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Fossil fuels – coal, oil and gas – are by far the largest contributor to global climate change, accounting for over 75 per cent of global greenhouse gas emissions and nearly 90 per cent of all carbon dioxide emissions. As greenhouse gas emissions blanket the Earth, they trap the sun’s heat. This leads to global warming and climate change. The world is now warming faster than at any point in recorded history. Warmer temperatures over time are changing weather patterns and disrupting the usual balance of nature. This poses many risks to human beings and all other forms of life on Earth. 

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Home — Essay Samples — Environment — Climate Change — Climate Change: Causes, Effects, and Solutions

Climate Change: Causes, Effects, and Solutions

• Categories: Climate Change

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Published: Jan 29, 2024

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Table of contents

Introduction, causes of climate change, effects of climate change, efforts to combat climate change, challenges and future outlook.

• Intergovernmental Panel on Climate Change (IPCC). " Climate Change 2021: The Physical Science Basis." IPCC Sixth Assessment Report, 2021. https://www.ipcc.ch/report/ar6/wg1/
• United Nations Framework Convention on Climate Change (UNFCCC). "The Paris Agreement." UNFCCC, 2015. https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement
• United Nations. "Sustainable Development Goals." United Nations, https://sdgs.un.org/goals

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Climate Change: Evidence and Causes: Update 2020 (2020)

Chapter: 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 the recent change is almost certainly due to emissions of greenhouse gases caused by human activities. Further climate change is inevitable; if emissions of greenhouse gases continue unabated, future changes will substantially exceed those that have occurred so far. There remains a range of estimates of the magnitude and regional expression of future change, but increases in the extremes of climate that can adversely affect natural ecosystems and human activities and infrastructure are expected.

Citizens and governments can choose among several options (or a mixture of those options) in response to this information: they can change their pattern of energy production and usage in order to limit emissions of greenhouse gases and hence the magnitude of climate changes; they can wait for changes to occur and accept the losses, damage, and suffering that arise; they can adapt to actual and expected changes as much as possible; or they can seek as yet unproven “geoengineering” solutions to counteract some of the climate changes that would otherwise occur. Each of these options has risks, attractions and costs, and what is actually done may be a mixture of these different options. Different nations and communities will vary in their vulnerability and their capacity to adapt. There is an important debate to be had about choices among these options, to decide what is best for each group or nation, and most importantly for the global population as a whole. The options have to be discussed at a global scale because in many cases those communities that are most vulnerable control few of the emissions, either past or future. Our description of the science of climate change, with both its facts and its uncertainties, is offered as a basis to inform that policy debate.

A CKNOWLEDGEMENTS

The following individuals served as the primary writing team for the 2014 and 2020 editions of this document:

• Eric Wolff FRS, (UK lead), University of Cambridge
• Inez Fung (NAS, US lead), University of California, Berkeley
• Brian Hoskins FRS, Grantham Institute for Climate Change
• John F.B. Mitchell FRS, UK Met Office
• Tim Palmer FRS, University of Oxford
• Benjamin Santer (NAS), Lawrence Livermore National Laboratory
• John Shepherd FRS, University of Southampton
• Keith Shine FRS, University of Reading.
• Susan Solomon (NAS), Massachusetts Institute of Technology
• Kevin Trenberth, National Center for Atmospheric Research
• John Walsh, University of Alaska, Fairbanks
• Don Wuebbles, University of Illinois

Staff support for the 2020 revision was provided by Richard Walker, Amanda Purcell, Nancy Huddleston, and Michael Hudson. We offer special thanks to Rebecca Lindsey and NOAA Climate.gov for providing data and figure updates.

The following individuals served as reviewers of the 2014 document in accordance with procedures approved by the Royal Society and the National Academy of Sciences:

• Richard Alley (NAS), Department of Geosciences, Pennsylvania State University
• Alec Broers FRS, Former President of the Royal Academy of Engineering
• Harry Elderfield FRS, Department of Earth Sciences, University of Cambridge
• Joanna Haigh FRS, Professor of Atmospheric Physics, Imperial College London
• Isaac Held (NAS), NOAA Geophysical Fluid Dynamics Laboratory
• John Kutzbach (NAS), Center for Climatic Research, University of Wisconsin
• Jerry Meehl, Senior Scientist, National Center for Atmospheric Research
• John Pendry FRS, Imperial College London
• John Pyle FRS, Department of Chemistry, University of Cambridge
• Gavin Schmidt, NASA Goddard Space Flight Center
• Emily Shuckburgh, British Antarctic Survey
• Gabrielle Walker, Journalist
• Andrew Watson FRS, University of East Anglia

The Support for the 2014 Edition was provided by NAS Endowment Funds. We offer sincere thanks to the Ralph J. and Carol M. Cicerone Endowment for NAS Missions for supporting the production of this 2020 Edition.

F OR FURTHER READING

For more detailed discussion of the topics addressed in this document (including references to the underlying original research), see:

• Intergovernmental Panel on Climate Change (IPCC), 2019: Special Report on the Ocean and Cryosphere in a Changing Climate [ https://www.ipcc.ch/srocc ]
• National Academies of Sciences, Engineering, and Medicine (NASEM), 2019: Negative Emissions Technologies and Reliable Sequestration: A Research Agenda [ https://www.nap.edu/catalog/25259 ]
• Royal Society, 2018: Greenhouse gas removal [ https://raeng.org.uk/greenhousegasremoval ]
• U.S. Global Change Research Program (USGCRP), 2018: Fourth National Climate Assessment Volume II: Impacts, Risks, and Adaptation in the United States [ https://nca2018.globalchange.gov ]
• IPCC, 2018: Global Warming of 1.5°C [ https://www.ipcc.ch/sr15 ]
• USGCRP, 2017: Fourth National Climate Assessment Volume I: Climate Science Special Reports [ https://science2017.globalchange.gov ]
• NASEM, 2016: Attribution of Extreme Weather Events in the Context of Climate Change [ https://www.nap.edu/catalog/21852 ]
• IPCC, 2013: Fifth Assessment Report (AR5) Working Group 1. Climate Change 2013: The Physical Science Basis [ https://www.ipcc.ch/report/ar5/wg1 ]
• NRC, 2013: Abrupt Impacts of Climate Change: Anticipating Surprises [ https://www.nap.edu/catalog/18373 ]
• NRC, 2011: Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia [ https://www.nap.edu/catalog/12877 ]
• Royal Society 2010: Climate Change: A Summary of the Science [ https://royalsociety.org/topics-policy/publications/2010/climate-change-summary-science ]
• NRC, 2010: America’s Climate Choices: Advancing the Science of Climate Change [ https://www.nap.edu/catalog/12782 ]

Much of the original data underlying the scientific findings discussed here are available at:

• https://data.ucar.edu/
• https://climatedataguide.ucar.edu
• https://iridl.ldeo.columbia.edu
• https://ess-dive.lbl.gov/
• https://www.ncdc.noaa.gov/
• https://www.esrl.noaa.gov/gmd/ccgg/trends/
• http://scrippsco2.ucsd.edu
• http://hahana.soest.hawaii.edu/hot/

Climate change is one of the defining issues of our time. It is now more certain than ever, based on many lines of evidence, that humans are changing Earth's climate. The Royal Society and the US National Academy of Sciences, with their similar missions to promote the use of science to benefit society and to inform critical policy debates, produced the original Climate Change: Evidence and Causes in 2014. It was written and reviewed by a UK-US team of leading climate scientists. This new edition, prepared by the same author team, has been updated with the most recent climate data and scientific analyses, all of which reinforce our understanding of human-caused climate change.

Scientific information is a vital component for society to make informed decisions about how to reduce the magnitude of climate change and how to adapt to its impacts. This booklet serves as a key reference document for decision makers, policy makers, educators, and others seeking authoritative answers about the current state of climate-change science.

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Climate Change: Causes and Effects Cause and Effect Essay

Climate is a term used to denote the patterns of weather occurring in particular regions of the globe. Climate change denotes the long-term changes in weather patterns over extended time periods. In modern times, the term has been used to describe the rapid climatic changes as a result of global warming.

Climate change thus denotes fluctuations in the statistical properties of weather patterns when considered over periods longer than 10 years. As such, short fluctuations such as El-Niño, cannot be considered as climate change. There is a general consensus amongst the scientific community that the current increase in climate change is mainly due to human factors and the result of this climate change might have catastrophic consequences.

There are mainly two factors that influence climate change: Natural and human factors. First, under natural causes variations in the radiation outputs of the sun has been found to have a considerable effect on the earth’s climatic conditions.

According to scientists, solar output variation of 1% per century would result in a variation of the earth’s average temperature ranging between 0.5 and 1.0 0 Celsius (USNAS). Solar output causes surface heat fluctuations due to changes in heat absorption and radiation by the earth surface. Secondly, volcanic eruptions have been linked to climate changes. Volcanic eruptions of sufficient magnitude have the ability to alter the climate system of the whole world.

Volcanic ashes, dust and gases released during volcanic eruptions creates a blanket that obstructs solar radiation from the sun thus reducing the earth’s surface temperatures. The last important natural factor is orbital variations. Orbital variations lead to changes in the levels of solar radiation reaching the earth mainly due to the position of the sun and the distance between the earth and the sun during each particular orbital cycle.

During the 19 th century, the industrial revolution commenced resulting in the extensive use of fossil fuel for energy purposes. The industrial revolution also resulted in human migration from rural areas to cities with people looking for a better life. Land that was previously filled with vegetation was now cleared to make room for buildings and roads.

Natural resources were extensively consumed for industries, construction and transport. As a result, the levels of atmospheric greenhouse gases increased considerably. Greenhouse gases are an integral part of the earth’s climatic system as they help in warming up the earth’s surface. The increased emission of greenhouse gases (especially carbon dioxide) has led to the accelerated warming of the earth’s surface (global warming).

Methane, emitted from oil drilling, waste dumps and landfills, is also another important greenhouse gas whose content has been continually increasing. The extensive use of fertilizer has also led to the rise in nitrous oxide emission, another important greenhouse gas. These are all responsible for global warming and the subsequent climate change.

Scientists from around the world have identified several impacts of climate change. First, climate change has resulted in the gradual increase in ocean levels (Trenberth, 244). This has mainly been attributed to expansion of warmer ocean water and the melting of polar glacier ice. Rising sea waters affects coral reefs, coastal communities and wetlands mainly through flooding and encroachment of the sea into dry land. Changes in climate have also led to changes in weather patterns.

The rise in surface temperatures has resulted into heavy rainfalls that cause flooding in many areas of the world. Increase in surface temperatures has also resulted into severe and prolonged drought in other parts of the world. Climate change has also resulted in the increase of occurrence and magnitude of extreme climatic events such as tsunamis and hurricanes. Changes in climate lead to changes in ocean currents which might result in the occurrence of such events.

Over the course of earth’s history, various instances of climate changes have occurred some more extensive than others e.g. the ice age. However, during the turn of the 20 th century, it has been noted that the rate of climate change has been increasing. Many scientists believe that this increase is mainly due to pollution of the air and the environment due to human activities e.g. industrialization and deforestation. Climate change has had several impacts on the earth’s weather system.

The increase in natural disasters such as cyclones, hurricanes and typhoons can be attributed to global warming. In order to mitigate the effects of climate change, it is important for people to realize the part they play in climate change and take effective measures. Various governments and institutions have instituted greenhouse emission restrictions in order to address this issue.

Campaigns aimed at educating individuals on the appropriate strategies in reducing greenhouse emissions have also been instituted. We are all part of the world and it is in our best interest to undertake all necessary measures to curb climate change.

Works Cited

Trenberth, Kevin. IPCC Fourth Assessment Report . New York, NY: Cambridge University Press, 2007

United States National Academy of Sciences (USNAS). “Understanding and Responding to Climate Change”. 2008. Web.

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IvyPanda. (2023, December 22). Climate Change: Causes and Effects. https://ivypanda.com/essays/climate-change-causes-and-effects/

"Climate Change: Causes and Effects." IvyPanda , 22 Dec. 2023, ivypanda.com/essays/climate-change-causes-and-effects/.

IvyPanda . (2023) 'Climate Change: Causes and Effects'. 22 December.

IvyPanda . 2023. "Climate Change: Causes and Effects." December 22, 2023. https://ivypanda.com/essays/climate-change-causes-and-effects/.

1. IvyPanda . "Climate Change: Causes and Effects." December 22, 2023. https://ivypanda.com/essays/climate-change-causes-and-effects/.

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The Basics of Climate Change

Greenhouse gases affect Earth’s energy balance and climate

The Sun serves as the primary energy source for Earth’s climate. Some of the incoming sunlight is reflected directly back into space, especially by bright surfaces such as ice and clouds, and the rest is absorbed by the surface and the atmosphere. Much of this absorbed solar energy is re-emitted as heat (longwave or infrared radiation). The atmosphere in turn absorbs and re-radiates heat, some of which escapes to space. Any disturbance to this balance of incoming and outgoing energy will affect the climate. For example, small changes in the output of energy from the Sun will affect this balance directly.

If all heat energy emitted from the surface passed through the atmosphere directly into space, Earth’s average surface temperature would be tens of degrees colder than today. Greenhouse gases in the atmosphere, including water vapour, carbon dioxide, methane, and nitrous oxide, act to make the surface much warmer than this because they absorb and emit heat energy in all directions (including downwards), keeping Earth’s surface and lower atmosphere warm [Figure B1]. Without this greenhouse effect, life as we know it could not have evolved on our planet. Adding more greenhouse gases to the atmosphere makes it even more effective at preventing heat from escaping into space. When the energy leaving is less than the energy entering, Earth warms until a new balance is established.

Greenhouse gases emitted by human activities alter Earth’s energy balance and thus its climate. Humans also affect climate by changing the nature of the land surfaces (for example by clearing forests for farming) and through the emission of pollutants that affect the amount and type of particles in the atmosphere.

Scientists have determined that, when all human and natural factors are considered, Earth’s climate balance has been altered towards warming, with the biggest contributor being increases in CO 2 .

Figure b1. Greenhouse gases in the atmosphere, including water vapour, carbon dioxide, methane, and nitrous oxide, absorb heat energy and emit it in all directions (including downwards), keeping Earth’s surface and lower atmosphere warm. Adding more greenhouse gases to the atmosphere enhances the effect, making Earth’s surface and lower atmosphere even warmer. Image based on a figure from US EPA.

Human activities have added greenhouse gases to the atmosphere

The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased significantly since the Industrial Revolution began. In the case of carbon dioxide, the average concentration measured at the Mauna Loa Observatory in Hawaii has risen from 316 parts per million (ppm) in 1959 (the first full year of data available) to more than 411 ppm in 2019 [Figure B2]. The same rates of increase have since been recorded at numerous other stations worldwide. Since preindustrial times, the atmospheric concentration of CO 2  has increased by over 40%, methane has increased by more than 150%, and nitrous oxide has increased by roughly 20%. More than half of the increase in CO 2  has occurred since 1970. Increases in all three gases contribute to warming of Earth, with the increase in CO 2  playing the largest role. See page B3 to learn about the sources of human emitted greenhouse gases.  Learn about the sources of human emitted greenhouse gases.

Scientists have examined greenhouse gases in the context of the past. Analysis of air trapped inside ice that has been accumulating over time in Antarctica shows that the CO 2  concentration began to increase significantly in the 19th century [Figure B3], after staying in the range of 260 to 280 ppm for the previous 10,000 years. Ice core records extending back 800,000 years show that during that time, CO 2  concentrations remained within the range of 170 to 300 ppm throughout many “ice age” cycles -  learn about the ice ages  -  and no concentration above 300 ppm is seen in ice core records until the past 200 years.

Measurements of the forms (isotopes) of carbon in the modern atmosphere show a clear fingerprint of the addition of “old” carbon (depleted in natural radioactive  14 C) coming from the combustion of fossil fuels (as opposed to “newer” carbon coming from living systems). In addition, it is known that human activities (excluding land use changes) currently emit an estimated 10 billion tonnes of carbon each year, mostly by burning fossil fuels, which is more than enough to explain the observed increase in concentration. These and other lines of evidence point conclusively to the fact that the elevated CO 2  concentration in our atmosphere is the result of human activities. 

Fig b2. Measurements of atmospheric CO 2  since 1958 from the Mauna Loa Observatory in Hawaii (black) and from the South Pole (red) show a steady annual increase in atmospheric CO 2  concentration. The measurements are made at remote places like these because they are not greatly influenced by local processes, so therefore they are representative of the background atmosphere. The small up-and-down saw-tooth pattern reflects seasonal changes in the release and uptake of CO 2  by plants. Source: Scripps CO2 Program

Figure b3. CO 2  variations during the past 1,000 years, obtained from analysis of air trapped in an ice core extracted from Antarctica (red squares), show a sharp rise in atmospheric CO 2  starting in the late 19th century. Modern atmospheric measurements from Mauna Loa are superimposed in gray. Source: figure by Eric Wolff, data from Etheridge et al., 1996; MacFarling Meure et al., 2006; Scripps CO 2  Program. 

Climate records show a warming trend

Estimating global average surface air temperature increase requires careful analysis of millions of measurements from around the world, including from land stations, ships, and satellites. Despite the many complications of synthesising such data, multiple independent teams have concluded separately and unanimously that global average surface air temperature has risen by about 1 °C (1.8 °F) since 1900 [Figure B4]. Although the record shows several pauses and accelerations in the increasing trend, each of the last four decades has been warmer than any other decade in the instrumental record since 1850.

Going further back in time before accurate thermometers were widely available, temperatures can be reconstructed using climate-sensitive indicators “proxies” in materials such as tree rings, ice cores, and marine sediments. Comparisons of the thermometer record with these proxy measurements suggest that the time since the early 1980s has been the warmest 40-year period in at least eight centuries, and that global temperature is rising towards peak temperatures last seen 5,000 to 10,000 years ago in the warmest part of our current interglacial period.

Many other impacts associated with the warming trend have become evident in recent years. Arctic summer sea ice cover has shrunk dramatically. The heat content of the ocean has increased. Global average sea level has risen by approximately 16 cm (6 inches) since 1901, due both to the expansion of warmer ocean water and to the addition of melt waters from glaciers and ice sheets on land. Warming and precipitation changes are altering the geographical ranges of many plant and animal species and the timing of their life cycles. In addition to the effects on climate, some of the excess CO 2  in the atmosphere is being taken up by the ocean, changing its chemical composition (causing ocean acidification).

Figure b4. Earth’s global average surface temperature has risen, as shown in this plot of combined land and ocean measurements from 1850 to 2019 derived from three independent analyses of the available data sets. The top panel shows annual average values from the three analyses, and the bottom panel shows decadal average values, including the uncertainty range (grey bars) for the maroon (HadCRUT4) dataset. The temperature changes are relative to the global average surface temperature, averaged from 1961−1990. Source: Based on IPCC AR5, data from the HadCRUT4 dataset (black), NOAA Climate.gov; data from UK Met Office Hadley Centre (maroon), US National Aeronautics and Space Administration Goddard Institute for Space Studies (red), and US National Oceanic and Atmospheric Administration National Centers for Environmental Information (orange). 

Many complex processes shape our climate

Based just on the physics of the amount of energy that CO 2 absorbs and emits, a doubling of atmospheric CO 2 concentration from pre-industrial levels (up to about 560 ppm) would by itself cause a global average temperature increase of about 1 °C (1.8 °F). In the overall climate system, however, things are more complex; warming leads to further effects (feedbacks) that either amplify or diminish the initial warming.

The most important feedbacks involve various forms of water. A warmer atmosphere generally contains more water vapour. Water vapour is a potent greenhouse gas, thus causing more warming; its short lifetime in the atmosphere keeps its increase largely in step with warming. Thus, water vapour is treated as an amplifier, and not a driver, of climate change. Higher temperatures in the polar regions melt sea ice and reduce seasonal snow cover, exposing a darker ocean and land surface that can absorb more heat, causing further warming. Another important but uncertain feedback concerns changes in clouds. Warming and increases in water vapour together may cause cloud cover to increase or decrease which can either amplify or dampen temperature change depending on the changes in the horizontal extent, altitude, and properties of clouds. The latest assessment of the science indicates that the overall net global effect of cloud changes is likely to be to amplify warming.

The ocean moderates climate change. The ocean is a huge heat reservoir, but it is difficult to heat its full depth because warm water tends to stay near the surface. The rate at which heat is transferred to the deep ocean is therefore slow; it varies from year to year and from decade to decade, and it helps to determine the pace of warming at the surface. Observations of the sub-surface ocean are limited prior to about 1970, but since then, warming of the upper 700 m (2,300 feet) is readily apparent, and deeper warming is also clearly observed since about 1990.

Surface temperatures and rainfall in most regions vary greatly from the global average because of geographical location, in particular latitude and continental position. Both the average values of temperature, rainfall, and their extremes (which generally have the largest impacts on natural systems and human infrastructure), are also strongly affected by local patterns of winds.

Estimating the effects of feedback processes, the pace of the warming, and regional climate change requires the use of mathematical models of the atmosphere, ocean, land, and ice (the cryosphere) built upon established laws of physics and the latest understanding of the physical, chemical and biological processes affecting climate, and run on powerful computers. Models vary in their projections of how much additional warming to expect (depending on the type of model and on assumptions used in simulating certain climate processes, particularly cloud formation and ocean mixing), but all such models agree that the overall net effect of feedbacks is to amplify warming.

Human activities are changing the climate

Rigorous analysis of all data and lines of evidence shows that most of the observed global warming over the past 50 years or so cannot be explained by natural causes and instead requires a significant role for the influence of human activities.

In order to discern the human influence on climate, scientists must consider many natural variations that affect temperature, precipitation, and other aspects of climate from local to global scale, on timescales from days to decades and longer. One natural variation is the El Niño Southern Oscillation (ENSO), an irregular alternation between warming and cooling (lasting about two to seven years) in the equatorial Pacific Ocean that causes significant year-to-year regional and global shifts in temperature and rainfall patterns. Volcanic eruptions also alter climate, in part increasing the amount of small (aerosol) particles in the stratosphere that reflect or absorb sunlight, leading to a short-term surface cooling lasting typically about two to three years. Over hundreds of thousands of years, slow, recurring variations in Earth’s orbit around the Sun, which alter the distribution of solar energy received by Earth, have been enough to trigger the ice age cycles of the past 800,000 years.

Fingerprinting is a powerful way of studying the causes of climate change. Different influences on climate lead to different patterns seen in climate records. This becomes obvious when scientists probe beyond changes in the average temperature of the planet and look more closely at geographical and temporal patterns of climate change. For example, an increase in the Sun’s energy output will lead to a very different pattern of temperature change (across Earth’s surface and vertically in the atmosphere) compared to that induced by an increase in CO 2 concentration. Observed atmospheric temperature changes show a fingerprint much closer to that of a long-term CO 2 increase than to that of a fluctuating Sun alone. Scientists routinely test whether purely natural changes in the Sun, volcanic activity, or internal climate variability could plausibly explain the patterns of change they have observed in many different aspects of the climate system. These analyses have shown that the observed climate changes of the past several decades cannot be explained just by natural factors.

How will climate change in the future?

Scientists have made major advances in the observations, theory, and modelling of Earth’s climate system, and these advances have enabled them to project future climate change with increasing confidence. Nevertheless, several major issues make it impossible to give precise estimates of how global or regional temperature trends will evolve decade by decade into the future. Firstly, we cannot predict how much CO 2  human activities will emit, as this depends on factors such as how the global economy develops and how society’s production and consumption of energy changes in the coming decades. Secondly, with current understanding of the complexities of how climate feedbacks operate, there is a range of possible outcomes, even for a particular scenario of CO 2  emissions. Finally, over timescales of a decade or so, natural variability can modulate the effects of an underlying trend in temperature. Taken together, all model projections indicate that Earth will continue to warm considerably more over the next few decades to centuries. If there were no technological or policy changes to reduce emission trends from their current trajectory, then further globally-averaged warming of 2.6 to 4.8 °C (4.7 to 8.6 °F) in addition to that which has already occurred would be expected during the 21st century [Figure B5]. Projecting what those ranges will mean for the climate experienced at any particular location is a challenging scientific problem, but estimates are continuing to improve as regional and local-scale models advance.

Figure b5. The amount and rate of warming expected for the 21st century depends on the total amount of greenhouse gases that humankind emits. Models project the temperature increase for a business-as-usual emissions scenario (in red) and aggressive emission reductions, falling close to zero 50 years from now (in blue). Black is the modelled estimate of past warming. Each solid line represents the average of different model runs using the same emissions scenario, and the shaded areas provide a measure of the spread (one standard deviation) between the temperature changes projected by the different models. All data are relative to a reference period (set to zero) of 1986-2005. Source: Based on IPCC AR5

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What Are the Causes of Climate Change?

We can’t fight climate change without understanding what drives it.

Low water levels at Shasta Lake, California, following a historic drought in October 2021

Andrew Innerarity/California Department of Water Resources

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At the root of climate change is the phenomenon known as the greenhouse effect , the term scientists use to describe the way that certain atmospheric gases “trap” heat that would otherwise radiate upward, from the planet’s surface, into outer space. On the one hand, we have the greenhouse effect to thank for the presence of life on earth; without it, our planet would be cold and unlivable.

But beginning in the mid- to late-19th century, human activity began pushing the greenhouse effect to new levels. The result? A planet that’s warmer right now than at any other point in human history, and getting ever warmer. This global warming has, in turn, dramatically altered natural cycles and weather patterns, with impacts that include extreme heat, protracted drought, increased flooding, more intense storms, and rising sea levels. Taken together, these miserable and sometimes deadly effects are what have come to be known as climate change .

Detailing and discussing the human causes of climate change isn’t about shaming people, or trying to make them feel guilty for their choices. It’s about defining the problem so that we can arrive at effective solutions. And we must honestly address its origins—even though it can sometimes be difficult, or even uncomfortable, to do so. Human civilization has made extraordinary productivity leaps, some of which have led to our currently overheated planet. But by harnessing that same ability to innovate and attaching it to a renewed sense of shared responsibility, we can find ways to cool the planet down, fight climate change , and chart a course toward a more just, equitable, and sustainable future.

Here’s a rough breakdown of the factors that are driving climate change.

Natural causes of climate change

Human-driven causes of climate change, transportation, electricity generation, industry & manufacturing, agriculture, oil & gas development, deforestation, our lifestyle choices.

Some amount of climate change can be attributed to natural phenomena. Over the course of Earth’s existence, volcanic eruptions , fluctuations in solar radiation , tectonic shifts , and even small changes in our orbit have all had observable effects on planetary warming and cooling patterns.

But climate records are able to show that today’s global warming—particularly what has occured since the start of the industrial revolution—is happening much, much faster than ever before. According to NASA , “[t]hese natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.” And the records refute the misinformation that natural causes are the main culprits behind climate change, as some in the fossil fuel industry and conservative think tanks would like us to believe.

Chemical manufacturing plants emit fumes along Onondaga Lake in Solvay, New York, in the late-19th century. Over time, industrial development severely polluted the local area.

Library of Congress, Prints & Photographs Division, Detroit Publishing Company Collection

Scientists agree that human activity is the primary driver of what we’re seeing now worldwide. (This type of climate change is sometimes referred to as anthropogenic , which is just a way of saying “caused by human beings.”) The unchecked burning of fossil fuels over the past 150 years has drastically increased the presence of atmospheric greenhouse gases, most notably carbon dioxide . At the same time, logging and development have led to the widespread destruction of forests, wetlands, and other carbon sinks —natural resources that store carbon dioxide and prevent it from being released into the atmosphere.

Right now, atmospheric concentrations of greenhouse gases like carbon dioxide, methane , and nitrous oxide are the highest they’ve been in the last 800,000 years . Some greenhouse gases, like hydrochlorofluorocarbons (HFCs) , do not even exist in nature. By continuously pumping these gases into the air, we helped raise the earth’s average temperature by about 1.9 degrees Fahrenheit during the 20th century—which has brought us to our current era of deadly, and increasingly routine, weather extremes. And it’s important to note that while climate change affects everyone in some way, it doesn’t do so equally: All over the world, people of color and those living in economically disadvantaged or politically marginalized communities bear a much larger burden , despite the fact that these communities play a much smaller role in warming the planet.

Our ways of generating power for electricity, heat, and transportation, our built environment and industries, our ways of interacting with the land, and our consumption habits together serve as the primary drivers of climate change. While the percentages of greenhouse gases stemming from each source may fluctuate, the sources themselves remain relatively consistent.

Traffic on Interstate 25 in Denver

David Parsons/iStock

The cars, trucks, ships, and planes that we use to transport ourselves and our goods are a major source of global greenhouse gas emissions. (In the United States, they actually constitute the single-largest source.) Burning petroleum-based fuel in combustion engines releases massive amounts of carbon dioxide into the atmosphere. Passenger cars account for 41 percent of those emissions, with the typical passenger vehicle emitting about 4.6 metric tons of carbon dioxide per year. And trucks are by far the worst polluters on the road. They run almost constantly and largely burn diesel fuel, which is why, despite accounting for just 4 percent of U.S. vehicles, trucks emit 23 percent of all greenhouse gas emissions from transportation.

We can get these numbers down, but we need large-scale investments to get more zero-emission vehicles on the road and increase access to reliable public transit .

As of 2021, nearly 60 percent of the electricity used in the United States comes from the burning of coal, natural gas , and other fossil fuels . Because of the electricity sector’s historical investment in these dirty energy sources, it accounts for roughly a quarter of U.S. greenhouse gas emissions, including carbon dioxide, methane, and nitrous oxide.

That history is undergoing a major change, however: As renewable energy sources like wind and solar become cheaper and easier to develop, utilities are turning to them more frequently. The percentage of clean, renewable energy is growing every year—and with that growth comes a corresponding decrease in pollutants.

But while things are moving in the right direction, they’re not moving fast enough. If we’re to keep the earth’s average temperature from rising more than 1.5 degrees Celsius, which scientists say we must do in order to avoid the very worst impacts of climate change, we have to take every available opportunity to speed up the shift from fossil fuels to renewables in the electricity sector.

The factories and facilities that produce our goods are significant sources of greenhouse gases; in 2020, they were responsible for fully 24 percent of U.S. emissions. Most industrial emissions come from the production of a small set of carbon-intensive products, including basic chemicals, iron and steel, cement and concrete, aluminum, glass, and paper. To manufacture the building blocks of our infrastructure and the vast array of products demanded by consumers, producers must burn through massive amounts of energy. In addition, older facilities in need of efficiency upgrades frequently leak these gases, along with other harmful forms of air pollution .

One way to reduce the industrial sector’s carbon footprint is to increase efficiency through improved technology and stronger enforcement of pollution regulations. Another way is to rethink our attitudes toward consumption (particularly when it comes to plastics ), recycling , and reuse —so that we don’t need to be producing so many things in the first place. And, since major infrastructure projects rely heavily on industries like cement manufacturing (responsible for 7 percent of annual global greenhouse gas), policy mandates must leverage the government’s purchasing power to grow markets for cleaner alternatives, and ensure that state and federal agencies procure more sustainably produced materials for these projects. Hastening the switch from fossil fuels to renewables will also go a long way toward cleaning up this energy-intensive sector.

The advent of modern, industrialized agriculture has significantly altered the vital but delicate relationship between soil and the climate—so much so that agriculture accounted for 11 percent of U.S. greenhouse gas emissions in 2020. This sector is especially notorious for giving off large amounts of nitrous oxide and methane, powerful gases that are highly effective at trapping heat. The widespread adoption of chemical fertilizers , combined with certain crop-management practices that prioritize high yields over soil health, means that agriculture accounts for nearly three-quarters of the nitrous oxide found in our atmosphere. Meanwhile, large-scale industrialized livestock production continues to be a significant source of atmospheric methane, which is emitted as a function of the digestive processes of cattle and other ruminants.

Stephen McComber holds a squash harvested from the community garden in Kahnawà:ke Mohawk Territory, a First Nations reserve of the Mohawks of Kahnawà:ke, in Quebec.

Stephanie Foden for NRDC

But farmers and ranchers—especially Indigenous farmers, who have been tending the land according to sustainable principles —are reminding us that there’s more than one way to feed the world. By adopting the philosophies and methods associated with regenerative agriculture , we can slash emissions from this sector while boosting our soil’s capacity for sequestering carbon from the atmosphere, and producing healthier foods.

A decades-old, plugged and abandoned oil well at a cattle ranch in Crane County, Texas, in June 2021, when it was found to be leaking brine water

Matthew Busch/Bloomberg via Getty Images

Oil and gas lead to emissions at every stage of their production and consumption—not only when they’re burned as fuel, but just as soon as we drill a hole in the ground to begin extracting them. Fossil fuel development is a major source of methane, which invariably leaks from oil and gas operations : drilling, fracking , transporting, and refining. And while methane isn’t as prevalent a greenhouse gas as carbon dioxide, it’s many times more potent at trapping heat during the first 20 years of its release into the atmosphere. Even abandoned and inoperative wells—sometimes known as “orphaned” wells —leak methane. More than 3 million of these old, defunct wells are spread across the country and were responsible for emitting more than 280,000 metric tons of methane in 2018.

Unsurprisingly, given how much time we spend inside of them, our buildings—both residential and commercial—emit a lot of greenhouse gases. Heating, cooling, cooking, running appliances, and maintaining other building-wide systems accounted for 13 percent of U.S. emissions overall in 2020. And even worse, some 30 percent of the energy used in U.S. buildings goes to waste, on average.

Every day, great strides are being made in energy efficiency , allowing us to achieve the same (or even better) results with less energy expended. By requiring all new buildings to employ the highest efficiency standards—and by retrofitting existing buildings with the most up-to-date technologies—we’ll reduce emissions in this sector while simultaneously making it easier and cheaper for people in all communities to heat, cool, and power their homes: a top goal of the environmental justice movement.

An aerial view of clearcut sections of boreal forest near Dryden in Northwestern Ontario, Canada, in June 2019

River Jordan for NRDC

Another way we’re injecting more greenhouse gas into the atmosphere is through the clearcutting of the world’s forests and the degradation of its wetlands . Vegetation and soil store carbon by keeping it at ground level or underground. Through logging and other forms of development, we’re cutting down or digging up vegetative biomass and releasing all of its stored carbon into the air. In Canada’s boreal forest alone, clearcutting is responsible for releasing more than 25 million metric tons of carbon dioxide into the atmosphere each year—the emissions equivalent of 5.5 million vehicles.

Government policies that emphasize sustainable practices, combined with shifts in consumer behavior , are needed to offset this dynamic and restore the planet’s carbon sinks .

The Yellow Line Metro train crossing over the Potomac River from Washington, DC, to Virginia on June 24, 2022

Sarah Baker

The decisions we make every day as individuals—which products we purchase, how much electricity we consume, how we get around, what we eat (and what we don’t—food waste makes up 4 percent of total U.S. greenhouse gas emissions)—add up to our single, unique carbon footprints . Put all of them together and you end up with humanity’s collective carbon footprint. The first step in reducing it is for us to acknowledge the uneven distribution of climate change’s causes and effects, and for those who bear the greatest responsibility for global greenhouse gas emissions to slash them without bringing further harm to those who are least responsible .

The big, climate-affecting decisions made by utilities, industries, and governments are shaped, in the end, by us : our needs, our demands, our priorities. Winning the fight against climate change will require us to rethink those needs, ramp up those demands , and reset those priorities. Short-term thinking of the sort that enriches corporations must give way to long-term planning that strengthens communities and secures the health and safety of all people. And our definition of climate advocacy must go beyond slogans and move, swiftly, into the realm of collective action—fueled by righteous anger, perhaps, but guided by faith in science and in our ability to change the world for the better.

If our activity has brought us to this dangerous point in human history, breaking old patterns can help us find a way out.

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The Influence of Climate Change on Extreme Environmental Events

Climate change affects global temperature and precipitation patterns. These effects, in turn, influence the intensity and, in some cases, the frequency of extreme environmental events, such as forest fires, hurricanes, heat waves, floods, droughts, and storms.

Climatology, Earth Science, Ecology

Boise National Forest Fire

Research shows human-caused climate change has worsened the risk of extreme weather events like the wildfires of the western United States, such as this forest fire in the Boise National Forest, Idaho.

Photograph by David R. Frazier Photolibrary, Inc./Science Source

Climate change caused by the emission of greenhouse gases from human activities affects global temperature and precipitation . Records from the Intergovernmental Panel on Climate Change indicate that the global average temperature has increased by at least 0.4 degrees Celsius (0.72 degrees Fahrenheit) since the 1970s, and that by 2100, it could increase to around 4 degrees Celsius (7.2 degrees Fahrenheit) above preindustrial temperatures. While the global effects of climate change may seem too small to be noticed by people living around the world, we have already experienced the effects of climate change through severe weather events, including forest fires, hurricanes , droughts , heat waves, floods, and storms. Computer modelling of real data has shown that the frequency and intensity of these events are influenced by climate change. There is a distinction that needs to be made when it comes to the relationship between climate change and extreme environmental events: Climate change has not been proven to directly cause individual extreme environmental events, but it has been shown to make these events more destructive, and likely happen more frequently,than they normally would be. This drastic change is due to the increase in greenhouse gas emissions—primarily through the burning of fossil fuels for transportation, heat, and electricity—in the past 150 years. Greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, trap heat within Earth’s atmosphere, making the planet warmer. A warmer atmosphere affects the water cycle because warmer air can hold more water vapor . In fact, the air’s capacity to hold water vapor increases by 7 percent with an increase in temperature of 1 degree Celsius (1.8 degrees Fahrenheit). This, along with warmer ocean temperatures, leads to heavier precipitation. Heavy precipitation can cause problems like flooding and landslides —where large amounts of soil or rock slide down a slope. An increase in intense precipitation comes with an increase in intense dry periods as well. Essentially, climate change causes wet places to become wetter and dry places to become drier by altering large-scale atmospheric circulation patterns. Warmer temperatures on land lead to reduced snowpack , earlier snowmelt , and evaporation of water from freshwater bodies. Extreme heat can lead to more frequent, severe, and prolonged heat waves and droughts and can make forest fires worse. On top of that, wildfires are harder to put out when air temperature is high and soil moisture is low. The number of heat waves, heavy rain events, and major hurricanes has increased in the United States. Hurricane Katrina of 2005 and Hurricane Sandy of 2012 are two of the most costly hurricanes in the history of the United States. The number of hurricanes that have occurred over recent years has not been linked to climate change, but their intensity has. The wind speed of tropical storms is increased by warmer sea-surface temperatures; by the end of the century, scientists predict maximum wind speed will increase by 2–11 percent. Coastal cities that are vulnerable to hurricanes will also be impacted by the sea level rise of around 0.3–1.2 meters (0.98–3.94 feet) in the next century, which will worsen coastal storms and flooding. Without preparing for climate change–induced environmental hazards , an increasing number of people worldwide will lose their homes and be forced into poverty. An average of around 22.5 million people have been displaced per year by climate or weather-related events since 2008. One way to prepare for extreme environmental events is by using current and past data and records to create computer models that show the frequency and intensity of these events. These models can also be used to predict when and where future events will occur and how destructive they will be. With this information, we can prepare for extreme weather events by warning people living in high-risk areas and sending disaster relief . The impact of climate change can also be observed in models by simulating the effects of different concentrations of greenhouse gases on variables, such as wind, rainfall, temperature, and air pressure. Past models used to prove that there is a relationship between climate change and extreme environmental events were not always reliable. This was due to a lack of data as well as flaws in climate models at the time. However, climate models have become more reliable, and a new field of science has developed to determine how climate change directly impacts extreme weather events: extreme event attribution. Since 2004, scientists have published more than 170 studies on the role of human-induced climate change on 190 extreme weather events. Research has found that climate change has increased the risk of wildfires in the western United States, extreme rainfall in China, and drought in South Africa. Continuous research and improvement in the field of extreme event attribution may help us figure out more precisely how climate change impacts extreme weather events–and how we might change this course.

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Guest Essay

We Don’t See What Climate Change Is Doing to Us

By R. Jisung Park

Dr. Park is an environmental and labor economist and assistant professor at the University of Pennsylvania and the author of “Slow Burn: The Hidden Costs of a Warming World.”

Many of us realize climate change is a threat to our well-being. But what we have not yet grasped is that the devastation wreaked by climate change comes not just from headline-grabbing catastrophes but also from the subtler accumulation of innumerable slow and unequal burns that are already underway — the nearly invisible costs that may not raise the same alarm but that, in their pervasiveness and inequality, may be much more harmful than commonly realized. Recognizing these hidden costs will be essential as we prepare ourselves for the warming that we have ahead of us.

Responsibility for mitigating climate change on the local level lies in part with public institutions not only in encouraging emissions reductions but also in facilitating adaptation. Public discourse around climate change too often misses the central role that local institutions play in this latter function, how much of the realized pain locally depends on not simply the physical phenomena of climate change per se but also how they interact with human systems — economic, educational, legal and political.

Let’s start with heat, which is killing more people than most other natural disasters combined. Research shows that record-breaking heat waves are only part of the story. Instead, it may be the far more numerous unremarkably hot days that cause the bulk of societal destruction, including through their complex and often unnoticed effects on human health and productivity. In the United States, even moderately elevated temperatures — days in the 80s or 90s Fahrenheit — are responsible for just as many excess deaths as the record triple-digit heat waves, if not more, according to my calculations based on a recent analysis of Medicare records.

In some highly exposed and physically demanding industries, like mining, a day in the 90s can increase injury risk by over 65 percent relative to a day in the 60s. While some of these incidents involve clear cases of heat illness, my colleagues and I have found that a vast majority appear to come from ostensibly unrelated accidents, like construction workers falling off ladders and manufacturing workers mishandling hazardous machinery. In California, our research shows, heat might have routinely caused 20,000 workplace injuries per year, only a tiny fraction of which were officially recorded as heat-related.

A growing body of literature links temperature to cognitive performance and decision making. Research shows that hotter days lead to more mistakes, including among professional athletes ; more local crime ; and more violence in prisons , according to working papers. They also correspond with more use of profanity on social media , suggesting that even an incrementally hotter world is likely to be a nontrivially more irritable, error-prone and conflictual one.

Children are not immune. In research using over four million student test scores from New York City, I found that, from 1999 to 2011, students who took their high school Regents exams on a 90-degree day were 10 percent less likely to pass their subjects relative to a day in the 60s. In other research, my colleagues Joshua Goodman, Michael Hurwitz and Jonathan Smith and I found that across the country, hotter school years led to slower gains on standardized exams like the Preliminary SAT exams. It may not seem a huge effect, on average: roughly 1 percent of learning lost per one-degree-hotter school year temperatures. Probably hardly noticeable in any given year. But because these learning effects are cumulative, they may have significant consequences.

And that’s just heat. Researchers are bringing to light the more subtle yet cumulatively damaging effects of increased wildfires and other natural disasters. The hidden consequences of wildfire smoke may cut even deeper than the more visible death and destruction caused by the flames. Tallying the downstream economic and health costs of smoke exposure, researchers have estimated in a not-yet-published paper that increased wildfire smoke due to climate change may cause more than 20,000 additional deaths per year nationwide by 2050. Very few of these will be officially categorized as having been caused by wildfires, because they will have been the result of the cumulative influence of worsened air quality and weakened health over the course of many weeks and months. Research now suggests that wildfire smoke can adversely affect fetal health , student learning and workers’ earnings as well.

Since even noncatastrophic climate change may be more subtly damaging and inequality amplifying than we used to think, local interventions are essential to help us prepare for the warming that is to come.

At present, our social and economic systems are not well prepared to adjust to the accumulating damage wreaked by climate change, even though much of what determines whether climate change hurts us depends on the choices we make as individuals and as a society. Whether a hot day leads to mild discomfort or widespread mortality comes down to human decisions — individual decisions such as whether to install and operate air-conditioning and collective decisions around the pricing and availability of insurance, the allocation of hospital beds or the procedures and norms governing how and when people work.

Recent research indicates that how temperature affects human health depends greatly on the adaptations that happen to be at play locally. For instance, a day above 85 degrees in the coldest U.S. ZIP codes has nearly 10 times the effect on elderly mortality relative to in the warmest ZIP codes. In other words, a string of such days in a place like Seattle will lead to a much higher increase in the mortality rate than in a place like Houston, even though both places have similar income levels. In rural India , institutional factors like access to banking may affect how many lives are ultimately lost because of heat; heat can reduce crop yields, leaving subsistence farmers dependent on financing sources to keep them afloat.

In our research of heat and learning , we found that the adverse effects of a one-degree-hotter school year are two to three times as large for Black and Hispanic students, who are less likely to have working air-conditioning at school or at home even within a given city, and are virtually nonexistent in schools and neighborhoods with high levels of home and school air-conditioning. We estimate that hotter temperatures may already be responsible for 5 percent of racial academic achievement gaps. Without remedial investments, climate change is likely to widen these gaps. With a shift in focus to these subtler social costs, we can devise and carry out more effective strategies. But right now, adaptation efforts remain highly fragmented and are often focused on more visibly salient climate hazards, like storm surges .

And, of course, an empirically nuanced understanding of climate damages makes it even clearer that reducing emissions aggressively makes cost-benefit sense not only because we want to insure against total ecological breakdown (cue “extinction rebellion” and “tipping points”) but also because the economic costs of even noncatastrophic warming may be considerable. Recent Environmental Protection Agency estimates that incorporate just some of these cumulative impacts suggest that a single ton of carbon dioxide sets in motion $190 worth of future social costs, which means that technologies that can reduce such emissions at a lower per-ton cost are most likely worth pursuing.

Climate change is a complex phenomenon whose ultimate costs will depend not only on how quickly we transition away from fossil fuels but also on how well we adapt our social and economic systems to the warming we have in store. A proactive stance toward adaptation and resilience may be useful from the standpoint of safeguarding one’s own physical and financial security, whether as a homeowner or the head of a Fortune 500 company. It may be vital for ensuring that the ladders of economic opportunity are not deteriorating for those attempting to climb its lower rungs.

R. Jisung Park is an environmental and labor economist and assistant professor at the University of Pennsylvania and the author of “Slow Burn: The Hidden Costs of a Warming World.”

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Climate Change: Causes and Effects

Last updated on April 2, 2024 by ClearIAS Team

India ranks fifth globally in terms of climate change vulnerability. Due to climate change, India suffered losses of almost 37 billion dollars in 2018 (almost twice what it lost between 1998-2017).

According to MIT, 78 out of India’s 89 urban regions will experience a considerable increase in flash floods if preindustrial temperatures are increased by 2° Celsius.

Sea level rise and stronger cyclones have already been brought on by an increase in sea surface temperature.

Table of Contents

What Is Climate Change?

Climate change means a long-term shift in temperature and weather patterns that may be natural such as through variations in the solar cycle or a result of anthropogenic activities such as carbon emission.

• Since the 1800s, human activities, primarily the combustion of fossil fuels like coal, oil, and gas have been the primary cause of climate change.
• Fossil fuel combustion produces greenhouse gas emissions that serve as a blanket around the earth, trapping heat from the sun and increasing temperatures.
• Carbon dioxide and methane are two prominent greenhouse gas emissions that are contributing to climate change. These are produced, for instance, by burning coal or gasoline.
• Carbon dioxide can also be released during forest and land clearing and Methane is emitted primarily by waste landfills. Among all, the major emitters are energy, industry, transportation, buildings, agriculture, and land use.

Key Findings Related to Climate

• China is the largest emitter of carbon dioxide which comprises 30.60% of the CO2 emission worldwide. China is followed by the USA and India.
• The Earth is now about 1.1°C warmer than it was in the 1800s. The commitment made under the Paris Agreement may not be met.
• By the end of the century, the temperature might rise by as much as 4.4°C if carbon dioxide emissions continue on their current course.
• The levels of greenhouse gases rose to a new height in 2019. The amount of carbon dioxide was 148% of preindustrial levels.
• While sea ice, the Greenland ice sheet, and glaciers have decreased over the same period and permafrost temperatures have climbed, the Arctic has warmed at least twice as fast as the global average.
• Between 2020 and 2030, the world’s production of fossil fuels must drop by around 6% to maintain a 1.5°C trajectory.

Also read:  Planetary Boundaries

Causes of Climate Change

Several anthropogenic activities induce harm to the environment. A few important of them are-

Power Generation

• Burning fossil fuels to provide power and heat accounts for a sizable portion of world emissions. Burning coal, oil, or gas releases carbon dioxide and nitrous oxide, which are still used to produce the majority of power.
• Only a little over a quarter of the world’s electricity is generated by renewable energy sources including wind, solar, and other natural resources.

Manufacturing and Industrial goods

• The manufacturing/industrial sector is one of the leading global producers of greenhouse gas emissions.
• Emissions from manufacturing and industry are mostly the result of burning fossil fuels to create energy for the production of items like textiles, electronics, plastics, cement, iron, and steel.
• Gases are also released during mining and other industrial activities, as well as during construction.
• Some products are also manufactured from chemicals derived from fossil fuels i.e., plastic products.

Deforestation

• A per cent of the world’s greenhouse gas emissions is caused by deforestation, along with agriculture and other changes in land use.
• As per an estimation, nearly 12 million hectares of forests are burned annually. Cutting down forests to make way for farms, pastures, or for other purposes also increases emissions.
• Forests absorb carbon dioxide, hence cutting or destroying forests reduces nature’s capacity to absorb emissions.

Transportation

• Fossil fuels are typically used to power transportation machines. As a result, emissions of greenhouse gases, particularly carbon dioxide, are greatly influenced by the transportation sector.
• In addition, statistics suggest that over the next few years, energy use for transportation will rise significantly.

Food Production

• In addition to deforestation and clearing land for agriculture and grazing, digestion by cows and sheep, production and use of fertilizers and manure, and the use of energy to run farm machinery or fishing boats, typically with fossil fuels, all contribute to the production of food.

Powering Buildings

• Over half of all electricity used worldwide is consumed by residential and commercial structures.
• Energy-related carbon dioxide emissions from buildings have increased over the past few years as a result of rising energy demand for heating and cooling, rising air conditioner ownership, and increased electricity use for lighting, appliances, and connected devices.

Also read: State of Global Climate Report 2023

Effects of Climate Change

Climate change has devastating impacts on us and the environment. The major effects are-

Increase in Temperature

• The global surface temperature rises together with greenhouse gas concentrations. The most recent ten years, 2011 to 2020, have been the warmest on record.
• Higher temperatures worsen heat-related illnesses and make it more challenging to work outside. When the weather is hotter, wildfires start more easily and spread more quickly.

More Severe Storms

• In many areas, destructive storms have increased in intensity and frequency. More moisture evaporates as temperatures rise , aggravating extremely heavy rains and flooding and resulting in more severe storms.
• The warming ocean has an impact on both the intensity and frequency of tropical storms. Warm ocean surface waters are the primary source of cyclones, hurricanes, and typhoons.

Frequent Drought

• Water availability is changing due to climate change, becoming more scarce in many places. In already water-stressed areas, global warming makes water shortages worse.
• It also increases the danger of ecological and agricultural droughts, which can harm crops and make ecosystems more vulnerable.

Warming and Rising Ocean

• The ocean absorbs carbon dioxide, keeping it out of the atmosphere. However, additional carbon dioxide causes the water to become more acidic, endangering coral reefs and marine life.
• It is the property of water that it expands when becomes warmer, therefore as the ocean warms, its volume will rise. Sea levels increase as a result of ice sheet melting, endangering coastal and island communities.

Loss of Species

• Both animals on land and in the ocean are at risk from climate change. As the temperatures rise, these risks rise as well.
• The rate of extinction on the planet is 1,000 times higher now than it has ever been in recorded human history. Within the next few decades, one million species face extinction .
• Threats from climate change include invasive pests and illnesses, forest fires, and harsh weather.

Food Scarcity

• Global hunger and poor nutrition are on the rise for a variety of reasons, including climate change and an increase in extreme weather occurrences. Crops, animals, and fisheries might all be lost or become less effective.
• Marine resources that provide food for billions of people are in danger as a result of the ocean’s increasing acidity.
• Food sources from herding, hunting, and fishing have been hampered in several Arctic regions due to changes in the snow and ice cover.
• Heat stress can reduce available water and grazing areas, which can lower crop output and have an impact on cattle.

Health Hazards

• The single greatest hazard to human health is climate change. Air pollution, sickness, harsh weather, forced relocation, stress on mental health, increasing hunger and inadequate nutrition in areas where people cannot grow or get enough food are only a few of the health effects of climate change.
• 13 million individuals every year are killed by environmental conditions. Extreme weather events increase fatalities and make it challenging for healthcare systems to keep up with the growing number of diseases caused by changing weather patterns.

Read:  Climate Resilient Health Systems;   Climate Change and Health

Deepen Poverty and Displacement

• Climate change makes it easier for people to fall into and stay in poverty.
• Floods have the potential to devastate homes and livelihoods in urban slums. Outdoor jobs may be challenging to perform in the heat. Crops may be impacted by water scarcity.
• Weather-related disasters have uprooted an estimated 23.1 million people annually on average over the previous ten years (2010-2019), leaving millions more at risk of poverty.
• The majority of refugees are from countries that are least able and prepared to adjust to the effects of climate change.

Read:  Impact of climate change on Indian monsoon

Every increase in global warming matters

Numerous UN assessments were endorsed by hundreds of experts and government reviewers who concluded that keeping the increase in global temperature to 1.5°C will help us escape the worst climatic effects and maintain a habitable climate.

However, according to current national climate plans, the average global warming by the end of the century will reach about 3.2°C.

Across the world, emissions that contribute to climate change are produced, yet some countries produce significantly more than others. 3 per cent of global emissions are produced by the 100 countries with the lowest emissions.

68% of the contribution comes from the ten countries with the highest emissions. Everyone must act to combat climate change, but those who contribute most to the issue must be the countries with a larger obligation to do so first.

Read:  Black carbon emissions

Article Written By: Priti Raj

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Climate Change Essay

500+ words essay on climate change.

Climate change is a major global challenge today, and the world is becoming more vulnerable to this change. Climate change refers to the changes in Earth’s climate condition. It describes the changes in the atmosphere which have taken place over a period ranging from decades to millions of years. A recent report from the United Nations predicted that the average global temperature could increase by 6˚ Celsius at the end of the century. Climate change has an adverse effect on the environment and ecosystem. With the help of this essay, students will get to know the causes and effects of climate change and possible solutions. Also, they will be able to write essays on similar topics and can boost their writing skills.

What Causes Climate Change?

The Earth’s climate has always changed and evolved. Some of these changes have been due to natural causes such as volcanic eruptions, floods, forest fires etc., but quite a few of them are due to human activities. Human activities such as deforestation, burning fossil fuels, farming livestock etc., generate an enormous amount of greenhouse gases. This results in the greenhouse effect and global warming which are the major causes of climate change.

Effects of Climate Change

If the current situation of climate change continues in a similar manner, then it will impact all forms of life on the earth. The earth’s temperature will rise, the monsoon patterns will change, sea levels will rise, and storms, volcanic eruptions and natural disasters will occur frequently. The biological and ecological balance of the earth will get disturbed. The environment will get polluted and humans will not be able to get fresh air to breathe and fresh water to drink. Life on earth will come to an end.

Steps to be Taken to Reduce Climate Change

The Government of India has taken many measures to improve the dire situation of Climate Change. The Ministry of Environment and Forests is the nodal agency for climate change issues in India. It has initiated several climate-friendly measures, particularly in the area of renewable energy. India took several steps and policy initiatives to create awareness about climate change and help capacity building for adaptation measures. It has initiated a “Green India” programme under which various trees are planted to make the forest land more green and fertile.

We need to follow the path of sustainable development to effectively address the concerns of climate change. We need to minimise the use of fossil fuels, which is the major cause of global warming. We must adopt alternative sources of energy, such as hydropower, solar and wind energy to make a progressive transition to clean energy. Mahatma Gandhi said that “Earth provides enough to satisfy every man’s need, but not any man’s greed”. With this view, we must remodel our outlook and achieve the goal of sustainable development. By adopting clean technologies, equitable distribution of resources and addressing the issues of equity and justice, we can make our developmental process more harmonious with nature.

We hope students liked this essay on Climate Change and gathered useful information on this topic so that they can write essays in their own words. To get more study material related to the CBSE, ICSE, State Board and Competitive exams, keep visiting the BYJU’S website.

Frequently Asked Questions on climate change Essay

What are the reasons for climate change.

1. Deforestation 2. Excessive usage of fossil fuels 3. Water, Soil pollution 4. Plastic and other non-biodegradable waste 5. Wildlife and nature extinction

How can we save this climate change situation?

1. Avoid over usage of natural resources 2. Do not use or buy items made from animals 3. Avoid plastic usage and pollution

Are there any natural causes for climate change?

Yes, some of the natural causes for climate change are: 1. Solar variations 2. Volcanic eruption and tsunamis 3. Earth’s orbital changes

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Climate Matters • March 20, 2024

Warming Climate, More Pollen, Worse Allergies

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KEY CONCEPTS

Our warming climate results in more freeze-free days each year — giving plants more time to grow and release allergy-inducing pollen.

The freeze-free growing season lengthened in 83% (164) of 197 U.S. cities analyzed since 1970. 

These 164 cities saw their freeze-free season lengthen by 19 days on average. 

Climate change contributes to earlier, longer, worse allergy seasons for millions in the U.S. that suffer from seasonal allergies to pollen — including 19% of children.

Climate Central’s fact sheet, Climate Change & Children’s Health: Seasonal Allergies , details how the climate trends that are worsening allergy season affect children’s health and well-being.

Download data: Freeze-free growing season trends

Warming climate, longer pollen season, worse allergies

The first leaves and blooms of spring are arriving days to weeks early in large parts of the southern and central U.S., according to the USA National Phenology Network.

That’s bad news for people with seasonal allergies — about one-quarter of adults and one-in-five children in the U.S.

Earlier springs, longer pollen seasons, and worse seasonal allergies are all linked to our warming climate.

Climate Central’s report Seasonal Allergies: Pollen and Mold reviews weather and climate trends that affect pollen seasons and the related health risks. 

Carbon pollution (primarily from burning coal, oil, and natural gas) traps heat in the atmosphere and contributes to spring warming trends across the U.S. 

Warmer, earlier spring means a longer growing season — giving plants more time to grow and release allergy-inducing pollen earlier in spring and later into fall. 

Higher levels of CO2 in the air can also boost pollen production in plants, particularly in grasses and ragweed . With continued high rates of CO2 pollution, the U.S. could face up to a 200% increase in pollen production by the end of this century, according to a recent study.

As a result of CO2 buildup and warming, allergy season now arrives earlier in the spring and lasts later into the fall . A recent study found that human-caused warming was a primary driver of North American pollen seasons lengthening (by 20 days on average) from 1990 to 2018.

Longer growing season across the U.S.

Climate Central assessed temperature trends in 197 U.S. cities to see how freeze-free season length has changed from 1970 through 2023 (see Methodology). 

The freeze-free season lengthened in 83% (164) of the 197 cities analyzed since 1970. 

In 60 cities, the season between the last and first freeze grew by at least three weeks.

The freeze-free growing season increased the most in: Reno, Nev. (95 more days); Las Cruces, N.M. (65 more days); Medford, Ore. (61 more days); Boise, Idaho (51 more days); and Tupelo, Miss. (50 more days). 

All nine major U.S. climate regions have seen their freeze-free growing seasons lengthen by at least 11 days on average since 1970. 

Among regions, the freeze-free season lengthened by more than two weeks on average in: the Northwest (26 more days); the Southeast and Northeast (15 more days, respectively); and the Upper Midwest (14 more days). 

Effects of longer, worse pollen season on children

Longer and more intense pollen seasons can have serious consequences for people with respiratory illnesses like asthma — particularly for children. 

Around 19% of children in the U.S. suffer from seasonal allergies, with symptoms that include sneezing, coughing, itchy or watery eyes, and runny noses. 

Pollen is also a trigger for asthma, which affects 6.5% of children in the U.S. According to the Asthma and Allergy Foundation of America, allergic asthma is the most common type of asthma, and is most prevalent in early childhood.

Seasonal allergies and asthma can also affect children’s quality of life including school performance, mood, and sleep in adolescents aged 10-19 years.

Not only do children experience the current effects of climate change on allergies, but younger generations will experience more warming over their lifetimes if carbon pollution continues.

Continued warming could further worsen allergies for children, according to analysis from the U.S. EPA . The analysis found that 2°C (3.6°F) of warming could result in a 17% annual increase in asthma-related emergency room visits among children due to pollen exposure, relative to baseline conditions (1986-2005). Projected increases were largest in Indiana, Kentucky, Ohio, Vermont, and West Virginia. 

The same U.S. EPA analysis also found that oak pollen exposure disproportionately impacts Hispanic, Asian, and Black children, as well as low-income, limited English-speaking, and uninsured children. 

According to the Asthma and Allergy Foundation of America, Black and Puerto Rican children are between two and three times more likely to have asthma than white children, and therefore more at risk for allergic asthma. 

Protecting children’s health

Parents and caregivers can protect children’s health, now and in the future, by minimizing the harmful effects of seasonal allergies in a changing climate. A few key ways:

Respond to symptoms, not the season. Children with allergies may experience symptoms earlier or later than usual as growing seasons expand and shift. 

Minimize exposure. Check local air quality reports and allergen forecasts before heading outside. When pollen concentrations are high, consider limiting time outdoors for children with allergies or asthma.

Make the indoors safer and more comfortable. Close windows and doors to minimize aeroallergens inside. Use high-efficiency particulate air (HEPA) filters in living spaces and bedrooms to clean the air. 

Commit to rapid, sustained cuts to carbon pollution from burning fossil fuels. Because higher levels of CO2 increase pollen production, reducing carbon pollution will bring more and sooner benefits to allergy sufferers of all ages.

LOCAL STORY ANGLES

Find local pollen and mold counts..

There are pollen and mold spore monitoring stations across the U.S. Local allergen counts and forecasts can be found through resources such as the National Allergy Bureau . State or tribal agencies for environmental protection or public health may also have relevant air quality reports.

See where your city ranks.

The severity of the allergy season varies across the country. The Asthma and Allergy Foundation of America (AAFA) releases an annual report on the Allergy Capitals in the U.S., ranking cities based on pollen scores, over-the-counter medicine use, and the availability of board-certified allergists. Check out how your city ranked on AAFA’s Allergy Capitals list in 2023; the 2024 report will be released soon. The AAFA’s annual Asthma Capitals report also ranks U.S. cities where it’s most challenging to live with asthma. 

CONTACT EXPERTS

Lisa Patel, MD Clinical Associate Professor of Pediatrics and Pediatrician at Stanford Medicine Children’s Health Executive Director, Medical Society Consortium on Climate and Health Related expertise: children's health and climate change Media contact: [email protected]

Susan Anenberg, PhD Professor and Chair, Environmental and Occupational Health Department George Washington University Related expertise: climate change and health, air pollution Media contact: Kathleen Fackelmann ( [email protected] )

Lauren Gentile, PhD Geographer Environmental Protection Agency’s Climate Change Division Relevant expertise: seasonal changes Media contact: Shayla Powell ( [email protected] )

FIND EXPERTS

Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts. 

Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.  

Explore databases such as 500 Women Scientists , BIPOC Climate and Energy Justice PhDs , and Diverse Sources to find and amplify diverse expert voices. 

Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area. 

METHODOLOGY

Daily minimum temperature data from 1970-2023 were obtained from the Applied Climate Information System . The length of the annual freeze-free season was determined based on the annual count of consecutive days with minimum temperatures above 32°F, i.e., the time between the last day below 32°F (January through July) and the first day below 32°F (July through December). Years with freeze-free seasons of less than two weeks (e.g., beginning June 30, ending July 3) were dropped from the analysis. This condition affected several years in Bend, Ore. and Butte, Mont.

Of 247 total stations assessed, 44 had an average growing season length of less than three months or a year-round lack of sustained freeze and were therefore excluded from this analysis. Reported long-term (1970-2023) trends in freeze-free season length are based on linear regression. Summary statistics were reported for 197 of the 203 remaining stations due to data completeness issues for six stations: Bend, Ore.; Dothan, Ala.; Hazard, Ky.; Jefferson City, Mo; Twin Falls, Idaho; and Wheeling, W.Va.

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How light can vaporize water without the need for heat

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It’s the most fundamental of processes — the evaporation of water from the surfaces of oceans and lakes, the burning off of fog in the morning sun, and the drying of briny ponds that leaves solid salt behind. Evaporation is all around us, and humans have been observing it and making use of it for as long as we have existed.

And yet, it turns out, we’ve been missing a major part of the picture all along.

In a series of painstakingly precise experiments, a team of researchers at MIT has demonstrated that heat isn’t alone in causing water to evaporate. Light, striking the water’s surface where air and water meet, can break water molecules away and float them into the air, causing evaporation in the absence of any source of heat.

The astonishing new discovery could have a wide range of significant implications. It could help explain mysterious measurements over the years of how sunlight affects clouds, and therefore affect calculations of the effects of climate change on cloud cover and precipitation. It could also lead to new ways of designing industrial processes such as solar-powered desalination or drying of materials.

The findings, and the many different lines of evidence that demonstrate the reality of the phenomenon and the details of how it works, are described today in the journal PNAS, in a paper by Carl Richard Soderberg Professor of Power Engineering Gang Chen, postdocs Guangxin Lv and Yaodong Tu, and graduate student James Zhang.

The authors say their study suggests that the effect should happen widely in nature— everywhere from clouds to fogs to the surfaces of oceans, soils, and plants — and that it could also lead to new practical applications, including in energy and clean water production. “I think this has a lot of applications,” Chen says. “We’re exploring all these different directions. And of course, it also affects the basic science, like the effects of clouds on climate, because clouds are the most uncertain aspect of climate models.”

A newfound phenomenon

The new work builds on research reported last year , which described this new “photomolecular effect” but only under very specialized conditions: on the surface of specially prepared hydrogels soaked with water. In the new study, the researchers demonstrate that the hydrogel is not necessary for the process; it occurs at any water surface exposed to light, whether it’s a flat surface like a body of water or a curved surface like a droplet of cloud vapor.

Because the effect was so unexpected, the team worked to prove its existence with as many different lines of evidence as possible. In this study, they report 14 different kinds of tests and measurements they carried out to establish that water was indeed evaporating — that is, molecules of water were being knocked loose from the water’s surface and wafted into the air — due to the light alone, not by heat, which was long assumed to be the only mechanism involved.

One key indicator, which showed up consistently in four different kinds of experiments under different conditions, was that as the water began to evaporate from a test container under visible light, the air temperature measured above the water’s surface cooled down and then leveled off, showing that thermal energy was not the driving force behind the effect.

Other key indicators that showed up included the way the evaporation effect varied depending on the angle of the light, the exact color of the light, and its polarization. None of these varying characteristics should happen because at these wavelengths, water hardly absorbs light at all — and yet the researchers observed them.

The effect is strongest when light hits the water surface at an angle of 45 degrees. It is also strongest with a certain type of polarization, called transverse magnetic polarization. And it peaks in green light — which, oddly, is the color for which water is most transparent and thus interacts the least.

Chen and his co-researchers have proposed a physical mechanism that can explain the angle and polarization dependence of the effect, showing that the photons of light can impart a net force on water molecules at the water surface that is sufficient to knock them loose from the body of water. But they cannot yet account for the color dependence, which they say will require further study.

They have named this the photomolecular effect, by analogy with the photoelectric effect that was discovered by Heinrich Hertz in 1887 and finally explained by Albert Einstein in 1905. That effect was one of the first demonstrations that light also has particle characteristics, which had major implications in physics and led to a wide variety of applications, including LEDs. Just as the photoelectric effect liberates electrons from atoms in a material in response to being hit by a photon of light, the photomolecular effect shows that photons can liberate entire molecules from a liquid surface, the researchers say.

“The finding of evaporation caused by light instead of heat provides new disruptive knowledge of light-water interaction,” says Xiulin Ruan, professor of mechanical engineering at Purdue University, who was not involved in the study. “It could help us gain new understanding of how sunlight interacts with cloud, fog, oceans, and other natural water bodies to affect weather and climate. It has significant potential practical applications such as high-performance water desalination driven by solar energy. This research is among the rare group of truly revolutionary discoveries which are not widely accepted by the community right away but take time, sometimes a long time, to be confirmed.”

Solving a cloud conundrum

The finding may solve an 80-year-old mystery in climate science. Measurements of how clouds absorb sunlight have often shown that they are absorbing more sunlight than conventional physics dictates possible. The additional evaporation caused by this effect could account for the longstanding discrepancy, which has been a subject of dispute since such measurements are difficult to make.

“Those experiments are based on satellite data and flight data,“ Chen explains. “They fly an airplane on top of and below the clouds, and there are also data based on the ocean temperature and radiation balance. And they all conclude that there is more absorption by clouds than theory could calculate. However, due to the complexity of clouds and the difficulties of making such measurements, researchers have been debating whether such discrepancies are real or not. And what we discovered suggests that hey, there’s another mechanism for cloud absorption, which was not accounted for, and this mechanism might explain the discrepancies.”

Chen says he recently spoke about the phenomenon at an American Physical Society conference, and one physicist there who studies clouds and climate said they had never thought about this possibility, which could affect calculations of the complex effects of clouds on climate. The team conducted experiments using LEDs shining on an artificial cloud chamber, and they observed heating of the fog, which was not supposed to happen since water does not absorb in the visible spectrum. “Such heating can be explained based on the photomolecular effect more easily,” he says.

Lv says that of the many lines of evidence, “the flat region in the air-side temperature distribution above hot water will be the easiest for people to reproduce.” That temperature profile “is a signature” that demonstrates the effect clearly, he says.

Zhang adds: “It is quite hard to explain how this kind of flat temperature profile comes about without invoking some other mechanism” beyond the accepted theories of thermal evaporation. “It ties together what a whole lot of people are reporting in their solar desalination devices,” which again show evaporation rates that cannot be explained by the thermal input.

The effect can be substantial. Under the optimum conditions of color, angle, and polarization, Lv says, “the evaporation rate is four times the thermal limit.”

Already, since publication of the first paper, the team has been approached by companies that hope to harness the effect, Chen says, including for evaporating syrup and drying paper in a paper mill. The likeliest first applications will come in the areas of solar desalinization systems or other industrial drying processes, he says. “Drying consumes 20 percent of all industrial energy usage,” he points out.

Because the effect is so new and unexpected, Chen says, “This phenomenon should be very general, and our experiment is really just the beginning.” The experiments needed to demonstrate and quantify the effect are very time-consuming. “There are many variables, from understanding water itself, to extending to other materials, other liquids and even solids,” he says.

“The observations in the manuscript points to a new physical mechanism that foundationally alters our thinking on the kinetics of evaporation,” says Shannon Yee, an associate professor of mechanical engineering at Georgia Tech, who was not associated with this work. He adds, “Who would have thought that we are still learning about something as quotidian as water evaporating?”

“I think this work is very significant scientifically because it presents a new mechanism,” says University of Alberta Distinguished Professor Janet A.W. Elliott, who also was not associated with this work. “It may also turn out to be practically important for technology and our understanding of nature, because evaporation of water is ubiquitous and the effect appears to deliver significantly higher evaporation rates than the known thermal mechanism. …  My overall impression is this work is outstanding. It appears to be carefully done with many precise experiments lending support for one another.”

The work was partly supported by an MIT Bose Award. The authors are currently working on ways to make use of this effect for water desalination, in a project funded by the Abdul Latif Jameel Water and Food Systems Lab and the MIT-UMRP program.

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Press mentions, interesting engineering.

Interesting Engineering reporter Rizwan Choudhury spotlights a new study by MIT researchers that finds light can cause evaporation of water from a surface without the need for heat. The photomolecular effect “presents exciting practical possibilities,” writes Choudhury. “Solar desalination systems and industrial drying processes are prime candidates for harnessing this effect. Since drying consumes significant industrial energy, optimizing this process using light holds immense promise.”

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