Portal:Climate change

The Climate Change Portal

P:CCP:CC

Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. In a broader sense, climate change also includes previous long-term changes to Earth's climate. The modern-day rise in global temperatures is driven by human activities, especially fossil fuel (coal, oil and natural gas) burning since the Industrial Revolution. Fossil fuel use, deforestation, and some agricultural and industrial practices release greenhouse gases. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Earth's atmosphere now has roughly 50% more carbon dioxide, the main gas driving global warming, than it did at the end of the pre-industrial era, reaching levels not seen for millions of years.

Climate change has an increasingly large impact on the environment. Heat waves and wildfires are becoming more common. Amplified warming in the Arctic has contributed to thawing permafrost, retreat of glaciers and sea ice decline. Higher temperatures are also causing more intense storms, droughts, and other weather extremes. Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct. Even if efforts to minimize future warming are successful, some effects will continue for centuries. These include ocean heating, ocean acidification and sea level rise.

Climate change threatens people with increased flooding, extreme heat, increased food and water scarcity, more disease, and economic loss. Human migration and conflict can also be a result. The World Health Organization calls climate change one of the biggest threats to global health in the 21st century. Societies and ecosystems will experience more severe risks without action to limit warming. Adapting to climate change through efforts like flood control measures or drought-resistant crops partially reduces climate change risks, although some limits to adaptation have already been reached. Poorer communities are responsible for a small share of global emissions, yet have the least ability to adapt and are most vulnerable to climate change.

Many climate change impacts have been observed in the first decades of the 21st century, with 2024 the warmest on record at +1.60 °C (2.88 °F) since regular tracking began in 1850. Additional warming will increase these impacts and can trigger tipping points, such as melting all of the Greenland ice sheet. Under the 2015 Paris Agreement, nations collectively agreed to keep warming "well under 2 °C". However, with pledges made under the Agreement, global warming would still reach about 2.8 °C (5.0 °F) by the end of the century.

There is widespread support for climate action worldwide, and most countries aim to stop emitting carbon dioxide. Fossil fuels can be phased out by ending their subsidies, conserving energy and switching to energy sources that do not produce significant carbon pollution. These energy sources include wind, solar, hydro, and nuclear power. Cleanly generated electricity can replace fossil fuels for powering transportation, heating buildings, and running industrial processes. Carbon can also be removed from the atmosphere, for instance by increasing forest cover and farming with methods that store carbon in soil. (Full article...)

Read more about climate change

View new selections below (purge)

Selected article – show another

Effects of climate change are well documented and growing for Earth's natural environment and human societies. Changes to the climate system include an overall warming trend, changes to precipitation patterns, and more extreme weather. As the climate changes it impacts the natural environment with effects such as more intense forest fires, thawing permafrost, and desertification. These changes impact ecosystems and societies, and can become irreversible once tipping points are crossed. Climate activists are engaged in a range of activities around the world that seek to ameliorate these issues or prevent them from happening.

The effects of climate change vary in timing and location. Up until now the Arctic has warmed faster than most other regions due to climate change feedbacks. Surface air temperatures over land have also increased at about twice the rate they do over the ocean, causing intense heat waves. These temperatures would stabilize if greenhouse gas emissions were brought under control. Ice sheets and oceans absorb the vast majority of excess heat in the atmosphere, delaying effects there but causing them to accelerate and then continue after surface temperatures stabilize. Sea level rise is a particular long term concern as a result. The effects of ocean warming also include marine heatwaves, ocean stratification, deoxygenation, and changes to ocean currents. The ocean is also acidifying as it absorbs carbon dioxide from the atmosphere.

The ecosystems most immediately threatened by climate change are in the mountains, coral reefs, and the Arctic. Excess heat is causing environmental changes in those locations that exceed the ability of animals to adapt. Species are escaping heat by migrating towards the poles and to higher ground when they can. Sea level rise threatens coastal wetlands with flooding. Decreases in soil moisture in certain locations can cause desertification and damage ecosystems like the Amazon rainforest. At 2 °C (3.6 °F) of warming, around 10% of species on land would become critically endangered. (Full article...)

List of selected articles

edit

Selected picture – show another

Credit: Jami Dwyer

Jungle burned for agriculture in southern Mexico

More selected pictures

edit

WikiProjects


WikiProject Climate change	WikiProject Environment	WikiProject Globalization

Selected biography – show another

Sarah Kapnick is an American scientist, political advisor, and financier. She served as the fourth chief scientist of NOAA from April 2022 to October 2024, and is presently the inaugural Global Head of Climate Advisory at JP Morgan Chase. (Full article...)

List of selected biographies

General images

The following are images from various climate-related articles on Wikipedia.

Image 1The impact of the greenhouse effect on climate was presented to the public early in the 20th century, as succinctly described in this 1912 Popular Mechanics article. (from History of climate change science)
Image 2Global average temperatures show that the Medieval Warm Period was not a planet-wide phenomenon, and that the Little Ice Age was not a distinct planet-wide time period but rather the end of a long temperature decline that preceded recent global warming. (from Temperature record of the last 2,000 years)
Image 3Milutin Milanković (from History of climate change science)
Image 4Terms like "climate emergency" and climate crisis" have often been used by activists, and are increasingly found in academic papers. (from History of climate change science)
Image 5Human fingerprints for global warming (summary of observational evidence that human carbon dioxide emissions are causing the climate to warm). (from Causes of climate change)
Image 6Main sources of global methane emissions (2008–2017) according to the Global Carbon Project (from Causes of climate change)
Image 7A diagram which shows where the extra heat retained on Earth due to the energy imbalance is going.
Image 8CO₂ concentrations over the last 500 million years (from Carbon dioxide in the atmosphere of Earth)
Image 9Erratics, boulders deposited by glaciers far from any existing glaciers, led geologists to the conclusion that climate had changed in the past. (from History of climate change science)
Image 10The Fourth National Climate Assessment ("NCA4", USGCRP, 2017) includes charts illustrating that neither solar nor volcanic activity can explain the observed warming. (from Causes of climate change)
Image 11The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy. (from Causes of climate change)
Image 12Atmospheric CO₂ concentration measured at Mauna Loa Observatory in Hawaii from 1958 to 2023 (also called the Keeling Curve). The rise in CO₂ over that time period is clearly visible. The concentration is expressed as μmole per mole, or ppm. (from Carbon dioxide in the atmosphere of Earth)
Image 13Anthropogenic global warming—not global cooling or "imminent ice ages"—dominated peer-reviewed literature in the 1970s, contrary to false claims that climate science subsequently reversed its consensus. (from History of climate change science)
Image 14The Global Carbon Project shows how additions to CO₂ have been caused by different sources ramping up one after another. (from Causes of climate change)
Image 15Brown bars indicate drivers that increase global warming, and blue bars indicate those that decrease global warming. Future global warming potential for long lived drivers like carbon dioxide emissions is not represented. (from Causes of climate change)
Image 16Since the 1980s, global average surface temperatures during a given decade have almost always been higher than the average temperature in the preceding decade. (from History of climate change science)
Image 17Charles Keeling, receiving the National Medal of Science from George W. Bush, in 2001 (from History of climate change science)
Image 18Cumulative land-use change contributions to CO₂ emissions, by region. (from Causes of climate change)
Image 19Solar irradiance (yellow) plotted with temperature (red) since 1880. (from History of climate change science)
Image 20Increase in the Earth's non-cloud greenhouse effect (2000–2022) based on satellite data (from Earth's energy budget)
Image 21Greenhouse gases allow sunlight to pass through the atmosphere, heating the planet, but then absorb and redirect the infrared radiation (heat) the planet emits. (from Carbon dioxide in the atmosphere of Earth)
Image 22Sea ice reflects 50% to 70% of incoming sunlight, while the ocean, being darker, reflects only 6%. As an area of sea ice melts and exposes more ocean, more heat is absorbed by the ocean, raising temperatures that melt still more ice. This is a positive feedback process. (from Causes of climate change)
Image 23The growth in Earth's energy imbalance from satellite and in situ measurements (2005–2019). A rate of +1.0 W/m² summed over the planet's surface equates to a continuous heat uptake of about 500 terawatts (~0.3% of the incident solar radiation). (from Earth's energy budget)
Image 24Physical drivers of global warming that has happened so far. Future global warming potential for long lived drivers like carbon dioxide emissions is not represented. Whiskers on each bar show the possible error range. (from Carbon dioxide in the atmosphere of Earth)
Image 25Mean temperature anomalies during the period 1965 to 1975 with respect to the average temperatures from 1937 to 1946. This dataset was not available at the time. (from History of climate change science)
Image 26Schematic drawing of Earth's excess heat inventory and energy imbalance for two recent time periods (from Earth's energy budget)
Image 27Earth's energy imbalance has increased in the 21st century, reaching values twice that of prior estimates from the IPCC. The ability to observe this imbalance is deteriorating because satellites are being decommissioned. (from Earth's energy budget)
Image 28Between 1850 and 2019 the Global Carbon Project estimates that about 2/3rds of excess carbon dioxide emissions have been caused by burning fossil fuels, and a little less than half of that has stayed in the atmosphere. (from Carbon dioxide in the atmosphere of Earth)
Image 29The concentration of atmospheric carbon dioxide has been increasing in progressively greater amounts. (from Carbon dioxide in the atmosphere of Earth)
Image 30Eunice Newton Foote recognized carbon dioxide's heat-capturing effect in 1856, appreciating its implications for the planet. (from History of climate change science)
Image 31CO₂ sources and sinks since 1880. While there is little debate that excess carbon dioxide in the industrial era has mostly come from burning fossil fuels, the future strength of land and ocean carbon sinks is an area of study. (from Causes of climate change)
Image 32Warming influence of atmospheric greenhouse gases has nearly doubled since 1979, with carbon dioxide and methane being the dominant drivers. (from Causes of climate change)
Image 33Earth heating estimates from a combination of space altimetry and space gravimetry (from Earth's energy budget)
Image 34Concentration of atmospheric CO₂ over the last 40,000 years, from the Last Glacial Maximum to the present day. The current rate of increase is much higher than at any point during the last deglaciation. (from Carbon dioxide in the atmosphere of Earth)
Image 35Scientific consensus on causation: Academic studies of scientific agreement on human-caused global warming among climate experts (2010–2015) reflect that the level of consensus correlates with expertise in climate science.
A 2019 study found scientific consensus to be at 100%, and a 2021 study concluded that consensus exceeded 99%. Another 2021 study found that 98.7% of climate experts indicated that the Earth is getting warmer mostly because of human activity. (from History of climate change science)
Image 36Modeled simulation of the effect of various factors (including GHGs, Solar irradiance) singly and in combination, showing in particular that solar activity produces a small and nearly uniform warming, unlike what is observed. (from History of climate change science)
Image 37Energy flows between space, the atmosphere, and Earth's surface. Rising greenhouse gas levels are contributing to an energy imbalance. (from Causes of climate change)
Image 38The rising accumulation of energy in the oceanic, land, ice, and atmospheric components of Earth's climate system since 1960 (from Earth's energy budget)
Image 39Meat from cattle and sheep have the highest emissions intensity of any agricultural commodity. (from Causes of climate change)
Image 40Correspondence between temperature and atmospheric CO₂ during the last 800,000 years (from Carbon dioxide in the atmosphere of Earth)
Image 41The US, China and Russia have cumulatively contributed the greatest amounts of CO₂ since 1850. (from Carbon dioxide in the atmosphere of Earth)
Image 42CO₂ reduces the flux of thermal radiation emitted to space (causing the large dip near 667 cm⁻¹), thereby contributing to the greenhouse effect. (from Carbon dioxide in the atmosphere of Earth)
Image 43Joseph Fourier (from History of climate change science)
Image 44Carbon dioxide observations from 2008 to 2017 showing the seasonal variations and the difference between northern and southern hemispheres (from Carbon dioxide in the atmosphere of Earth)
Image 45Earth's energy budget (in W/m²) determines the climate. It is the balance of incoming and outgoing radiation and can be measured by satellites. The Earth's energy imbalance is the "net absorbed" energy amount. (from Earth's energy budget)
Image 46Longwave-infrared absorption coefficients of water vapor and carbon dioxide. For wavelengths near 15-microns, CO₂ is a much stronger absorber than water vapor. (from Carbon dioxide in the atmosphere of Earth)
Image 47Exterior of a Stevenson screen used for temperature measurements on land stations. (from History of climate change science)
Image 48Graphs of carbon dioxide concentration and temperature over time. (from Carbon dioxide in the atmosphere of Earth)
Image 49James Croll (from History of climate change science)
Image 50James Hansen during his 1988 testimony to Congress, which alerted the public to the dangers of global warming (from History of climate change science)

edit

Did you know – show another

... that global warming is cited as the main reason why southern England is becoming suitable for wine production and that it has similar soils and latitude to the Champagne region of France?

(Pictured left: A vineyard in Wyken, a suburb of Coventry, England)

Other "Did you know" facts...

Read more...

edit

Related portals

edit

Selected panorama – show another

Polar ice packs

Credit: NASA

This time series, based on satellite data, shows the annual Arctic sea ice minimum since 1979. The September 2010 extent was the third lowest in the satellite record.