Carbon sink

[4] For climate change mitigation purposes, the maintenance and enhancement of natural carbon sinks, mainly soils and forests, is important.

[2]: 2244 The amount of carbon dioxide varies naturally in a dynamic equilibrium with photosynthesis of land plants.

[13] Public awareness of the significance of CO2 sinks has grown since passage of the 1997 Kyoto Protocol, which promotes their use as a form of carbon offset.

More recalcitrant organic carbon polymers such as cellulose, hemi-cellulose, lignin, aliphatic compounds, waxes and terpenoids are collectively retained as humus.

[18] Organic matter tends to accumulate in litter and soils of colder regions such as the boreal forests of North America and the Taiga of Russia.

Leaf litter and humus are rapidly oxidized and poorly retained in sub-tropical and tropical climate conditions due to high temperatures and extensive leaching by rainfall.

Areas, where shifting cultivation or slash and burn agriculture are practiced, are generally only fertile for two to three years before they are abandoned.

This can vary based on rainfall, the length of the winter season, and the frequency of naturally occurring lightning-induced grass-fires.

[20] Much organic carbon retained in many agricultural areas worldwide has been severely depleted due to intensive farming practices.

[24] Sustainable forest management, afforestation, reforestation are therefore important contributions to climate change mitigation.

[34] Therefore, scientists consider "the protection and recovery of carbon-rich and long-lived ecosystems, especially natural forests" to be "the major climate solution".

[40]: 2220  Most commonly, it refers to the role that tidal marshes, mangroves and seagrass meadows can play in carbon sequestration.

[46] This refers to the management of Earth's natural carbon sinks in a way that preserves or increases their capability to remove CO2 from the atmosphere and to store it durably.

[50]: 266  Scenarios that limit global warming to 1.5 °C typically project the large-scale use of carbon dioxide removal methods over the 21st century.

[46]: 43 To enhance carbon sequestration processes in oceans the following technologies have been proposed but none have achieved large scale application so far: Seaweed farming, ocean fertilisation, artificial upwelling, basalt storage, mineralization and deep sea sediments, adding bases to neutralize acids.

For this to happen, the harvested forests would need to be sustainably managed and wood from demolished timber buildings would need to be reused or preserved on land in various forms.

Carbon sinks (green bars on the right) remove carbon from the atmosphere, whereas carbon sources ( greenhouse gas emissions ) (grey bars on the left) add them. Since the 1850s, there are more carbon sources than sinks and therefore the carbon dioxide in Earth's atmosphere is rising. [ 1 ]
This diagram of the fast carbon cycle shows the movement of carbon between land, atmosphere, soil and oceans in billions of tons of carbon per year. Yellow numbers are natural fluxes, red are human contributions in billions of tons of carbon per year. White numbers indicate stored carbon.
Proportion of carbon stock in forest carbon pools, 2020 [ 22 ]
Ways one blue carbon habitat can influence the carbon concentration and future carbon sequestration in an adjacent blue carbon habitat [ 39 ]
About 58% of CO 2 emissions have been absorbed by carbon sinks , including plant growth, soil uptake, and ocean uptake ( 2020 Global Carbon Budget ).
Mjøstårnet , one of the tallest timber buildings, at its opening 2019