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

==== 2.3.1.1 The total net flux of CO2 between land and atmosphere ====

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The net effects of all anthropogenic and non-anthropogenic processes on managed and unmanaged land result in a net removal of CO <sub>2</sub> from the atmosphere ( ''high confidence'' ). This total net land-atmosphere removal (defined here as ''the total net land flux'' ) is estimated to have averaged 6.0 ± 2.0 GtCO <sub>2</sub> yr <sup>–1</sup> ( ''likely range'' ) from 2007–2016 (Table 2.3). The estimate is determined from summing the AFOLU and non-AFOLU fluxes due to transient climate change, CO <sub>2</sub> fertilisation and nitrogen deposition calculated by models in the global carbon budget (Le Quéré et al. 2018 <sup>[[#fn:r498|498]]</sup> ), and is consistent with inverse modelling techniques based on atmospheric CO <sub>2</sub> concentrations and air transport (range: 5.1–8.8 GtCO <sub>2</sub> yr <sup>–1</sup> ) (Peylin et al. 2013 <sup>[[#fn:r499|499]]</sup> ; Van Der Laan-Luijkx et al. 2017 <sup>[[#fn:r500|500]]</sup> ; Saeki and Patra 2017 <sup>[[#fn:r501|501]]</sup> ; Le Quéré et al. 2018 <sup>[[#fn:r502|502]]</sup> ) (see Box 2.2 for methods). A recent inverse analysis, considering carbon transport in rivers and oceans, found a net flux of CO <sub>2</sub> for land within this range, but a lower source from southern lands and a lower sink in northern lands (Resplandy et al. 2018 <sup>[[#fn:r503|503]]</sup> ).

The net removal of CO <sub>2</sub> by land has generally increased over the last 60 years in proportion to total emissions of CO <sub>2</sub> ( ''high confidence'' ). Although land has been a net sink for CO <sub>2</sub> since around the middle of last century, it was a net source to the atmosphere before that time, primarily as a result of emissions from AFOLU (Le Quéré et al. 2018 <sup>[[#fn:r504|504]]</sup> ).

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