Climate change From Wikipedia, the free encyclopedia

Climate change
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"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.

Average surface air temperatures from 2011 to 2021 compared to the 1956–1976 average

Change in average surface air temperature since the industrial revolution, plus drivers for that change. Human activity has caused increased temperatures, with natural forces adding some variability.^[1]
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its impacts 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.^[2][3] Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases like carbon dioxide and methane.^[4] Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Adding to these gases traps more heat near the Earth's surface, causing global warming.
Due to climate change, deserts are expanding, while heat waves and wildfires are becoming more common.^[5] Increased warming in the Arctic has contributed to melting permafrost, glacial retreat and sea ice loss.^[6] Higher temperatures are also causing more intense storms, droughts, and other weather extremes.^[7] Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct.^[8] Climate change threatens people with food and water scarcity, increased flooding, extreme heat, more disease, and economic loss. Human migration and conflict can also be a result.^[9] The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century.^[10] Even if efforts to minimise future warming are successful, some effects will continue for centuries. These include sea level rise, and warmer, more acidic oceans.^[11]
Many of these impacts are already felt at the current 1.2 °C (2.2 °F) level of warming. Additional warming will increase these impacts and may trigger tipping points, such as the melting of the Greenland ice sheet.^[12] 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.^[13] Limiting warming to 1.5 °C will require halving emissions by 2030 and achieving net-zero emissions by 2050.^[14]



Some effects of climate change, clockwise from top left: Wildfire intensified by heat and drought, worsening droughts compromising water supplies, and bleaching of coral caused by ocean acidification and heating.
Making deep cuts in emissions will require switching away from burning fossil fuels and towards using electricity generated from low-carbon sources. This includes phasing out coal-fired power plants, vastly increasing use of wind, solar, and other types of renewable energy, and taking measures to reduce energy use. Electricity generated from non-carbon-emitting sources will need to replace fossil fuels for powering transportation, heating buildings, and operating industrial facilities.^[16][17] Carbon can also be removed from the atmosphere, for instance by increasing forest cover and by farming with methods that capture carbon in soil.^[18] While communities may adapt to climate change through efforts like better coastline protection, they cannot avert the risk of severe, widespread, and permanent impacts.^[19]
Contents

• 
  1 Terminology
  
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  2 Observed temperature rise
  
  • 
    2.1 Regional aspects to temperature rises
    
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  3 Drivers of recent temperature rise
  
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    3.1 Greenhouse gases
    
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    3.2 Aerosols and clouds
    
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    3.3 Land surface changes
    
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    3.4 Solar and volcanic activity
    
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    3.5 Climate change feedback
    
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  4 Future warming and the carbon budget
  
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  5 Impacts
  
  • 
    5.1 Environmental effects
    
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    5.2 Tipping points and long-term impacts
    
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    5.3 Nature and wildlife
    
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    5.4 Humans
    
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  6 Reducing and recapturing emissions
  
  • 
    6.1 Clean energy
    
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    6.2 Energy conservation
    
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    6.3 Agriculture and industry
    
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    6.4 Carbon sequestration
    
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  7 Adapting to a changing climate
  
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  8 Policies and politics
  
  • 
    8.1 Policy options
    
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    8.2 International climate agreements
    
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    8.3 National responses
    
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  9 Society
  
  • 
    9.1 Denial and misinformation
    
  • 
    9.2 Public awareness and opinion
    
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  10 History
  
  • 
    10.1 Early discoveries
    
  • 
    10.2 Development of a scientific consensus
    
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  11 See also
  
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  12 References
  
  • 
    12.1 Sources
    
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  13 External links