Global warming" redirects here. For other uses, see Climate change (disambiguation) and Global warming (disambiguation). This article is about contemporary climate change. For historical climate trends, see Climate variability and change.
The global map shows sea temperature rises of 0.5 to 1 degree Celsius; land temperature rises of 1 to 2 degree Celsius; and Arctic temperature rises of up to 4 degrees Celsius.
Surface air temperature change over the past 50 years[1]
Earth's average surface air temperature has increased almost 1.5 °C (about 2.5 °F) since the Industrial Revolution. Natural forces cause some variability, but the 20-year average shows the progressive influence of human activity.[2]
In common usage, climate change describes global warming the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels.[3][4] Fossil fuel use, deforestation, and some agricultural and industrial practices add to greenhouse gases, notably carbon dioxide and methane.[5] Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming.
Climate change has an increasing impact on the environment. Deserts are expanding, while heat waves and wildfires are becoming more common.[6] Amplified warming in the Arctic has contributed to thawing permafrost, retreat of glaciers and sea ice decline.[7] Higher temperatures are also causing more intense storms, droughts, and other weather extremes.[8] Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct.[9] Even if efforts to minimise future warming are successful, some effects will continue for centuries. These include ocean heating, ocean acidification and sea level rise.[10]
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.[11] The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century.[12] Societies and ecosystems will experience more severe risks without action to limit warming.[13] 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.[14] 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.[15][16]
Bobcat Fire in Monrovia, CA, September 10, 2020
Bleached colony of Acropora coral
A dry lakebed in California, which is experiencing its worst megadrought in 1,200 years.[17]
Some effects of climate change: Wildfire intensified by heat and drought, bleaching of coral caused by marine heatwaves, and worsening droughts compromising water supplies.
Many climate change impacts have been felt in recent years, with 2023 the warmest on record at +1.48 °C (2.66 °F).[18] Additional warming will increase these impacts and can trigger tipping points, such as melting all of the Greenland ice sheet.[19] 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 2.7 °C (4.9 °F) by the end of the century.[20] Limiting warming to 1.5 °C will require halving emissions by 2030 and achieving net-zero emissions by 2050.[21]
Strategies to phase out fossil fuels involve conserving energy, generating electricity cleanly, and using electricity to power transportation, heat buildings, and operate industrial facilities. The electricity supply can be made cleaner and more plentiful by vastly increasing deployment of wind, and solar power, alongside other forms of renewable energy and nuclear power.[22][23] Carbon can also be removed from the atmosphere, for instance by increasing forest cover and farming with methods that capture carbon in soil.[24]
