climate, dating back hundreds of thousands of years, by analyzing a number of indirect measures of climate such as ice cores, tree rings, glacier size, pollen counts, and ocean sediments. Scientists have also studied changes in Earth’s orbit around the sun and the activity of the sun itself.

The historical record shows that the climate varies naturally over a wide range of time scales. In general, climate changes prior to the Industrial Revolution in the 1700s can be explained by natural causes, such as changes in solar energy, volcanic eruptions, and natural changes in greenhouse gas (GHG) concentrations. Recent changes in climate , however, cannot be explained by natural causes alone. Research indicates that natural causes are very unlikely to explain most observed warming, especially warming since the mid-20th century. Rather, human activities, especially our combustion of fossil fuels, explains the current warming (figure $\PageIndex{a}$). The scientific consensus is clear: through alterations of the carbon cycle, humans are changing the global climate by increasing the effects of something known as the greenhouse effect.

The Greenhouse Effect Causes the Atmosphere to Retain Heat

Gardeners that live in moderate or cool environments use greenhouses because they trap heat and create an environment that is warmer than outside temperatures. This is great for plants that like heat, or are sensitive to cold temperatures, such as tomato and pepper plants. Greenhouses contain glass or plastic that allow visible light from the sun to pass. This light, which is a form of energy, is absorbed by plants, soil, and surfaces and heats them. Some of that heat energy is then radiated outwards in the form of infrared radiation, a different form of energy. Unlike with visible light, the glass of the greenhouse blocks the infrared radiation, thereby trapping the heat energy, causing the temperature within the greenhouse to increase.

The same phenomenon happens inside a car on a sunny day. Have you ever noticed how much hotter a car can get compared to the outside temperature? Light energy from the sun passes through the windows and is absorbed by the surfaces in the car such as seats and the dashboard. Those warm surfaces then radiate infrared radiation, which cannot pass through the glass. This trapped infrared energy causes the air temperatures in the car to increase. This process is commonly known as the greenhouse effect .

The video below made for kids, but provides a clear and simple introduction to the greenhouse effect.

The greenhouse effect also happens with the entire Earth. Of course, our planet is not surrounded by glass windows. Instead, the Earth is wrapped with an atmosphere that contains greenhouse gases (GHGs). Much like the glass in a greenhouse, GHGs allow incoming visible light energy from the sun to pass, but they block infrared radiation that is radiated from the Earth towards space (figure $\PageIndex{b}$). In this way, they help trap heat energy that subsequently raises air temperature. Being a greenhouse gas is a physical property of certain types of gases; because of their molecular structure they absorb wavelengths of infrared radiation, but are transparent to visible light. Some notable greenhouse gases are water vapor (H 2 O), carbon dioxide (CO 2 ), and methane (CH 4 ). GHGs act like a blanket, making Earth significantly warmer than it would otherwise be. Scientists estimate that average temperature on Earth would be -18º C without naturally-occurring GHGs.

Heat from solar radiation is trapped by the atmosphere. Human activities increase greenhouse gases resulting in an enhanced greenhouse effect.

What is Global Warming?

Global warming refers to the recent and ongoing rise in global average temperature near Earth’s surface. It is caused mostly by increasing concentrations of greenhouse gases in the atmosphere. Global warming is causing climate patterns to change. However, global warming itself represents only one aspect of climate change.

What is Climate Change?

Climate change refers to any significant change in the measures of climate lasting for an extended period of time. In other words, climate change includes major changes in temperature, precipitation, or wind patterns, among other effects, that occur over several decades or longer.

The Main Greenhouse Gasses

The most important GHGs directly emitted by humans include CO 2 and methane. Carbon dioxide (CO 2 ) is the primary greenhouse gas that is contributing to recent global climate change. CO 2 is a natural component of the carbon cycle, involved in such activities as photosynthesis, respiration, volcanic eruptions, and ocean-atmosphere exchange. Human activities, primarily the burning of fossil fuels and changes in land use, release very large amounts of CO 2 to the atmosphere, causing its concentration in the atmosphere to rise.

Atmospheric CO 2 concentrations have increased by 45% since pre-industrial times, from approximately 280 parts per million (ppm) in the 18th century to 409.8 ppm in 2019 (figure $\PageIndex{c}$). The current CO 2 level is higher than it has been in at least 800,000 years, based on evidence from ice cores that preserve ancient atmospheric gases (figure $\PageIndex{d-f}$). Human activities currently release over 30 billion tons of CO 2 into the atmosphere every year. While some volcanic eruptions released large quantities of CO 2 in the distant past, the U.S. Geological Survey (USGS) reports that human activities now emit more than 135 times as much CO 2 as volcanoes each year. This human-caused build-up of CO 2 in the atmosphere is like a tub filling with water, where more water flows from the faucet than the drain can take away.

Line graph shows an increase in atmospheric carbon dioxide over time with fluctuations between seasons each year

Other Greenhouse Gasses

Although this concentration is far less than that of CO 2 , methane (CH 4 ) is 28 times as potent a greenhouse gas. Methane is produced when bacteria break down organic matter under anaerobic conditions and can be released due to natural or anthropogenic processes. Anaerobic conditions can happen when organic matter is trapped underwater (such as in rice paddies) or in the intestines of herbivores. Anthropogenic causes now account for 60% of total methane release. Examples include agriculture, fossil fuel extraction and transport, mining, landfill use, and burning of forests. Specifically, raising cattle releases methane due to fermentation in their rumens produces methane that is expelled from their GI tract. Methane is more abundant in Earth’s atmosphere now than at any time in at least the past 650,000 years, and CH 4 concentrations increased sharply during most of the 20th century. They are now more than two and-a-half times pre-industrial levels (1.9 ppm), but the rate of increase has slowed considerably in recent decades.

Water vapor is the most abundant greenhouse gas and also the most important in terms of its contribution to the natural greenhouse effect, despite having a short atmospheric lifetime. Some human activities can influence local water vapor levels. However, on a global scale, the concentration of water vapor is controlled by temperature, which influences overall rates of evaporation and precipitation. Therefore, the global concentration of water vapor is not substantially affected by direct human emissions.

Ground-level ozone (O 3 ), which also has a short atmospheric lifetime, is a potent greenhouse gas. Chemical reactions create ozone from emissions of nitrogen oxides and volatile organic compounds from automobiles, power plants, and other industrial and commercial sources in the presence of sunlight (as discussed in section 10.1). In addition to trapping heat, ozone is a pollutant that can cause respiratory health problems and damage crops and ecosystems.

Changes in the Sun’s Energy Affect how Much Energy Reaches Earth

Climate can be influenced by natural changes that affect how much solar energy reaches Earth. These changes include changes within the sun and changes in Earth’s orbit. Changes occurring in the sun itself can affect the intensity of the sunlight that reaches Earth’s surface. The intensity of the sunlight can cause either warming (during periods of stronger solar intensity) or cooling (during periods of weaker solar intensity). The sun follows a natural 11-year cycle of small ups and downs in intensity, but the effect on Earth’s climate is small. Changes in the shape of Earth’s orbit as well as the tilt and position of Earth’s axis can also affect the amount of sunlight reaching Earth’s surface.

Changes in the sun’s intensity have influenced Earth’s climate in the past. For example, the so-called “ Little Ice Age ” between the 17th and 19th centuries may have been partially caused by a low solar activity phase from 1645 to 1715, which coincided with cooler temperatures. The Little Ice Age refers to a slight cooling of North America, Europe, and probably other areas around the globe. Changes in Earth’s orbit have had a big impact on climate over tens of thousands of years. These changes appear to be the primary cause of past cycles of ice ages, in which Earth has experienced long periods of cold temperatures (ice ages), as well as shorter interglacial periods (periods between ice ages) of relatively warmer temperatures.

Changes in solar energy continue to affect climate. However, solar activity has been relatively constant, aside from the 11-year cycle, since the mid-20th century and therefore does not explain the recent warming of Earth. Similarly, changes in the shape of Earth’s orbit as well as the tilt and position of Earth’s axis affect temperature on relatively long timescales (tens of thousands of years), and therefore cannot explain the recent warming.

Changes in Reflectivity Affect How Much Energy Enters Earth’s System

When sunlight energy reaches Earth it can be reflected or absorbed. The amount that is reflected or absorbed depends on Earth’s surface and atmosphere. Light-colored objects and surfaces, like snow and clouds, tend to reflect most sunlight, while darker objects and surfaces, like the ocean and forests, tend to absorb more sunlight. The term albedo refers to the amount of solar radiation reflected from an object or surface, often expressed as a percentage. Earth as a whole has an albedo of about 30%, meaning that 70% of the sunlight that reaches the planet is absorbed. Sunlight that is absorbed warms Earth’s land, water, and atmosphere.

Albedo is also affected by aerosols. Aerosols are small particles or liquid droplets in the atmosphere that can absorb or reflect sunlight. Unlike greenhouse gases (GHGs), the climate effects of aerosols vary depending on what they are made of and where they are emitted. Those aerosols that reflect sunlight, such as particles from volcanic eruptions or sulfur emissions from burning coal, have a cooling effect. Those that absorb sunlight, such as black carbon (a part of soot), have a warming effect.

Natural changes in albedo, like the melting of sea ice or increases in cloud cover, have contributed to climate change in the past, often acting as feedbacks to other processes. Volcanoes have played a noticeable role in climate. Volcanic particles that reach the upper atmosphere can reflect enough sunlight back to space to cool the surface of the planet by a few tenths of a degree for several years. Volcanic particles from a single eruption do not produce long-term change because they remain in the atmosphere for a much shorter time than GHGs.

Human changes in land use and land cover have changed Earth’s albedo. Processes such as deforestation, reforestation, desertification, and urbanization often contribute to changes in climate in the places they occur. These effects may be significant regionally, but are smaller when averaged over the entire globe.

Scientific Consensus: Global Climate Change is Real

The Intergovernmental Panel on Climate Change (IPCC) was created in 1988 by the United Nations Environment Programme and the World Meteorological Organization. It is charged with the task of evaluating and synthesizing the scientific evidence surrounding global climate change. The IPCC uses this information to evaluate current impacts and future risks, in addition to providing policymakers with assessments. These assessments are released about once every every six years. The most recent report, the 5th Assessment, was released in 2013. Hundreds of leading scientists from around the world are chosen to author these reports. Over the history of the IPCC, these scientists have reviewed thousands of peer-reviewed, publicly available studies. The scientific consensus is clear: global climate change is real and humans are very likely the cause for this change.

Additionally, the major scientific agencies of the United States, including the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA), also agree that climate change is occurring and that humans are driving it. In 2010, the US National Research Council concluded that “Climate change is occurring, is very likely caused by human activities, and poses significant risks for a broad range of human and natural systems”. Many independent scientific organizations have released similar statements, both in the United States and abroad. This doesn’t necessarily mean that every scientist sees eye to eye on each component of the climate change problem, but broad agreement exists that climate change is happening and is primarily caused by excess greenhouse gases from human activities. Critics of climate change, driven by ideology instead of evidence, try to suggest to the public that there is no scientific consensus on global climate change. Such an assertion is patently false.

Current Status of Global Climate Change and Future Changes

Greenhouse gas concentrations in the atmosphere will continue to increase unless the billions of tons of anthropogenic emissions each year decrease substantially. Increased concentrations are expected to do the following:

Increase Earth’s average temperature (figure $\PageIndex{g}$),
Influence the patterns and amounts of precipitation,
Reduce ice and snow cover, as well as permafrost,
Raise sea level (figure $\PageIndex{h}$),
Increase the acidity of the oceans.

Line graph shows overall increases in sea height from 1993 to 2020

Figure $\PageIndex{h}$: Sea height variation (mm) over time. Sea height has increased about 3.3 millimeters per year on average since 1993. Data is from satellite sea level observations by the NASA Goddard Space Flight Center. Image by NASA (public domain).

These changes will impact our food supply, water resources, infrastructure, ecosystems, and even our own health. The magnitude and rate of future climate change will primarily depend on the following factors:

The rate at which levels of greenhouse gas concentrations in our atmosphere continue to increase,
How strongly features of the climate (e.g., temperature, precipitation, and sea level) respond to the expected increase in greenhouse gas concentrations,
Natural influences on climate (e.g., from volcanic activity and changes in the sun’s intensity) and natural processes within the climate system (e.g., changes in ocean circulation patterns).

Past and Present-day GHG Emissions Will Affect Climate Far into the Future

Many greenhouse gases stay in the atmosphere for long periods of time. As a result, even if emissions stopped increasing, atmospheric greenhouse gas concentrations would continue to remain elevated for hundreds of years. Moreover, if we stabilized concentrations and the composition of today’s atmosphere remained steady (which would require a dramatic reduction in current greenhouse gas emissions), surface air temperatures would continue to warm. This is because the oceans, which store heat, take many decades to fully respond to higher greenhouse gas concentrations. The ocean’s response to higher greenhouse gas concentrations and higher temperatures will continue to impact climate over the next several decades to hundreds of years.

Future Temperature Changes

Climate models project the following key temperature-related changes:

Average global temperatures are expected to increase by 2°F to 11.5°F by 2100, depending on the level of future greenhouse gas emissions, and the outcomes from various climate models.
By 2100, global average temperature is expected to warm at least twice as much as it has during the last 100 years.
Ground-level air temperatures are expected to continue to warm more rapidly over land than oceans.
Some parts of the world are projected to see larger temperature increases than the global average.

Future Precipitation and Storm Events

Patterns of precipitation and storm events, including both rain and snowfall are likely to change. However, some of these changes are less certain than the changes associated with temperature. Projections show that future precipitation and storm changes will vary by season and region. Some regions may have less precipitation, some may have more precipitation, and some may have little or no change. The amount of rain falling in heavy precipitation events is likely to increase in most regions, while storm tracks are projected to shift towards the poles. Climate models project the following precipitation and storm changes:

Global average annual precipitation through the end of the century is expected to increase, although changes in the amount and intensity of precipitation will vary by region.
The intensity of precipitation events will likely increase on average. This will be particularly pronounced in tropical and high-latitude regions, which are also expected to experience overall increases in precipitation.
The strength of the winds associated with tropical storms is likely to increase. The amount of precipitation falling in tropical storms is also likely to increase.
Annual average precipitation is projected to increase in some areas and decrease in others.

Future Ice, Snowpack, and Permafrost

Arctic sea ice is already declining drastically. The area of snow cover in the Northern Hemisphere has decreased since 1970. Permafrost temperature has increased over the last century, making it more susceptible to thawing. Over the next century, it is expected that sea ice will continue to decline, glaciers will continue to shrink, snow cover will continue to decrease, and permafrost will continue to thaw.

For every 2°F of warming, models project about a 15% decrease in the extent of annually averaged sea ice and a 25% decrease in September Arctic sea ice. The coastal sections of the Greenland and Antarctic ice sheets are expected to continue to melt or slide into the ocean. If the rate of this ice melting increases in the 21st century, the ice sheets could add significantly to global sea level rise. Glaciers are expected to continue to decrease in size. The rate of melting is expected to continue to increase, which will contribute to sea level rise.

Future Sea Level Change

Warming temperatures contribute to sea level rise by expanding ocean water, melting mountain glaciers and ice caps, and causing portions of the Greenland and Antarctic ice sheets to melt or flow into the ocean. Since 1870, global sea level has risen by about 8 inches. Estimates of future sea level rise vary for different regions, but global sea level for the next century is expected to rise at a greater rate than during the past 50 years. The contribution of thermal expansion, ice caps, and small glaciers to sea level rise is relatively well-studied, but the impacts of climate change on ice sheets are less understood and represent an active area of research. Thus, it is more difficult to predict how much changes in ice sheets will contribute to sea level rise. Greenland and Antarctic ice sheets could contribute an additional 1 foot of sea level rise, depending on how the ice sheets respond.

Regional and local factors will influence future relative sea level rise for specific coastlines around the world (figure $\PageIndex{i}$). For example, relative sea level rise depends on land elevation changes that occur as a result of subsidence (sinking) or uplift (rising), in addition to things such as local currents, winds, salinity, water temperatures, and proximity to thinning ice sheets. Assuming that these historical geological forces continue, a 2-foot rise in global sea level by 2100 would result in the following relative sea level rise:

2.3 feet at New York City
2.9 feet at Hampton Roads, Virginia
3.5 feet at Galveston, Texas
1 foot at Neah Bay in Washington state

The yard of a damaged house is flooded, and a tree stump is submerged

Future Ocean Acidification

Ocean acidification is the process of ocean waters decreasing in pH. Oceans become more acidic as carbon dioxide (CO 2 ) emissions in the atmosphere dissolve in the ocean. This change is measured on the pH scale, with lower values being more acidic. The pH level of the oceans has decreased by approximately 0.1 pH units since pre-industrial times, which is equivalent to a 25% increase in acidity. The pH level of the oceans is projected to decrease even more by the end of the century as CO 2 concentrations are expected to increase for the foreseeable future. Ocean acidification adversely affects many marine species, including plankton, mollusks, shellfish, and corals. As ocean acidification increases, the availability of calcium carbonate will decline. Calcium carbonate is a key building block for the shells and skeletons of many marine organisms. If atmospheric CO 2 concentrations double, coral calcification rates are projected to decline by more than 30%. If CO 2 concentrations continue to rise at their current rate, corals could become rare on tropical and subtropical reefs by 2050.

Mismatched Interactions

Climate change also affects phenology, the study of the effects of climatic conditions on the timing of periodic lifecycle events, such as flowering in plants or migration in birds. Researchers have shown that 385 plant species in Great Britain are flowering 4.5 days sooner than was recorded earlier during the previous 40 years. In addition, insect-pollinated species were more likely to flower earlier than wind-pollinated species. The impact of changes in flowering date would be mitigated if the insect pollinators emerged earlier. This mismatched timing of plants and pollinators could result in injurious ecosystem effects because, for continued survival, insect-pollinated plants must flower when their pollinators are present.

Likewise, migratory birds rely on daylength cues, which are not influenced by climate change. Their insect food sources, however, emerge earlier in the year in response to warmer temperatures. As a result, climate change decreases food availability for migratory bird species.

Spread of Disease

This rise in global temperatures will increase the range of disease-carrying insects and the viruses and pathogenic parasites they harbor. Thus, diseases will spread to new regions of the globe. This spread has already been documented with dengue fever, a disease the affects hundreds of millions per year, according to the World Health Organization. Colder temperatures typically limit the distribution of certain species, such as the mosquitoes that transmit malaria, because freezing temperatures destroy their eggs.

Not only will the range of some disease-causing insects expand, the increasing temperatures will also accelerate their lifecycles, which allows them to breed and multiply quicker, and perhaps evolve pesticide resistance faster. In addition to dengue fever, other diseases are expected to spread to new portions of the world as the global climate warms. These include malaria, yellow fever, West Nile virus, zika virus, and chikungunya.

Climate change does not only increase the spread of diseases in humans. Rising temperatures are associated with greater amphibian mortality due to chytridiomycosis (see Invasive Species ). Similarly, warmer temperatures have exacerbated bark beetle infestations of coniferous trees, such as pine an spruce.

Climate Change Affects Everyone

Our lives are connected to the climate . Human societies have adapted to the relatively stable climate we have enjoyed since the last ice age which ended several thousand years ago. A warming climate will bring changes that can affect our water supplies, agriculture, power and transportation systems, the natural environment, and even our own health and safety.

Carbon dioxide can stay in the atmosphere for nearly a century, on average, so Earth will continue to warm in the coming decades. The warmer it gets, the greater the risk for more severe changes to the climate and Earth’s system. Although it’s difficult to predict the exact impacts of climate change, what’s clear is that the climate we are accustomed to is no longer a reliable guide for what to expect in the future.

We can reduce the risks we will face from climate change . By making choices that reduce greenhouse gas pollution, and preparing for the changes that are already underway, we can reduce risks from climate change. Our decisions today will shape the world our children and grandchildren will live in.

You can take steps at home, on the road, and in your office to reduce greenhouse gas emissions and the risks associated with climate change. Many of these steps can save you money. Some, such as walking or biking to work, can even improve your health! You can also get involved on a local or state level to support energy efficiency, clean energy programs, or other climate programs.

Attributions

Modified by Melissa Ha from the following sources:

Climate and the Effects of Global Climate Change from General Biology by OpenStax (licensed under CC-BY )
Climate Change from Environmental Biology by Matthew R. Fisher (licensed under CC-BY )
Carbon Cycle from Biology by John W. Kimball (licensed under CC-BY )

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Greenhouse Effect

By thomas schelling.

By Thomas Schelling,

What Is It?

The “greenhouse effect” is a complicated process by which the earth is becoming progressively warmer. The earth is bathed in sunlight, some of it reflected back into space and some absorbed. If the absorption is not matched by radiation back into space, the earth will get warmer until the intensity of that radiation matches the incoming sunlight. Some atmospheric gases absorb outward infrared radiation, warming the atmosphere. Carbon dioxide is one of these gases; so are methane, nitrous oxide, and the chlorofluorocarbons (CFCs). The concentrations of these gases are increasing, with the result that the earth is absorbing more sunlight and getting warmer.

This greenhouse phenomenon is truly the result of a “global common” (see The Tragedy of the Commons ). Because no one owns the atmosphere, no one has a sufficient incentive to take account of the change to the atmosphere caused by his or her emission of carbon. Also, carbon emitted has the same effect no matter where on earth it happens.

How Serious Is It?

The expected change in global average temperature for a doubling of CO 2 is 1.5 to 4.5 degrees centigrade. But translating a change in temperature into a change in climates is full of uncertainties. Meteorologists predict greater temperature change in the polar regions than near the equator. This change could cause changes in circulation of air and water. The results may be warmer temperatures in some places and colder in others, wetter climates in some places and drier in others.

Temperature is useful as an index of climate change. A band of about one degree covers variations in average temperatures since the last ice age. This means that climates will change more in the next one hundred years than in the last ten thousand. But to put this in perspective, remember that people have been migrating great distances for thousands of years, experiencing changes in climate greater than any being forecast.

The models of global warming project only gradual changes. Climates will “migrate” slowly. The climate of Kansas may become like Oklahoma’s, but not like that of Oregon or Massachusetts. But a caveat is in order: the models probably cannot project discontinuities because nothing goes into them that will produce drastic change. There may be phenomena that could produce drastic changes, but they are not known with enough confidence to introduce into the models.

Carbon dioxide has increased about 25 percent since the onset of the industrial revolution. The global average temperature rose almost half a degree during the first forty years of this century, was level for the next forty, and rose during the eighties. Yet whether or not we are witnessing the greenhouse effect is unknown because other decades-long influences such as changes in solar intensity and in the atmosphere’s particulate matter can obscure any smooth greenhouse trend. In other words, the increase in carbon dioxide will, by itself, cause the greenhouse effect, but other changes in the universe may offset it.

Even if we had confident estimates of climate change for different regions of the world, there would be uncertainties about the kind of world we will have fifty or a hundred years from now. Suppose the kind of climate change expected between now and, say, 2080 had already taken place, since 1900. Ask a seventy-five-year-old farm couple living on the same farm where they were born: would the change in the climate be among the most dramatic changes in either their farming or their lifestyle? The answer most likely would be no. Changes from horses to tractors and from kerosene to electricity would be much more important.

Climate change would have made a vastly greater difference to the way people lived and earned their living in 1900 than today. Today, little of our gross domestic product is produced outdoors, and therefore, little is susceptible to climate. Agriculture and forestry are less than 3 percent of total output, and little else is much affected. Even if agricultural productivity declined by a third over the next half-century, the per capita GNP we might have achieved by 2050 we would still achieve in 2051. Considering that agricultural productivity in most parts of the world continues to improve (and that many crops may benefit directly from enhanced photosynthesis due to increased carbon dioxide), it is not at all certain that the net impact on agriculture will be negative or much noticed in the developed world.

Its Effects on Developing Countries

Climate changes would have greater impact in underdeveloped countries. Agriculture provides the livelihoods of 30 percent or more of the population in much of the developing world. While there is no strong presumption that the climates prevailing in different regions fifty or a hundred years from now will be less conducive to food production, those people are vulnerable in a way that Americans and west Europeans are not. Nor can the impact on their health be dismissed. Parasitic and other vectorborne diseases affecting hundreds of millions of people are sensitive to climate.

Yet the trend in developing countries is to be less dependent on agriculture. If per capita income in such countries grows in the next forty years as rapidly as it has in the forty just past, vulnerability to climate change should diminish. This is pertinent to whether developing countries should make sacrifices to minimize the emission of gases that may change climate to their disadvantage. Their best defense against climate change will be their own continued development.

Population is an important factor. Carbon emissions in developing countries rise with population. For instance, if China holds population growth to near zero for the next couple of generations, it may do as much for the earth’s atmosphere as would a heroic anticarbon program coupled with 2 percent annual population growth. Furthermore, the most likely adverse impact of climate change would be on food production, and in the poorest parts of the world the adequacy of food depends on the number of mouths.

Why Should Developed Countries Do Anything?

Why might developed countries care enough about climate to do anything about it? The answer depends on how much people in developed countries care about people in developing countries and on how expensive it is to do something worthwhile. Abatement programs in a number of econometric models suggest that doing something worthwhile would cost about 2 percent of GNP in perpetuity. Two percent of the U.S. GNP is over $100 billion a year, and that is an annual cost that would continue forever.

One argument for doing something is that the developing countries are vulnerable, and we care about their well-being. But if the developed countries were prepared to invest, say, $200 billion a year in greenhouse gas abatement, explicitly for the benefit of developing countries fifty years or more from now, the developing countries would probably clamor, understandably, to receive the resources immediately in support of their continued development.

A second argument is that our natural environment may be severely damaged. This is the crux of the political debate over the greenhouse effect, but it is an issue that no one really understands. It is difficult to know how to value what is at risk, and difficult even to know just what is at risk. The benefits of slowing climate change by some particular amount are even more uncertain.

A third argument is that the conclusion I reported earlier—that climates will change slowly and not much—may be wrong. The models do not produce surprises. The possibility has to be considered that some atmospheric or oceanic circulatory systems may flip to alternative equilibria, producing regional changes that are sudden and extreme. A currently discussed possibility is in the way oceans behave. If the gulf stream flipped into a new pattern, the climatic consequences might be sudden and severe. (Paradoxically, global warming might severely cool western Europe.)

Is 2 percent of GNP forever, to postpone the doubling of carbon in the atmosphere, a big number or a small one? That depends on what the comparison is. A better question—assuming we were prepared to spend 2 percent of GNP to reduce the damage from climate change—is whether we might find better uses for the money.

I mentioned one such use—directly investing to improve the economies of the poorer countries. Another would be direct investment in preserving species or ecosystems or wilderness areas, if the alternative is to invest trillions in the reduction of carbon emissions.

What Solutions Are Proposed?

What can be done to reduce or offset carbon emissions? Reducing energy use and the carbon content of energy have received most of the attention. There are other possibilities. Trees store carbon. A new forest will absorb carbon until it reaches maturity; it then holds its carbon but does not absorb more. The area available for reforestation throughout the world suggests that reforestation can contribute, but not much.

Stopping or slowing deforestation is important for other reasons but is quantitatively more important than reforestation, partly because forest subsoils typically contain carbon greater than the amount in the trees themselves, and this carbon is subject to oxidation when the trees are removed.

Also, substances or objects can be put in orbit or in the stratosphere to reflect incoming sunlight. Some of these are as apparently innocuous as stimulating cloud formation and some as dramatic as huge mylar balloons in low earth orbit. If in decades to come the greenhouse impact confirms the more alarmist expectations, and if the costs of reducing emissions prove unmanageable, some of these “geoengineering” options will invite attention.

The main responses will be to adapt as the climate changes and to reduce carbon emissions. (CFCs are potent greenhouse gases and, if unchecked, might have rivaled carbon dioxide in decades to come. International actions to reduce or eliminate CFCs are making progress and are among the cheapest ways of reducing greenhouse emissions.)

It is improbable that the developing world, at least for the next several decades, will incur any significant sacrifice in the interest of reduced carbon, nor would it be advisable. Financing energy conservation, energy efficiency, and a switch from high-carbon to lower-carbon or noncarbon fuels in Asia and Africa would not only be a major economic enterprise, but also a complex effort in international diplomacy and politics. If successful, it would increase the costs to the developed world by at least another percent or two on top of the 2 percent I mentioned.

A universal carbon tax is a popular proposal among economists because it promises an efficient solution. A carbon tax set equally for all users worldwide would achieve a given reduction in the use of carbon at the lowest cost. If user A values his use of one ton of carbon at two thousand dollars more than its net-of-tax price, and if the tax is four hundred dollars per ton, he will continue to use the carbon because doing so is worthwhile. If user B values his use of one ton at only three hundred dollars more than the net-of-tax price, the tax will induce him to end his use. Thus the tax would eliminate the lowest-valued uses of carbon and would leave the highest-valued ones in place. A carbon tax would require no negotiation except over a tax rate and a formula for distributing the proceeds. But a tax rate that made a big dent in the greenhouse problem would have to be equivalent to around a dollar per gallon on motor fuel, and for the United States alone such a tax on coal, petroleum, and natural gas would currently yield close to half a trillion dollars per year in revenue, almost 10 percent of our GNP. It is doubtful that any greenhouse taxing agency would be allowed to collect that kind of revenue, or that a treaty requiring the United States to levy internal carbon taxation at that level would be ratified.

Tradable permits have been proposed as an alternative to the tax. The main possibilities are estimating “reasonable” emissions country by country and establishing commensurate quotas, or distributing tradable rights in accordance with some “equitable” criterion. Depending on how restrictive the emission rights might be, the latter amounts to distributing trillions of dollars (in present value terms), an unlikely prospect. If quotas are negotiated to correspond to countries’ currently “reasonable” emissions levels, they will surely be renegotiated every few years, and selling an emissions right will be perceived as evidence that a quota was initially too generous.

A helpful model for conceptualizing a greenhouse regime among the richer countries is the negotiations among the nations of Western Europe for distributing Marshall Plan aid after World War II. There was never a formula or explicit criterion, such as equalizing living standards, maximizing aggregate growth, or establishing a floor under levels of living. Baseline dollar-balance-of-payments deficits were a point of departure, but the negotiations took into account other factors such as investment needs and traditional consumption levels. The United States insisted that the recipients argue out and agree on shares. In the end they did not quite make it, the United States having to make the final allocation. But all the submission of data and open argument led, if not to consensus, to a reasonable appreciation of each nation’s needs. Distribution of Marshall Plan funds is the only model of multilateral negotiation involving resources commensurate with the cost of greenhouse abatement. (In the first year Marshall Plan funds were about 1.5 percent of U.S. GNP and—adjusting for overvalued currencies—probably 5 percent of recipient countries’ GNP.)

What the Marshall Plan model suggests is that the participants in a greenhouse regime would submit for each other’s scrutiny and cross-examination plans for reducing carbon emissions. The plans would be accompanied by estimates of emissions, but any commitments would be to the policies, not the emissions.

The alternative is commitments to specific levels of emissions. Because target dates would be a decade or two in the future, monitoring a country’s progress would be more ambiguous than monitoring the implementation of policies.

______________________________________________________________________________________________________________________________

Thomas C. Schelling is a professor of economics at the University of Maryland School of Public Affairs in College Park. For most of his professional life he was an economics professor at Harvard University. In 1991 he was president of the American Economic Association. He is an elected member of the National Academy of Sciences.

Ausubel, Jesse. “Does Climate Still Matter?” Nature 350, April 25, 1991, 649-52.

Cline, William R. The Greenhouse Effect: Global Economic Consequences. 1992.

Congressional Budget Office. Carbon Charges as a Response to Global Warming: The Effects of Taxing Fossil Fuels. 1990.

Dornbush, Rudiger, and James M. Poterba. Global Warming: Economic Policy Responses. 1991.

Nordhaus, William D. “The Cost of Slowing Climate Change: A Survey.” Energy Journal 12, no. 1 (1991): 37-66.

_______________________________________________________________________________________________________________________________

The Science of Climate Change Explained: Facts, Evidence and Proof

Definitive answers to the big questions.

Credit... Photo Illustration by Andrea D'Aquino

Supported by

By Julia Rosen

Ms. Rosen is a journalist with a Ph.D. in geology. Her research involved studying ice cores from Greenland and Antarctica to understand past climate changes.

Published April 19, 2021 Updated Nov. 6, 2021

The science of climate change is more solid and widely agreed upon than you might think. But the scope of the topic, as well as rampant disinformation, can make it hard to separate fact from fiction. Here, we’ve done our best to present you with not only the most accurate scientific information, but also an explanation of how we know it.

How do we know climate change is really happening?

How much agreement is there among scientists about climate change, do we really only have 150 years of climate data how is that enough to tell us about centuries of change, how do we know climate change is caused by humans, since greenhouse gases occur naturally, how do we know they’re causing earth’s temperature to rise, why should we be worried that the planet has warmed 2°f since the 1800s, is climate change a part of the planet’s natural warming and cooling cycles, how do we know global warming is not because of the sun or volcanoes, how can winters and certain places be getting colder if the planet is warming, wildfires and bad weather have always happened. how do we know there’s a connection to climate change, how bad are the effects of climate change going to be, what will it cost to do something about climate change, versus doing nothing.

Climate change is often cast as a prediction made by complicated computer models. But the scientific basis for climate change is much broader, and models are actually only one part of it (and, for what it’s worth, they’re surprisingly accurate ).

For more than a century , scientists have understood the basic physics behind why greenhouse gases like carbon dioxide cause warming. These gases make up just a small fraction of the atmosphere but exert outsized control on Earth’s climate by trapping some of the planet’s heat before it escapes into space. This greenhouse effect is important: It’s why a planet so far from the sun has liquid water and life!

However, during the Industrial Revolution, people started burning coal and other fossil fuels to power factories, smelters and steam engines, which added more greenhouse gases to the atmosphere. Ever since, human activities have been heating the planet.

We know this is true thanks to an overwhelming body of evidence that begins with temperature measurements taken at weather stations and on ships starting in the mid-1800s. Later, scientists began tracking surface temperatures with satellites and looking for clues about climate change in geologic records. Together, these data all tell the same story: Earth is getting hotter.

Average global temperatures have increased by 2.2 degrees Fahrenheit, or 1.2 degrees Celsius, since 1880, with the greatest changes happening in the late 20th century. Land areas have warmed more than the sea surface and the Arctic has warmed the most — by more than 4 degrees Fahrenheit just since the 1960s. Temperature extremes have also shifted. In the United States, daily record highs now outnumber record lows two-to-one.

Where it was cooler or warmer in 2020 compared with the middle of the 20th century

This warming is unprecedented in recent geologic history. A famous illustration, first published in 1998 and often called the hockey-stick graph, shows how temperatures remained fairly flat for centuries (the shaft of the stick) before turning sharply upward (the blade). It’s based on data from tree rings, ice cores and other natural indicators. And the basic picture , which has withstood decades of scrutiny from climate scientists and contrarians alike, shows that Earth is hotter today than it’s been in at least 1,000 years, and probably much longer.

In fact, surface temperatures actually mask the true scale of climate change, because the ocean has absorbed 90 percent of the heat trapped by greenhouse gases . Measurements collected over the last six decades by oceanographic expeditions and networks of floating instruments show that every layer of the ocean is warming up. According to one study , the ocean has absorbed as much heat between 1997 and 2015 as it did in the previous 130 years.

We also know that climate change is happening because we see the effects everywhere. Ice sheets and glaciers are shrinking while sea levels are rising. Arctic sea ice is disappearing. In the spring, snow melts sooner and plants flower earlier. Animals are moving to higher elevations and latitudes to find cooler conditions. And droughts, floods and wildfires have all gotten more extreme. Models predicted many of these changes, but observations show they are now coming to pass.

There’s no denying that scientists love a good, old-fashioned argument. But when it comes to climate change, there is virtually no debate: Numerous studies have found that more than 90 percent of scientists who study Earth’s climate agree that the planet is warming and that humans are the primary cause. Most major scientific bodies, from NASA to the World Meteorological Organization , endorse this view. That’s an astounding level of consensus given the contrarian, competitive nature of the scientific enterprise, where questions like what killed the dinosaurs remain bitterly contested .

Scientific agreement about climate change started to emerge in the late 1980s, when the influence of human-caused warming began to rise above natural climate variability. By 1991, two-thirds of earth and atmospheric scientists surveyed for an early consensus study said that they accepted the idea of anthropogenic global warming. And by 1995, the Intergovernmental Panel on Climate Change, a famously conservative body that periodically takes stock of the state of scientific knowledge, concluded that “the balance of evidence suggests that there is a discernible human influence on global climate.” Currently, more than 97 percent of publishing climate scientists agree on the existence and cause of climate change (as does nearly 60 percent of the general population of the United States).

So where did we get the idea that there’s still debate about climate change? A lot of it came from coordinated messaging campaigns by companies and politicians that opposed climate action. Many pushed the narrative that scientists still hadn’t made up their minds about climate change, even though that was misleading. Frank Luntz, a Republican consultant, explained the rationale in an infamous 2002 memo to conservative lawmakers: “Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly,” he wrote. Questioning consensus remains a common talking point today, and the 97 percent figure has become something of a lightning rod .

To bolster the falsehood of lingering scientific doubt, some people have pointed to things like the Global Warming Petition Project, which urged the United States government to reject the Kyoto Protocol of 1997, an early international climate agreement. The petition proclaimed that climate change wasn’t happening, and even if it were, it wouldn’t be bad for humanity. Since 1998, more than 30,000 people with science degrees have signed it. However, nearly 90 percent of them studied something other than Earth, atmospheric or environmental science, and the signatories included just 39 climatologists. Most were engineers, doctors, and others whose training had little to do with the physics of the climate system.

A few well-known researchers remain opposed to the scientific consensus. Some, like Willie Soon, a researcher affiliated with the Harvard-Smithsonian Center for Astrophysics, have ties to the fossil fuel industry . Others do not, but their assertions have not held up under the weight of evidence. At least one prominent skeptic, the physicist Richard Muller, changed his mind after reassessing historical temperature data as part of the Berkeley Earth project. His team’s findings essentially confirmed the results he had set out to investigate, and he came away firmly convinced that human activities were warming the planet. “Call me a converted skeptic,” he wrote in an Op-Ed for the Times in 2012.

Mr. Luntz, the Republican pollster, has also reversed his position on climate change and now advises politicians on how to motivate climate action.

A final note on uncertainty: Denialists often use it as evidence that climate science isn’t settled. However, in science, uncertainty doesn’t imply a lack of knowledge. Rather, it’s a measure of how well something is known. In the case of climate change, scientists have found a range of possible future changes in temperature, precipitation and other important variables — which will depend largely on how quickly we reduce emissions. But uncertainty does not undermine their confidence that climate change is real and that people are causing it.

Earth’s climate is inherently variable. Some years are hot and others are cold, some decades bring more hurricanes than others, some ancient droughts spanned the better part of centuries. Glacial cycles operate over many millenniums. So how can scientists look at data collected over a relatively short period of time and conclude that humans are warming the planet? The answer is that the instrumental temperature data that we have tells us a lot, but it’s not all we have to go on.

Historical records stretch back to the 1880s (and often before), when people began to regularly measure temperatures at weather stations and on ships as they traversed the world’s oceans. These data show a clear warming trend during the 20th century.

Global average temperature compared with the middle of the 20th century

+0.75°C

–0.25°

Some have questioned whether these records could be skewed, for instance, by the fact that a disproportionate number of weather stations are near cities, which tend to be hotter than surrounding areas as a result of the so-called urban heat island effect. However, researchers regularly correct for these potential biases when reconstructing global temperatures. In addition, warming is corroborated by independent data like satellite observations, which cover the whole planet, and other ways of measuring temperature changes.

Much has also been made of the small dips and pauses that punctuate the rising temperature trend of the last 150 years. But these are just the result of natural climate variability or other human activities that temporarily counteract greenhouse warming. For instance, in the mid-1900s, internal climate dynamics and light-blocking pollution from coal-fired power plants halted global warming for a few decades. (Eventually, rising greenhouse gases and pollution-control laws caused the planet to start heating up again.) Likewise, the so-called warming hiatus of the 2000s was partly a result of natural climate variability that allowed more heat to enter the ocean rather than warm the atmosphere. The years since have been the hottest on record .

Still, could the entire 20th century just be one big natural climate wiggle? To address that question, we can look at other kinds of data that give a longer perspective. Researchers have used geologic records like tree rings, ice cores, corals and sediments that preserve information about prehistoric climates to extend the climate record. The resulting picture of global temperature change is basically flat for centuries, then turns sharply upward over the last 150 years. It has been a target of climate denialists for decades. However, study after study has confirmed the results , which show that the planet hasn’t been this hot in at least 1,000 years, and probably longer.

Scientists have studied past climate changes to understand the factors that can cause the planet to warm or cool. The big ones are changes in solar energy, ocean circulation, volcanic activity and the amount of greenhouse gases in the atmosphere. And they have each played a role at times.

For example, 300 years ago, a combination of reduced solar output and increased volcanic activity cooled parts of the planet enough that Londoners regularly ice skated on the Thames . About 12,000 years ago, major changes in Atlantic circulation plunged the Northern Hemisphere into a frigid state. And 56 million years ago, a giant burst of greenhouse gases, from volcanic activity or vast deposits of methane (or both), abruptly warmed the planet by at least 9 degrees Fahrenheit, scrambling the climate, choking the oceans and triggering mass extinctions.

In trying to determine the cause of current climate changes, scientists have looked at all of these factors . The first three have varied a bit over the last few centuries and they have quite likely had modest effects on climate , particularly before 1950. But they cannot account for the planet’s rapidly rising temperature, especially in the second half of the 20th century, when solar output actually declined and volcanic eruptions exerted a cooling effect.

That warming is best explained by rising greenhouse gas concentrations . Greenhouse gases have a powerful effect on climate (see the next question for why). And since the Industrial Revolution, humans have been adding more of them to the atmosphere, primarily by extracting and burning fossil fuels like coal, oil and gas, which releases carbon dioxide.

Bubbles of ancient air trapped in ice show that, before about 1750, the concentration of carbon dioxide in the atmosphere was roughly 280 parts per million. It began to rise slowly and crossed the 300 p.p.m. threshold around 1900. CO2 levels then accelerated as cars and electricity became big parts of modern life, recently topping 420 p.p.m . The concentration of methane, the second most important greenhouse gas, has more than doubled. We’re now emitting carbon much faster than it was released 56 million years ago .

30 billion metric tons

Carbon dioxide emitted worldwide 1850-2017

Rest of world

Other developed

European Union

Developed economies

Other countries

United States

E.U. and U.K.

These rapid increases in greenhouse gases have caused the climate to warm abruptly. In fact, climate models suggest that greenhouse warming can explain virtually all of the temperature change since 1950. According to the most recent report by the Intergovernmental Panel on Climate Change, which assesses published scientific literature, natural drivers and internal climate variability can only explain a small fraction of late-20th century warming.

Another study put it this way: The odds of current warming occurring without anthropogenic greenhouse gas emissions are less than 1 in 100,000 .

But greenhouse gases aren’t the only climate-altering compounds people put into the air. Burning fossil fuels also produces particulate pollution that reflects sunlight and cools the planet. Scientists estimate that this pollution has masked up to half of the greenhouse warming we would have otherwise experienced.

Greenhouse gases like water vapor and carbon dioxide serve an important role in the climate. Without them, Earth would be far too cold to maintain liquid water and humans would not exist!

Here’s how it works: the planet’s temperature is basically a function of the energy the Earth absorbs from the sun (which heats it up) and the energy Earth emits to space as infrared radiation (which cools it down). Because of their molecular structure, greenhouse gases temporarily absorb some of that outgoing infrared radiation and then re-emit it in all directions, sending some of that energy back toward the surface and heating the planet . Scientists have understood this process since the 1850s .

Greenhouse gas concentrations have varied naturally in the past. Over millions of years, atmospheric CO2 levels have changed depending on how much of the gas volcanoes belched into the air and how much got removed through geologic processes. On time scales of hundreds to thousands of years, concentrations have changed as carbon has cycled between the ocean, soil and air.

Today, however, we are the ones causing CO2 levels to increase at an unprecedented pace by taking ancient carbon from geologic deposits of fossil fuels and putting it into the atmosphere when we burn them. Since 1750, carbon dioxide concentrations have increased by almost 50 percent. Methane and nitrous oxide, other important anthropogenic greenhouse gases that are released mainly by agricultural activities, have also spiked over the last 250 years.

We know based on the physics described above that this should cause the climate to warm. We also see certain telltale “fingerprints” of greenhouse warming. For example, nights are warming even faster than days because greenhouse gases don’t go away when the sun sets. And upper layers of the atmosphere have actually cooled, because more energy is being trapped by greenhouse gases in the lower atmosphere.

We also know that we are the cause of rising greenhouse gas concentrations — and not just because we can measure the CO2 coming out of tailpipes and smokestacks. We can see it in the chemical signature of the carbon in CO2.

Carbon comes in three different masses: 12, 13 and 14. Things made of organic matter (including fossil fuels) tend to have relatively less carbon-13. Volcanoes tend to produce CO2 with relatively more carbon-13. And over the last century, the carbon in atmospheric CO2 has gotten lighter, pointing to an organic source.

We can tell it’s old organic matter by looking for carbon-14, which is radioactive and decays over time. Fossil fuels are too ancient to have any carbon-14 left in them, so if they were behind rising CO2 levels, you would expect the amount of carbon-14 in the atmosphere to drop, which is exactly what the data show .

It’s important to note that water vapor is the most abundant greenhouse gas in the atmosphere. However, it does not cause warming; instead it responds to it . That’s because warmer air holds more moisture, which creates a snowball effect in which human-caused warming allows the atmosphere to hold more water vapor and further amplifies climate change. This so-called feedback cycle has doubled the warming caused by anthropogenic greenhouse gas emissions.

A common source of confusion when it comes to climate change is the difference between weather and climate. Weather is the constantly changing set of meteorological conditions that we experience when we step outside, whereas climate is the long-term average of those conditions, usually calculated over a 30-year period. Or, as some say: Weather is your mood and climate is your personality.

So while 2 degrees Fahrenheit doesn’t represent a big change in the weather, it’s a huge change in climate. As we’ve already seen, it’s enough to melt ice and raise sea levels, to shift rainfall patterns around the world and to reorganize ecosystems, sending animals scurrying toward cooler habitats and killing trees by the millions.

It’s also important to remember that two degrees represents the global average, and many parts of the world have already warmed by more than that. For example, land areas have warmed about twice as much as the sea surface. And the Arctic has warmed by about 5 degrees. That’s because the loss of snow and ice at high latitudes allows the ground to absorb more energy, causing additional heating on top of greenhouse warming.

Relatively small long-term changes in climate averages also shift extremes in significant ways. For instance, heat waves have always happened, but they have shattered records in recent years. In June of 2020, a town in Siberia registered temperatures of 100 degrees . And in Australia, meteorologists have added a new color to their weather maps to show areas where temperatures exceed 125 degrees. Rising sea levels have also increased the risk of flooding because of storm surges and high tides. These are the foreshocks of climate change.

And we are in for more changes in the future — up to 9 degrees Fahrenheit of average global warming by the end of the century, in the worst-case scenario . For reference, the difference in global average temperatures between now and the peak of the last ice age, when ice sheets covered large parts of North America and Europe, is about 11 degrees Fahrenheit.

Under the Paris Climate Agreement, which President Biden recently rejoined, countries have agreed to try to limit total warming to between 1.5 and 2 degrees Celsius, or 2.7 and 3.6 degrees Fahrenheit, since preindustrial times. And even this narrow range has huge implications . According to scientific studies, the difference between 2.7 and 3.6 degrees Fahrenheit will very likely mean the difference between coral reefs hanging on or going extinct, and between summer sea ice persisting in the Arctic or disappearing completely. It will also determine how many millions of people suffer from water scarcity and crop failures, and how many are driven from their homes by rising seas. In other words, one degree Fahrenheit makes a world of difference.

Earth’s climate has always changed. Hundreds of millions of years ago, the entire planet froze . Fifty million years ago, alligators lived in what we now call the Arctic . And for the last 2.6 million years, the planet has cycled between ice ages when the planet was up to 11 degrees cooler and ice sheets covered much of North America and Europe, and milder interglacial periods like the one we’re in now.

Climate denialists often point to these natural climate changes as a way to cast doubt on the idea that humans are causing climate to change today. However, that argument rests on a logical fallacy. It’s like “seeing a murdered body and concluding that people have died of natural causes in the past, so the murder victim must also have died of natural causes,” a team of social scientists wrote in The Debunking Handbook , which explains the misinformation strategies behind many climate myths.

Indeed, we know that different mechanisms caused the climate to change in the past. Glacial cycles, for example, were triggered by periodic variations in Earth’s orbit , which take place over tens of thousands of years and change how solar energy gets distributed around the globe and across the seasons.

These orbital variations don’t affect the planet’s temperature much on their own. But they set off a cascade of other changes in the climate system; for instance, growing or melting vast Northern Hemisphere ice sheets and altering ocean circulation. These changes, in turn, affect climate by altering the amount of snow and ice, which reflect sunlight, and by changing greenhouse gas concentrations. This is actually part of how we know that greenhouse gases have the ability to significantly affect Earth’s temperature.

For at least the last 800,000 years , atmospheric CO2 concentrations oscillated between about 180 parts per million during ice ages and about 280 p.p.m. during warmer periods, as carbon moved between oceans, forests, soils and the atmosphere. These changes occurred in lock step with global temperatures, and are a major reason the entire planet warmed and cooled during glacial cycles, not just the frozen poles.

Today, however, CO2 levels have soared to 420 p.p.m. — the highest they’ve been in at least three million years . The concentration of CO2 is also increasing about 100 times faster than it did at the end of the last ice age. This suggests something else is going on, and we know what it is: Since the Industrial Revolution, humans have been burning fossil fuels and releasing greenhouse gases that are heating the planet now (see Question 5 for more details on how we know this, and Questions 4 and 8 for how we know that other natural forces aren’t to blame).

Over the next century or two, societies and ecosystems will experience the consequences of this climate change. But our emissions will have even more lasting geologic impacts: According to some studies, greenhouse gas levels may have already warmed the planet enough to delay the onset of the next glacial cycle for at least an additional 50,000 years.

The sun is the ultimate source of energy in Earth’s climate system, so it’s a natural candidate for causing climate change. And solar activity has certainly changed over time. We know from satellite measurements and other astronomical observations that the sun’s output changes on 11-year cycles. Geologic records and sunspot numbers, which astronomers have tracked for centuries, also show long-term variations in the sun’s activity, including some exceptionally quiet periods in the late 1600s and early 1800s.

We know that, from 1900 until the 1950s, solar irradiance increased. And studies suggest that this had a modest effect on early 20th century climate, explaining up to 10 percent of the warming that’s occurred since the late 1800s. However, in the second half of the century, when the most warming occurred, solar activity actually declined . This disparity is one of the main reasons we know that the sun is not the driving force behind climate change.

Another reason we know that solar activity hasn’t caused recent warming is that, if it had, all the layers of the atmosphere should be heating up. Instead, data show that the upper atmosphere has actually cooled in recent decades — a hallmark of greenhouse warming .

So how about volcanoes? Eruptions cool the planet by injecting ash and aerosol particles into the atmosphere that reflect sunlight. We’ve observed this effect in the years following large eruptions. There are also some notable historical examples, like when Iceland’s Laki volcano erupted in 1783, causing widespread crop failures in Europe and beyond, and the “ year without a summer ,” which followed the 1815 eruption of Mount Tambora in Indonesia.

Since volcanoes mainly act as climate coolers, they can’t really explain recent warming. However, scientists say that they may also have contributed slightly to rising temperatures in the early 20th century. That’s because there were several large eruptions in the late 1800s that cooled the planet, followed by a few decades with no major volcanic events when warming caught up. During the second half of the 20th century, though, several big eruptions occurred as the planet was heating up fast. If anything, they temporarily masked some amount of human-caused warming.

The second way volcanoes can impact climate is by emitting carbon dioxide. This is important on time scales of millions of years — it’s what keeps the planet habitable (see Question 5 for more on the greenhouse effect). But by comparison to modern anthropogenic emissions, even big eruptions like Krakatoa and Mount St. Helens are just a drop in the bucket. After all, they last only a few hours or days, while we burn fossil fuels 24-7. Studies suggest that, today, volcanoes account for 1 to 2 percent of total CO2 emissions.

When a big snowstorm hits the United States, climate denialists can try to cite it as proof that climate change isn’t happening. In 2015, Senator James Inhofe, an Oklahoma Republican, famously lobbed a snowball in the Senate as he denounced climate science. But these events don’t actually disprove climate change.

While there have been some memorable storms in recent years, winters are actually warming across the world. In the United States, average temperatures in December, January and February have increased by about 2.5 degrees this century.

On the flip side, record cold days are becoming less common than record warm days. In the United States, record highs now outnumber record lows two-to-one . And ever-smaller areas of the country experience extremely cold winter temperatures . (The same trends are happening globally.)

So what’s with the blizzards? Weather always varies, so it’s no surprise that we still have severe winter storms even as average temperatures rise. However, some studies suggest that climate change may be to blame. One possibility is that rapid Arctic warming has affected atmospheric circulation, including the fast-flowing, high-altitude air that usually swirls over the North Pole (a.k.a. the Polar Vortex ). Some studies suggest that these changes are bringing more frigid temperatures to lower latitudes and causing weather systems to stall , allowing storms to produce more snowfall. This may explain what we’ve experienced in the U.S. over the past few decades, as well as a wintertime cooling trend in Siberia , although exactly how the Arctic affects global weather remains a topic of ongoing scientific debate .

Climate change may also explain the apparent paradox behind some of the other places on Earth that haven’t warmed much. For instance, a splotch of water in the North Atlantic has cooled in recent years, and scientists say they suspect that may be because ocean circulation is slowing as a result of freshwater streaming off a melting Greenland . If this circulation grinds almost to a halt, as it’s done in the geologic past, it would alter weather patterns around the world.

Not all cold weather stems from some counterintuitive consequence of climate change. But it’s a good reminder that Earth’s climate system is complex and chaotic, so the effects of human-caused changes will play out differently in different places. That’s why “global warming” is a bit of an oversimplification. Instead, some scientists have suggested that the phenomenon of human-caused climate change would more aptly be called “ global weirding .”

Extreme weather and natural disasters are part of life on Earth — just ask the dinosaurs. But there is good evidence that climate change has increased the frequency and severity of certain phenomena like heat waves, droughts and floods. Recent research has also allowed scientists to identify the influence of climate change on specific events.

Let’s start with heat waves . Studies show that stretches of abnormally high temperatures now happen about five times more often than they would without climate change, and they last longer, too. Climate models project that, by the 2040s, heat waves will be about 12 times more frequent. And that’s concerning since extreme heat often causes increased hospitalizations and deaths, particularly among older people and those with underlying health conditions. In the summer of 2003, for example, a heat wave caused an estimated 70,000 excess deaths across Europe. (Human-caused warming amplified the death toll .)

Climate change has also exacerbated droughts , primarily by increasing evaporation. Droughts occur naturally because of random climate variability and factors like whether El Niño or La Niña conditions prevail in the tropical Pacific. But some researchers have found evidence that greenhouse warming has been affecting droughts since even before the Dust Bowl . And it continues to do so today. According to one analysis , the drought that afflicted the American Southwest from 2000 to 2018 was almost 50 percent more severe because of climate change. It was the worst drought the region had experienced in more than 1,000 years.

Rising temperatures have also increased the intensity of heavy precipitation events and the flooding that often follows. For example, studies have found that, because warmer air holds more moisture, Hurricane Harvey, which struck Houston in 2017, dropped between 15 and 40 percent more rainfall than it would have without climate change.

It’s still unclear whether climate change is changing the overall frequency of hurricanes, but it is making them stronger . And warming appears to favor certain kinds of weather patterns, like the “ Midwest Water Hose ” events that caused devastating flooding across the Midwest in 2019 .

It’s important to remember that in most natural disasters, there are multiple factors at play. For instance, the 2019 Midwest floods occurred after a recent cold snap had frozen the ground solid, preventing the soil from absorbing rainwater and increasing runoff into the Missouri and Mississippi Rivers. These waterways have also been reshaped by levees and other forms of river engineering, some of which failed in the floods.

Wildfires are another phenomenon with multiple causes. In many places, fire risk has increased because humans have aggressively fought natural fires and prevented Indigenous peoples from carrying out traditional burning practices. This has allowed fuel to accumulate that makes current fires worse .

However, climate change still plays a major role by heating and drying forests, turning them into tinderboxes. Studies show that warming is the driving factor behind the recent increases in wildfires; one analysis found that climate change is responsible for doubling the area burned across the American West between 1984 and 2015. And researchers say that warming will only make fires bigger and more dangerous in the future.

It depends on how aggressively we act to address climate change. If we continue with business as usual, by the end of the century, it will be too hot to go outside during heat waves in the Middle East and South Asia . Droughts will grip Central America, the Mediterranean and southern Africa. And many island nations and low-lying areas, from Texas to Bangladesh, will be overtaken by rising seas. Conversely, climate change could bring welcome warming and extended growing seasons to the upper Midwest , Canada, the Nordic countries and Russia . Farther north, however, the loss of snow, ice and permafrost will upend the traditions of Indigenous peoples and threaten infrastructure.

It’s complicated, but the underlying message is simple: unchecked climate change will likely exacerbate existing inequalities . At a national level, poorer countries will be hit hardest, even though they have historically emitted only a fraction of the greenhouse gases that cause warming. That’s because many less developed countries tend to be in tropical regions where additional warming will make the climate increasingly intolerable for humans and crops. These nations also often have greater vulnerabilities, like large coastal populations and people living in improvised housing that is easily damaged in storms. And they have fewer resources to adapt, which will require expensive measures like redesigning cities, engineering coastlines and changing how people grow food.

Already, between 1961 and 2000, climate change appears to have harmed the economies of the poorest countries while boosting the fortunes of the wealthiest nations that have done the most to cause the problem, making the global wealth gap 25 percent bigger than it would otherwise have been. Similarly, the Global Climate Risk Index found that lower income countries — like Myanmar, Haiti and Nepal — rank high on the list of nations most affected by extreme weather between 1999 and 2018. Climate change has also contributed to increased human migration, which is expected to increase significantly .

Even within wealthy countries, the poor and marginalized will suffer the most. People with more resources have greater buffers, like air-conditioners to keep their houses cool during dangerous heat waves, and the means to pay the resulting energy bills. They also have an easier time evacuating their homes before disasters, and recovering afterward. Lower income people have fewer of these advantages, and they are also more likely to live in hotter neighborhoods and work outdoors, where they face the brunt of climate change.

These inequalities will play out on an individual, community, and regional level. A 2017 analysis of the U.S. found that, under business as usual, the poorest one-third of counties, which are concentrated in the South, will experience damages totaling as much as 20 percent of gross domestic product, while others, mostly in the northern part of the country, will see modest economic gains. Solomon Hsiang, an economist at University of California, Berkeley, and the lead author of the study, has said that climate change “may result in the largest transfer of wealth from the poor to the rich in the country’s history.”

Even the climate “winners” will not be immune from all climate impacts, though. Desirable locations will face an influx of migrants. And as the coronavirus pandemic has demonstrated, disasters in one place quickly ripple across our globalized economy. For instance, scientists expect climate change to increase the odds of multiple crop failures occurring at the same time in different places, throwing the world into a food crisis .

On top of that, warmer weather is aiding the spread of infectious diseases and the vectors that transmit them, like ticks and mosquitoes . Research has also identified troubling correlations between rising temperatures and increased interpersonal violence , and climate change is widely recognized as a “threat multiplier” that increases the odds of larger conflicts within and between countries. In other words, climate change will bring many changes that no amount of money can stop. What could help is taking action to limit warming.

One of the most common arguments against taking aggressive action to combat climate change is that doing so will kill jobs and cripple the economy. But this implies that there’s an alternative in which we pay nothing for climate change. And unfortunately, there isn’t. In reality, not tackling climate change will cost a lot , and cause enormous human suffering and ecological damage, while transitioning to a greener economy would benefit many people and ecosystems around the world.

Let’s start with how much it will cost to address climate change. To keep warming well below 2 degrees Celsius, the goal of the Paris Climate Agreement, society will have to reach net zero greenhouse gas emissions by the middle of this century. That will require significant investments in things like renewable energy, electric cars and charging infrastructure, not to mention efforts to adapt to hotter temperatures, rising sea-levels and other unavoidable effects of current climate changes. And we’ll have to make changes fast.

Estimates of the cost vary widely. One recent study found that keeping warming to 2 degrees Celsius would require a total investment of between $4 trillion and $60 trillion, with a median estimate of $16 trillion, while keeping warming to 1.5 degrees Celsius could cost between $10 trillion and $100 trillion, with a median estimate of $30 trillion. (For reference, the entire world economy was about $88 trillion in 2019.) Other studies have found that reaching net zero will require annual investments ranging from less than 1.5 percent of global gross domestic product to as much as 4 percent . That’s a lot, but within the range of historical energy investments in countries like the U.S.

Now, let’s consider the costs of unchecked climate change, which will fall hardest on the most vulnerable. These include damage to property and infrastructure from sea-level rise and extreme weather, death and sickness linked to natural disasters, pollution and infectious disease, reduced agricultural yields and lost labor productivity because of rising temperatures, decreased water availability and increased energy costs, and species extinction and habitat destruction. Dr. Hsiang, the U.C. Berkeley economist, describes it as “death by a thousand cuts.”

As a result, climate damages are hard to quantify. Moody’s Analytics estimates that even 2 degrees Celsius of warming will cost the world $69 trillion by 2100, and economists expect the toll to keep rising with the temperature. In a recent survey , economists estimated the cost would equal 5 percent of global G.D.P. at 3 degrees Celsius of warming (our trajectory under current policies) and 10 percent for 5 degrees Celsius. Other research indicates that, if current warming trends continue, global G.D.P. per capita will decrease between 7 percent and 23 percent by the end of the century — an economic blow equivalent to multiple coronavirus pandemics every year. And some fear these are vast underestimates .

Already, studies suggest that climate change has slashed incomes in the poorest countries by as much as 30 percent and reduced global agricultural productivity by 21 percent since 1961. Extreme weather events have also racked up a large bill. In 2020, in the United States alone, climate-related disasters like hurricanes, droughts, and wildfires caused nearly $100 billion in damages to businesses, property and infrastructure, compared to an average of $18 billion per year in the 1980s.

Given the steep price of inaction, many economists say that addressing climate change is a better deal . It’s like that old saying: an ounce of prevention is worth a pound of cure. In this case, limiting warming will greatly reduce future damage and inequality caused by climate change. It will also produce so-called co-benefits, like saving one million lives every year by reducing air pollution, and millions more from eating healthier, climate-friendly diets. Some studies even find that meeting the Paris Agreement goals could create jobs and increase global G.D.P . And, of course, reining in climate change will spare many species and ecosystems upon which humans depend — and which many people believe to have their own innate value.

The challenge is that we need to reduce emissions now to avoid damages later, which requires big investments over the next few decades. And the longer we delay, the more we will pay to meet the Paris goals. One recent analysis found that reaching net-zero by 2050 would cost the U.S. almost twice as much if we waited until 2030 instead of acting now. But even if we miss the Paris target, the economics still make a strong case for climate action, because every additional degree of warming will cost us more — in dollars, and in lives.

Veronica Penney contributed reporting.

Illustration photographs by Esther Horvath, Max Whittaker, David Maurice Smith and Talia Herman for The New York Times; Esther Horvath/Alfred-Wegener-Institut

An earlier version of this article misidentified the authors of The Debunking Handbook. It was written by social scientists who study climate communication, not a team of climate scientists.

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Essay on Greenhouse Effect: Causes, Problems, Effects and Prevention

The process by which radiation from a planet’s atmosphere warms its surface to a temperature which exceeds the normal temperature of the planet is called greenhouse effect. If a planet’s atmosphere contains greenhouse gases, the atmosphere will radiate the energy in various directions. Some part of this radiation will be towards the surface, making it warm. The downward component of the radiation, which is the strength of the greenhouse effect will depend on the atmosphere’s temperature and amount of greenhouse gases present in the atmosphere.

The earth’s atmosphere is warmed by absorbing infrared thermal radiation from the sun. The greenhouse gases which are present in the atmosphere radiate energy, some of which is directed to the surface and lower atmosphere. The mechanism which produces this difference between the actual surface temperature and effective temperature is due to the temperature, knows as greenhouse effect.

The natural greenhouse effect of the earth is critical to support life. Human activities such as burning the fossil fuels and clearing the forests have made an intense impact on natural greenhouse effect, leading to global warming.

History of Greenhouse Effect

The term greenhouse effect was first used by atmospheric scientists in early 1800s. The existence of greenhouse effect was brought up by Joseph Fourier in 1824. In 1896, the effect was fully qualified by Svante Arrhenius, who made the first quantitative prediction of global warming because of a hypothetical doubling of atmospheric carbon dioxide. At the time, it was used to describe the naturally occurring functions of greenhouse gases present in the atmosphere, and did not have any negative subtexts. It was not until the mid 1950s that greenhouse effect was teamed with concern for climate change.

Greenhouse gases that cause Greenhouse Effect

The major gases which contribute to the greenhouse effect on earth are as follows:-

Water vapor 36-70%
Carbon dioxide 9-26%
Methane 4-9%

The below mentioned activities release gases which prove to be harmful for the planet. Following are the six major greenhouses which play a lead role in the greenhouse effect and global warming:-

1. Carbon dioxide (CO2)

It is a naturally occurring gas, produced by living organisms and fermentation. Carbon dioxide which is emitted from fuel burning is responsible for approx 87% of global warming, and has alarmingly increased by 27% since the industrial revolution.

2. Methane (CH4)

Methane is a naturally occurring inflammable gas which is produced by decomposition of organic matters and geological coal formations. The landfills hole the major credit to release methane, which adds up into the atmosphere and leads the global warming.

3. Nitrogen oxides (NOx)

Nitrogen oxides are naturally occurring from microbial action present in the soil. It is also produced by burning of fuels. Due to the increased use of nitrogen based fertilizers and catalytic converters in automobiles, the production of nitrogen oxides has raised, thus disturbing the ecosystem balance.

4. Hydrofluorocarbon gases (HFCs)

Chlorofluorocarbons (CFCs), coolant, cleaning and propellant gases were blacklisted internationally due to its harmful effect on the ozone layer. HFCs also play a crucial part in global warming, and are 4,000 to 10,000 times more harmful than carbon dioxide.

5. Sulphur hexafluoride (SF6)

Very low atmospheric concentration can make it a good test gas for gas concentration monitors. SF6 is a man-made gas used in water leakage detection for cable cooling systems and insulating materials for high voltage equipment.

6. Perfluorocrbons (PFCs)

PFCs are man-made replacement gases for CFCs, but they also result as a by-product of aluminum smelting. They are also used as a purging agent for semi conductor manufacturing. They cause severe damage to the atmosphere too.

What does increased greenhouse gases indicate?

The increase in greenhouse gases directly increases the heat on the planet’s surface and lower atmosphere. It has a dangerous effect as it can reduce or even create holes in the ozone layer. Due to this, harmful rays such as ultra violet rays can seep in though the thin areas and cause damage on earth.

What are the causes of greenhouse effect?

1. burning the fossil fuels.

Fossil fuels such as coal, natural gas and oil are an integral part of our lives, the elements which play a vital role in daily routines. The most important use of fossil fuels occurs in producing electricity and transportation. On burning the fossil fuels, the carbon dioxide stored inside them is released, which combines with oxygen in the air, resulting in production of carbon dioxide. As the population is increasing, the numbers of vehicles have made a high leap too. Due to this, the pollution has increased in the atmosphere. As these vehicles run, carbon dioxide is released, which is one of the main gases responsible for increase in greenhouse effect.

Electricity related emissions are high because we are still dependant on coal for generating electricity, which releases a huge amount of carbon dioxide into the atmosphere. Since it is the primary source of generating electricity, the loss of fossil fuels is massive, due to which the global warming has increased.

2. Deforestation

A major section of the land on our earth is covered by the forests. They are very important for a sustainable life on earth, as plants give out oxygen and inhale the carbon dioxide. Thus, the ecosystem is balanced due to the presence of trees. Sadly, large scale development of the urban landscapes has resulted in depletion of green cover of the earth. Forests are now being burnt down or chopped off to build concrete buildings instead. On burning the wood, the stored carbon is converted back to carbon dioxide, which adds up into the atmosphere, increasing the pollution.

3. Industrial waste and landfills

Various industries which are involved in cement production, fertilizers, extraction of oil, coal mining activities etc produce harmful greenhouse gases. Also, landfills filled with garbage produce carbon dioxide and methane, which play a major role in the greenhouse effect.

4. Population rise

Increase in population over the decades has led to high demand for food, clothing and shelter. Machines used in our daily lives such as air conditioners also exhale harmful gases, which contribute to the greenhouse effect. Also, more number of people means more usage of fossil fuels, which has made the situations much worse.

What are the harmful effects of greenhouse effect?

The adverse effects of greenhouse effect are alarming. They are already being experienced on the earth now, and can go much adverse changes in the near future. The major harmful effects of greenhouse effect are listed below:

The sea levels will rise. There is more than 5,773,000 cubic miles of water present in form of ice caps, glaciers and permanent snow. According to the National Snow and Ice Data Center, if all of the glaciers met, the sea level would rise by 230 feet! This will not happen all at once, but the levels will rise certainly, submerging the low-lying areas.
The balance of the global ecosystem will be affected. The fresh water stored in the ice caps will desalinate the ocean as they melt. The desalination in the gulf current will play a negative impact on the ocean currents, which regulate temperatures. It will be difficult to draw a pattern of warming and cooling in some areas.
Warmer water and stronger hurricanes will be more frequent than now. Due to the rise in oceans’ temperature, the probability of frequent and stronger hurricanes may also become a threat.
Weather patterns will continue to change. Most of the regions that are currently subjected to droughts will face much challenging conditions. The wet region will get wetter too. Mountain glaciers and snow caps will further shrink which will jeopardize many water supply systems. These negative changes have already begun to show their impact in some parts of the world.
Ecosystems will be stressed due the impact of greenhouse effect and global warming. Flora and fauna will be massively affected. The animals which cannot adapt to the climatic changes will extinct over the time, thus misbalancing the ecosystem balance. A variety of pests and tropical diseases are expected to sprout in the warmer regions. Valuable species especially in the arctic will be the worst affected.

Evidence to the changes in earth’s climate: Global Warming

The effects of greenhouse effect and global warming have already started showing up in some parts of the world. Situations are predicted to get much worse. Some of the observations recorded by the Intergovernmental Panel on Climate Change (IPCC) are as follows: -

Eleven out of twelve warmest years since 1850 occurred between 1996 and 2006. Average global temperatures have risen by approximately 0.74C between 1906 and 2005. This rise in temperature is widespread throughout the world, but higher at the northern latitudes.
Sea levels have increased during the same period. Since 1961, the average rate has been 1.8 mm per year, but has now further increased to 3.1 mm per year since 1993.
Some of the climate changes agencies from the United States have reported that the oceans all over the world are getting warmer at a rate much higher than predicted. The warming has occurred approximately 50% faster over that last century, than it was calculated previously.

A number of human activities contribute to the greenhouse effect, which has brought us to the alarming situations today. If continued without taking precautions to save the earth, the situations are going to be worse. Some of the human activities which produce greenhouse gases are as follows: -

Fuel combustion
Vehicle transport and automobiles
Energy industries
Use of oil and natural gas
Metal production manufacturing industries and construction
Fugitive emissions from fuels
Mineral products
Chemical industries
Production of halocarbons
Solvent and other product use
Consumption of halocarbons and sulphur hexafluoride
Production of halocarbons and sulphur hexafluoride
Enteric fermentation
Rice cultivation
Agricultural soils
Prescribes burning of savannas
Solid waste disposal on land
Wastewater handling
Waste incineration
Field burning of agricultural residues

What preventive should be taken against greenhouse effect?

It would not be late today if we take an initiative to make the earth a reliable place to live in. to reduce the harmful effects of greenhouse gases on the earth and atmosphere, change must be brought in our daily routine and lifestyles. Here are some of the best suggestive steps to keep in mind to reduce greenhouse gas emissions:-

Reduce, Reuse, Recycle Following the three Rs in your daily life can make a difference too. Buying products with minimal packaging will help in reducing waste. Through recycling half of your household waste, 2,400 pounds of carbon dioxide can be saved from adding up in the atmosphere.
By adding insulation to the walls, installing caulking or weather stripping around doors and windows.
Lower the heat while sleeping and keep the temperature moderate all the time.
Installing a programmable thermostat can save a large amount of carbon dioxide from being released. By setting it just 2 degrees lower during winter and higher in summer can save approx. 2,000 pounds of carbon dioxide each year.
Replace the light bulbs with Compact Fluorescent Lights It is better to use compact fluorescent light (CFL) than the usual light bulbs. By replacing just one 60-watt incandescent light bulb with a CFL, over $30 will be saved over the life of the bulb. Also, the CFL gives off 70 percent less heat than the light bulbs and lasts 10 times longer than them too.
Drive less and drive smart Walking and biking are a great form of exercise. Not only they will keep you fit, but also make your contribution towards saving the planet, since less driving means lesser emissions. Every gallon of gas saved will keep 20 pounds of carbon dioxide away from the atmosphere.
Use less hot water Set your water heater at 120 degrees and wrap it in an insulating blanket if it is 15 years old. Also, use low flow showerheads to save hot water and approx 350 pounds of carbon dioxide every year.
Buy energy efficient products Home appliances now come in a wide range of energy efficient models, and compact fluorescent bulbs are designed to use much lesser amount of energy than the regular light bulbs.
Plant a tree Trees are the best solution to fight against the greenhouse effect and global warming. Not only they inhale carbon dioxide and release oxygen for us, plantation will also help in restoring the disturbed ecological balance.
Use the ‘off’ switch Save electricity and reduce global warming by using power only when you need it. Make a habit to switch off lights, television, computer and other electronic devices when they are not in use. Turn off the water tap when you do not need the water. These simple steps will help you in reducing the energy usage and burning of fossil fuels. Less energy usage means less dependence on fossil fuels, which on burning contribute to the harmful greenhouse effect.

Greenhouse effect Essay Conclusion

Greenhouse effect and global warming are the biggest threat to human race and the biggest environmental challenge of 21st century that we need to tackle. It is important for all citizens to become fully aware of the causes and harmful consequences of greenhouse effect and global warming. The main culprits of greenhouse effect and global warming is the growing emission of harmful gases such as Methane, carbon dioxide and carbon monoxide resulting from emissions of industrial activities, incomplete combustion of petrol and diesel from vehicles as well as growing emissions of CFCs from air conditioners. It is important for individuals to choose greener alternatives such as cycling, hybrid clean fuels and for industries and governments to choose environmental friendly production methods and energy sources. Immediate action on this greenhouse effect and global warming is necessary to tackle this environmental problem.

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Global warming is not something to take lightly. The oceans are warming, the polar ice caps are melting, and greenhouse gas levels are at an all-time high. These are just some of the things that the claims-makers for the global warming cause have said. The science has proven them right. So, the ultimate claim is that humans are a large factor in the increased rate of global warming. There are claims-makers of all kinds fighting about whether that is true or not. The solutions proposed deal with a cleaner world, while the deniers will opt to do nothing. This issue has turned political, and it seems like nothing gets done until someone who believes in global warming is in charge. Right now, that is not the case. This issue will continue to get worse until there is no turning back. Hopefully society can come to a consensus to try and inhibit global warming. This is the only way to keep the place we live healthy.

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Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base (1992)

Chapter: 18 conclusions, 18 conclusions.

Despite (1) uncertainties in the interpretation of the climate record, (2) severe limitations on the predictive capabilities of the models, (3) masking effects of the natural variability of the models, and (4) masking effects of the natural variability of the climatic system, there is clear evidence and wide agreement among members of the atmospheric sciences community and the members of this panel about several basic facts:

1. The atmospheric concentration of CO 2 has increased by at least 25 percent since preindustrial times and is currently increasing at about 0.5 percent per year.

2. The atmospheric concentration of CH 4 has doubled during that period and is increasing at about 0.9 percent per year.

3. Atmospheric concentrations of CFCs, which are a result of industrial activities and have been released into the atmosphere in quantity only since World War II, are currently increasing at about 4 percent per year.

4. Items 1, 2, and 3 are primarily direct consequences of human activities.

5. Current interpretations of temperature records reveal that the global average temperature has increased between 0.3° and 0.6°C (0.5° and 1.1°F) during the last century.

As a result, the panel concludes that there is a reasonable chance of the following:

1. In the absence of greater human effort to the contrary, greenhouse gas concentrations equivalent to a doubling of the preindustrial level of CO 2 will occur by the middle of the next century.

2. The sensitivity of the climatic system to greenhouse gases is such that the equivalent of doubling CO 2 could ultimately increase the average global temperature by somewhere between 1° and 5°C (1.8° and 9°F). This range is slightly broader than those used by other groups. Prudence dictates that the uncertainties in the science base call for wider rather than narrower ranges of projected temperatures for use in policy choices. In the panel's view, this range expresses much less unwarranted faith in the numbers produced by GCMs than does a narrow range.

3. The transfer of heat to the deep ocean occurs more slowly than the transfer of heat within the atmosphere or within the upper layers of the ocean. The resulting transient period, or ''lag," means that the global average surface temperature at any time is lower than the temperature that would prevail after all the redistribution had been completed. The greater the response, the faster the warming; however, the increase in the warming rate is less than proportional to the climate sensitivity, so it will take longer for the full warming to appear. At the time of equivalent CO 2 doubling, for example, the global average surface temperature may be as little as one-half the ultimate equilibrium temperature associated with those concentrations.

4. A rise in sea level may accompany global warming, possibly in the range of 0 to 60 cm (0 to 24 inches) for the temperature range listed above. This range allows for uncertainties in estimates of current sea level change. Zero is included in the range not only because of the uncertainties but also because precipitation in the Antarctic functions to partially offset thermal expansion.

5. A wide range of potentially amplifying or moderating feedbacks have been suggested that involve atmospheric composition and climatic changes. Examples include increased CH 4 emissions as the permafrost melts, increased carbon uptake by plants at higher CO 2 concentrations, increased summer drying of continental interiors, increased continental precipitation in winter, increased hurricane frequency and/or intensity, and many more potential changes and surprises. Convincing quantitative demonstrations and confirmations of these and other potential changes are lacking, and there is no evidence that any of the changes are imminent, but none of them are precluded.

Global warming continues to gain importance on the international agenda and calls for action are heightening. Yet, there is still controversy over what must be done and what is needed to proceed.

Policy Implications of Greenhouse Warming describes the information necessary to make decisions about global warming resulting from atmospheric releases of radiatively active trace gases. The conclusions and recommendations include some unexpected results. The distinguished authoring committee provides specific advice for U.S. policy and addresses the need for an international response to potential greenhouse warming.

It offers a realistic view of gaps in the scientific understanding of greenhouse warming and how much effort and expense might be required to produce definitive answers.

The book presents methods for assessing options to reduce emissions of greenhouse gases into the atmosphere, offset emissions, and assist humans and unmanaged systems of plants and animals to adjust to the consequences of global warming.

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Essay on Greenhouse Effect for Students
600 Words Essay on Greenhouse Effect. A Greenhouse, as the term suggests, is a structure made of glass which is designed to trap heat inside. Thus, even on cold chilling winter days, there is warmth inside it. Similarly, Earth also traps energy from the Sun and prevents it from escaping back. The greenhouse gases or the molecules present in the ...
Conclusion
C ONCLUSION. This document explains that there are well-understood physical mechanisms by which changes in the amounts of greenhouse gases cause climate changes. It discusses the evidence that the concentrations of these gases in the atmosphere have increased and are still increasing rapidly, that climate change is occurring, and that most of ...
Greenhouse Effect
greenhouse effect. phenomenon where gases allow sunlight to enter Earth's atmosphere but make it difficult for heat to escape. greenhouse gas. gas in the atmosphere, such as carbon dioxide, methane, water vapor, and ozone, that absorbs solar heat reflected by the surface of the Earth, warming the atmosphere.
Greenhouse effect
greenhouse effect, a warming of Earth's surface and troposphere (the lowest layer of the atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air. Of those gases, known as greenhouse gases, water vapour has the largest effect.. The origins of the term greenhouse effect are unclear. French mathematician Joseph Fourier is sometimes given ...
The Greenhouse Effect and our Planet
The greenhouse effect happens when certain gases, which are known as greenhouse gases, accumulate in Earth's atmosphere. Greenhouse gases include carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2 O), ozone (O 3), and fluorinated gases.. Greenhouse gases allow the sun's light to shine onto Earth's surface, and then the gases, such as ozone, trap the heat that reflects back from ...
Greenhouse effect
The greenhouse effect occurs in the atmosphere, and is an essential part of How the Earth System Works. Click the image on the left to open the Understanding Global Change Infographic. Locate the greenhouse effect icon and identify other topics that cause changes to, or are affected by, the greenhouse effect.
8 Conclusions and Recommendations
CHAPTER EIGHT Conclusions and Recommendations B ecause impacts of climate change are already being observed in the United States and elsewhere in the world, and because impacts will increase in severity even if greenhouse gas (GHG) emissions are reduced substantially in the near term, the United States must improve its ability to adapt to ...
21.1: The Greenhouse Effect and Climate Change
The greenhouse effect also happens with the entire Earth. Of course, our planet is not surrounded by glass windows. Instead, the Earth is wrapped with an atmosphere that contains greenhouse gases (GHGs).Much like the glass in a greenhouse, GHGs allow incoming visible light energy from the sun to pass, but they block infrared radiation that is radiated from the Earth towards space (figure ...
Conclusion
Conclusion This document explains that there are well-understood physical mechanisms by which changes in the amounts of greenhouse gases cause climate changes. It discusses the evidence that the concentrations of these gases in the atmosphere have increased and are still increasing rapidly, that climate change is occurring, and that most of the ...
Greenhouse Effect
The "greenhouse effect" is a complicated process by which the earth is becoming progressively warmer. The earth is bathed in sunlight, some of it reflected back into space and some absorbed. If the absorption is not matched by radiation back into space, the earth will get warmer until the intensity of that radiation matches the incoming ...
The Science of Climate Change Explained: Facts, Evidence and Proof
Definitive answers to the big questions. For more than a century, scientists have understood the basic physics behind why greenhouse gases like carbon dioxide cause warming. These gases make up ...
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Definition. The greenhouse effect on Earth is defined as: "The infrared radiative effect of all infrared absorbing constituents in the atmosphere.Greenhouse gases (GHGs), clouds, and some aerosols absorb terrestrial radiation emitted by the Earth's surface and elsewhere in the atmosphere.": 2232 The enhanced greenhouse effect describes the fact that by increasing the concentration of GHGs in ...
Summary of Conclusions
Climate change will affect the basic elements of life for people around the world - access to water, food production, health, and the environment. Hundreds of millions of people could suffer hunger, water shortages and coastal flooding as the world warms. Using the results from formal economic models, the Review estimates that if we don't act ...
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Greenhouse Effect). They are very efficient in trapping heat into the atmosphere; therefore, it results in the greenhouse effect. The solar energy is absorbed by the earth's surface and then reflected back to the atmosphere as heat. Then as the heat goes out to space, greenhouse gases absorb a part of the heat.
Sample Essays
Greenhouse effect Essay Conclusion. Greenhouse effect and global warming are the biggest threat to human race and the biggest environmental challenge of 21st century that we need to tackle. It is important for all citizens to become fully aware of the causes and harmful consequences of greenhouse effect and global warming. The main culprits of ...
Questions and Answers About Greenhouse Warming
What is the "greenhouse effect"? In simplest terms, "greenhouse gases" let sunlight through to the earth's surface while trapping "outbound" radiation. This alters the radiative balance of the earth (see Figure A.1) and results in a warming of the earth's surface. ... The conclusions and recommendations include some unexpected results. The ...
Essay About Greenhouse Effect and Global Warming
Global warming occurs when carbon dioxide and other major pollutants in air and greenhouse gases accumulates in the atmosphere and daylight and radiation from earth surface gets absorbed. In normal cases, these radiations get transmitted into space—but the air pollutants last for a very longer time period in the atmosphere, enhancing the ...
Global Warming conclusion
Global Warming conclusion. Submitted by rdigregorio on Thu, 02/28/2019 - 12:04. Global warming is not something to take lightly. The oceans are warming, the polar ice caps are melting, and greenhouse gas levels are at an all-time high. These are just some of the things that the claims-makers for the global warming cause have said.
Elektrostal
Elektrostal , lit: Electric and Сталь , lit: Steel) is a city in Moscow Oblast, Russia, located 58 kilometers east of Moscow. Population: 155,196 ; 146,294 ...
File:Flag of Elektrostal (Moscow oblast).svg
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.A copy of the license is included in the section entitled GNU Free Documentation License.
18 Conclusions
Page 153. 18 Conclusions. Despite (1) uncertainties in the interpretation of the climate record, (2) severe limitations on the predictive capabilities of the models, (3) masking effects of the natural variability of the models, and (4) masking effects of the natural variability of the climatic system, there is clear evidence and wide agreement among members of the atmospheric sciences ...
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Elektrostal. Elektrostal ( Russian: Электроста́ль) is a city in Moscow Oblast, Russia. It is 58 kilometers (36 mi) east of Moscow. As of 2010, 155,196 people lived there.
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