Various aspects of climate change mitigation: Renewable energy (solar and wind power) in England, electrified public transport in France, a reforestation project in Haiti to remove carbon dioxide from the atmosphere, and an example of a plant-based meal

Climate change mitigation (or decarbonisation) is action to limit the greenhouse gases in the atmosphere that cause climate change. Climate change mitigation actions include conserving energy and replacing fossil fuels with clean energy sources. Secondary mitigation strategies include changes to land use and removing carbon dioxide (CO₂) from the atmosphere. Costs of climate change mitigation are estimated at around 1% and 2% of GDP.^[1][2] Current climate change mitigation policies are insufficient as they would still result in global warming of about 2.7 °C by 2100,^[3] significantly above the 2015 Paris Agreement's^[4] goal of limiting global warming to below 2 °C.^[5][6]

Solar energy and wind power can replace fossil fuels at the lowest cost compared to other renewable energy options.^[7] The availability of sunshine and wind is variable and can require electrical grid upgrades, such as using long-distance electricity transmission to group a range of power sources.^[8] Energy storage can also be used to even out power output, and demand management can limit power use when power generation is low. Cleanly generated electricity can usually replace fossil fuels for powering transportation, heating buildings, and running industrial processes.^{[citation needed]} Certain processes are more difficult to decarbonise, such as air travel and cement production. Carbon capture and storage (CCS) can be an option to reduce net emissions in these circumstances, although fossil fuel power plants with CCS technology is currently a high cost climate change mitigation strategy.^[9]

Human land use changes such as agriculture and deforestation cause about 1/4th of climate change. These changes impact how much CO₂ is absorbed by plant matter and how much organic matter decays or burns to release CO₂. These changes are part of the fast carbon cycle, whereas fossil fuels release CO₂ that was buried underground as part of the slow carbon cycle. Methane is a short lived greenhouse gas that is produced by decaying organic matter and livestock, as well as fossil fuel extraction. Land use changes can also impact precipitation patterns and the reflectivity of the surface of the Earth. It is possible to cut emissions from agriculture by reducing food waste, switching to a more plant-based diet (also referred to as low-carbon diet), and by improving farming processes.^[10]

Various policies can encourage climate change mitigation. Carbon pricing systems have been set up that either tax CO₂ emissions or cap total emissions and trade emission credits. Fossil fuel subsidies can be eliminated in favor of clean energy subsidies, and incentives offered for installing energy efficiency measures or switching to electric power sources.^[11] Another issue is overcoming environmental objections when constructing new clean energy sources and making grid modifications.

Definitions and scope