Editing IPCC:AR6/WGII/Chapter-2 (section)

===== 2.4.4.4.1 Observed terrestrial ecosystem carbon globally =====

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Terrestrial ecosystems contain carbon stocks: 450 GtC (range 380–540 GtC) in vegetation, 1700 ± 250 GtC in soils that are not permanently frozen and 1400 ± 200 GtC in permafrost ( [[#Hugelius--2014|Hugelius et al., 2014]] ; [[#Batjes--2016|Batjes, 2016]] ; [[#Jackson--2017|Jackson et al., 2017]] ; [[#Strauss--2017|Strauss et al., 2017]] ; [[#Erb--2018a|Erb et al., 2018a]] ; [[#Xu--2021a|Xu et al., 2021a]] ). Ecosystem carbon stocks, totalling 3000–4000 GtC (from the lowest and highest estimates above), substantially exceed the ~900 GtC carbon in unextracted fossil fuels (see( [[#Canadell--2021|Canadell et al., 2021]] )).

Deforestation, draining of peatlands and the expansion of agricultural fields, livestock pastures and human settlements and other LULCCs emitted carbon at a rate of 1.6 ± 0.7 Gt yr -1 from 2010 to 2019, ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ), of which wildfires and peat burning emitted 0.4 ± 0.2 Gt yr -1 from 1997 to 2016 ( [[#van%20der%20Werf--2017|van der Werf et al., 2017]] ). Anthropogenic climate change has caused some of these emissions through increases in wildfire ( [[#2.4.4.2.1|Section 2.4.4.2.1]] ) and tree mortality ( [[#2.4.4.3.1|Section 2.4.4.3.1]] ), but the fraction of the total remains unquantified. LUC produced ~15% of global anthropogenic emissions, from fossil fuels and land ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ). Terrestrial ecosystems removed carbon from the atmosphere through plant growth at a rate of -3.4 ± 0.9 Gt yr -1 from 2010 to 2019 ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ).

Tropical deforestation and the draining and burning of peatlands produce almost all of the carbon emissions from LUC ( [[#Houghton--2017|Houghton and Nassikas, 2017]] ; [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ), while forest growth accounts for two-thirds of ecosystem carbon removals from the atmosphere ( [[#Pugh--2019b|Pugh et al., 2019b]] ). Global terrestrial ecosystems comprised a net sink of -1.9 ± 1.1 Gt yr -1 from 2010 to 2019 ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ), mainly due to growth in forests ( [[#Harris--2021|Harris et al., 2021]] ; [[#Xu--2021a|Xu et al., 2021a]] ), mitigating ~31% of global emissions from the burning of fossil fuels and LUC ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ).

In summary, terrestrial ecosystems contain 3000–4000 GtC in vegetation, permafrost and soils, three to five times the amount of carbon in unextracted fossil fuels and 4.4 times the carbon currently in the atmosphere ( ''robust evidence'' , ''high agreement'' ). Tropical deforestation, the draining and burning of peatlands and other LULCCs emit 0.9–2.3 GtC yr -1 , ~15% of the global emissions from fossil fuels and ecosystems ( ''robust evidence'' , ''high agreement'' ). Terrestrial ecosystems currently remove more carbon from the atmosphere (-3.4±0.9 Gt yr -1 ) than they emit (+1.6±0.7 Gt yr -1 ), a net sink of -1.9±1.1 Gt yr -1 ( [[#Friedlingstein--2020|Friedlingstein et al., 2020]] ) . Thus, tropical rainforests, Arctic permafrost and other ecosystems provide the global ecosystem service of naturally preventing carbon from contributing to climate change ( ''high confidence'' ).

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