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. Greenhouse gas emissions are primarily caused by people burning fossil fuels such as coal, oil, and natural gas. Phasing out fossil fuel use can happen by conserving energy and replacing fossil fuels with clean energy sources such as wind, hydro, solar, and nuclear power. Secondary mitigation strategies include changes to land use and removing carbon dioxide (CO₂) from the atmosphere. Governments have pledged to reduce greenhouse gas emissions, but actions to date are insufficient to avoid dangerous levels of climate change.^[1]

Solar energy and wind power have the greatest potential for supplanting fossil fuels at the lowest cost compared to other options.^[2] 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.^[3] 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. 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 have not yet proven economical.^[4]

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.^[5]

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.^[6] Another issue is overcoming environmental objections when constructing new clean energy sources and making grid modifications. Current policies are insufficient as they would still result in global warming of about 2.7 °C by 2100.^[7] This warming is significantly above the 2015 Paris Agreement's goal of limiting global warming to well below 2 °C and preferably to 1.5 °C.^[8][9]

Definitions and scope

Climate change mitigation aims to sustain ecosystems to maintain human civilisation. This requires drastic cuts in greenhouse gas emissions .^{[10]: 1–64} The Intergovernmental Panel on Climate Change (IPCC) defines mitigation (of climate change) as "a human intervention to reduce emissions or enhance the sinks of greenhouse gases".^[11]: 2239

It is possible to approach various mitigation measures in parallel. This is because there is no single pathway to limit global warming to 1.5 or 2 °C.^[12]: 109 There are four types of measures:

1. Sustainable energy and sustainable transport
2. Energy conservation, including efficient energy use
3. Sustainable agriculture and green industrial policy
4. Enhancing carbon sinks and carbon dioxide removal (CDR), including carbon sequestration

The IPCC defined carbon dioxide removal as "Anthropogenic activities removing carbon dioxide (CO₂) from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential anthropogenic enhancement of biological or geochemical CO₂ sinks and direct air carbon dioxide capture and storage (DACCS), but excludes natural CO₂ uptake not directly caused by human activities."^[11]

Relationship with solar radiation modification (SRM)

While solar radiation modification (SRM) could reduce surface temperatures, it temporarily masks climate change rather than addressing the root cause, which is greenhouse gases.^{[13]: 14–56} SRM would work by altering how much solar radiation the Earth absorbs.^{[13]: 14–56} Examples include reducing the amount of sunlight reaching the surface, reducing the optical thickness and lifetime of clouds, and changing the ability of the surface to reflect radiation.^[14] The IPCC describes SRM as a climate risk reduction strategy or supplementary option rather than a climate mitigation option.^[13] Zdroj:https://en.wikipedia.org?pojem=Combating_climate_change
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