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Soil carbon feedback

Map showing extent and types of permafrost in the Northern Hemisphere

The soil carbon feedback concerns the releases of carbon from soils in response to global warming. This response under climate change is a positive climate feedback. There is approximately two to three times more carbon in global soils than the Earth's atmosphere,[1][2] which makes understanding this feedback crucial to understand future climate change. An increased rate of soil respiration is the main cause of this feedback, where measurements imply that 4 °C of warming increases annual soil respiration by up to 37%.[3]

Soil Carbon Feedback to Climate ChangeEdit

An observation based study on future climate change, on the soil carbon feedback, conducted since 1991 in Harvard, suggests release of about 190 petagrams of soil carbon, the equivalent of the past two decades of greenhouse gas emissions from fossil fuel burning, until 2100 from the top 1-meter of Earth's soils, due to changes in microbial communities under elevated temperatures.[4][5]

A 2018 study concludes, "Climate-driven losses of soil carbon are currently occurring across many ecosystems, with a detectable and sustained trend emerging at the global scale."[2][6]

PermafrostEdit

Thawing of permafrost (frozen ground), which is located in higher latitudes, the Arctic and sub-Arctic regions, suggest based on observational evidence a linear and chronic release of greenhouse gas emissions with ongoing climate change from these carbon dynamics.[7]

Tipping PointEdit

A study published in 2011 identified a so-called compost-bomb instability, related to a tipping point with explosive soil carbon releases from peatlands. The authors noted that there is a unique stable soil carbon equilibrium for any fixed atmospheric temperature.[8]

UncertaintiesEdit

Climate models do not account for effects of biochemical heat release associated with microbial decomposition.[8]


See alsoEdit

ReferencesEdit

  1. ^ "Study: Soils Could Release Much More Carbon Than Expected as Climate Warms". Berkeley Lab. March 9, 2017.
  2. ^ a b Bond-Lamberty; et al. (2018). "Globally rising soil heterotrophic respiration over recent decades". Nature. 560 (7716): 80–83. doi:10.1038/s41586-018-0358-x. PMID 30068952.
  3. ^ Caitlin E. Hicks Pries, C. Castanha, R. C. Porras, M. S. Torn (2017). "The whole-soil carbon flux in response to warming". Science. AAAS. 355 (6332): 1420–1423. doi:10.1126/science.aal1319. PMID 28280251.CS1 maint: multiple names: authors list (link)
  4. ^ "One of the oldest climate change experiments has led to a troubling conclusion". The Washington Post. October 5, 2017.
  5. ^ Melillo; et al. (2017). "Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world". Science. AAAS. 358 (6359): 101–105. doi:10.1126/science.aan2874.
  6. ^ "In vicious cycle, warmer soil results in carbon to be released into the atmosphere from the soil, making climate change worse, study says". AP. 2018.
  7. ^ Schuur; et al. (2014). "Climate change and the permafrost carbon feedback". Nature. 520 (7546): 171–179. doi:10.1038/nature14338.
  8. ^ a b S. Wieczorek, P. Ashwin, C. M. Luke, P. M. Cox (2011). "Excitability in ramped systems: the compost-bomb instability". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. The Royal Society. 467 (2129): 1243–1269. doi:10.1098/rspa.2010.0485.CS1 maint: multiple names: authors list (link)

External linksEdit