Carbon sink

This article is about storage reservoirs for carbon. For the processes involved for storing carbon for a long time, see carbon sequestration.
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]

A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere".[2]: 2249  These sinks form an important part of the natural carbon cycle. An overarching term is carbon pool, which is all the places where carbon on Earth can be, i.e. the atmosphere, oceans, soil, florae, fossil fuel reservoirs and so forth. A carbon sink is a type of carbon pool that has the capability to take up more carbon from the atmosphere than it releases.

Globally, the two most important carbon sinks are vegetation and the ocean.[3] Soil is an important carbon storage medium. Much of the organic carbon retained in the soil of agricultural areas has been depleted due to intensive farming. Blue carbon designates carbon that is fixed via certain marine ecosystems. Coastal blue carbon includes mangroves, salt marshes and seagrasses. These make up a majority of ocean plant life and store large quantities of carbon. Deep blue carbon is located in international waters and includes carbon contained in "continental shelf waters, deep-sea waters and the sea floor beneath them".[4]

For climate change mitigation purposes, the maintenance and enhancement of natural carbon sinks, mainly soils and forests, is important.[5] [6] In the past, human practices like deforestation and industrial agriculture have depleted natural carbon sinks. This kind of land use change has been one of the causes of climate change.

  1. ^ "Global Carbon Budget 2021" (PDF). Global Carbon Project. 4 November 2021. p. 57. Archived (PDF) from the original on 11 December 2021. The cumulative contributions to the global carbon budget from 1850. The carbon imbalance represents the gap in our current understanding of sources & sinks. ... Source: Friedlingstein et al 2021; Global Carbon Project 2021
  2. ^ Cite error: The named reference IPCC AR6 WGI Glossary was invoked but never defined (see the help page).
  3. ^ "Carbon Sources and Sinks". National Geographic Society. 26 March 2020. Archived from the original on 14 December 2020. Retrieved 18 June 2021.
  4. ^ "The ocean – the world's greatest ally against climate change". United Nations. Retrieved 27 April 2023.
  5. ^ Binkley, Clark S.; Brand, David; Harkin, Zoe; Bull, Gary; Ravindranath, N. H.; Obersteiner, Michael; Nilsson, Sten; Yamagata, Yoshiki; Krott, Max (1 May 2002). "Carbon sink by the forest sector—options and needs for implementation". Forest Policy and Economics. 4 (1): 65–77. doi:10.1016/S1389-9341(02)00005-9. ISSN 1389-9341.
  6. ^ Batjes, N.H.; Ceschia, E.; Heuvelink, G.B.M.; Demenois, J.; le Maire, G.; Cardinael, R.; Arias-Navarro, C.; von Egmond, F. (October 2024). "Towards a modular, multi-ecosystem monitoring, reporting and verification (MRV) framework for soil organic carbon stock change assessment". Carbon Management. 15 (1): 2410812. doi:10.1080/17583004.2024.2410812.