Editing IPCC:AR6/WGIII/Chapter-7 (section)

==== 7.2.2.1 Global Net AFOLU CO 2 Flux ====

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Comparison of estimates of the global net AFOLU flux of CO 2 from diverse approaches (Figure 7.4) show differences on the order of several GtCO 2 yr –1 . When considering the reasons for the differences, and an approach to reconcile them ( [[#Grassi--2021|Grassi et al. 2021]] ) ( [[#7.2.2.3|Section 7.2.2.3]] ), there is ''medium confidence'' in the magnitude of the net AFOLU CO 2 flux. There is a discrepancy in the reported CO 2 AFOLU emissions magnitude because alternative methodological approaches that incorporate different assumptions are used ( [[#7.2.2.2|Section 7.2.2.2]] ). While the mean of the bookkeeping and DGVM model’s show a small increase in global CO 2 net emissions since year 2000, individual models suggest opposite trends ( [[#Friedlingstein--2020|Friedlingstein et al. 2020]] ). The latest FAOSTAT and NGHGI estimates show a small reduction in net emission. Overall, the trends are unclear.

Regionally (Figure 7.5), there is ''high confidence'' of net emissions linked to deforestation in Latin America, Africa and South-East Asia from 1990 to 2019. There is ''medium confidence'' in trends indicating a decrease in net emissions in Latin America since 2005 linked to reduced gross deforestation emissions, and a small increase in net emissions related to increased gross deforestation emissions in Africa since 2000 (Figure 7.5). There is ''high confidence'' regarding the net AFOLU CO 2 sink in Europe due to forest regrowth and known other sinks in managed forests, and ''medium confidence'' of a net sink in North America and Eurasia since 2010.

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'''Figure 7.4 |''' '''Global net CO''' 2 '''flux due to AFOLU estimated using different methods for the period 1960 to 2019 (GtCO''' 2 '''y''' '''r''' –1 ''').''' Positive numbers represent emissions. '''Light-blue line:''' The mean from 17 DGVMs all using the same driving data under TrendyV9 used within the Global Carbon Budget 2020 and including different degrees of management ( [[#Bastos--2020|Bastos et al. 2020]] ; [[#Friedlingstein--2020|Friedlingstein et al. 2020]] ). '''Brown line:''' Data downloaded 6 June 2021 from FAOSTAT ( [[#FAO--2021b|FAO 2021b]] ; http://www.fao.org/faostat/ ) comprising: net emissions from (i) forest land converted to other land, (ii) net emissions from organic soils in cropland, grassland and from biomass burning, including peat fires and peat draining ( [[#Prosperi--2020|Prosperi et al. 2020]] ) and (iii) net emissions from forest land remaining forest land, which includes managed forest lands ( [[#Tubiello--2020|Tubiello et al. 2020]] ). '''Yellow''' '''line:''' Net flux estimate from National Greenhouse Gas Inventories (NGHGI) based on country reports to the UNFCCC for LULUCF ( [[#Grassi--2021|Grassi et al. 2021]] ) which include land-use change, and flux in managed lands. '''Red EO line:''' The 2001–2019 average net CO 2 flux from non-intact forest-related emissions and removals based on ground and Earth Observation data (EO) ( [[#Harris--2021|Harris et al. 2021]] ). Data to mask non-intact forest were used in the tropics ( [[#Turubanova--2018|Turubanova et al. 2018]] ) and extra-tropics ( [[#Potapov--2017|Potapov et al. 2017]] ). '''Dark''' '''blue line:''' the mean estimate and minimum and maximum (dark-blue shading) from three bookkeeping models ( [[#Hansis--2015|Hansis et al. 2015]] ; [[#Houghton--2017|Houghton and Nassikas 2017]] ; [[#Gasser--2020|Gasser et al. 2020]] ). These include land cover change (e.g., deforestation, afforestation), forest management including wood harvest and land degradation, shifting cultivation, regrowth of forests following wood harvest or abandonment of agriculture, grassland management, agricultural management. Emissions from peat burning and draining are added from external datasets (see text). Both the DGVM and bookkeeping global data is available at: https://www.icos-cp.eu/science-and-impact/global-carbon-budget/2020 (accessed on 4 October 2021). Data consistent with IPCC AR6 WGI Chapter 5. Dotted lines denote the linear regression from 2000 to 2019. Trends are statistically significant (P &lt;0.05) with exception for the NGHGI trend (P &lt;0.01).

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'''Figure 7.5 | Regional net flux of CO''' 2 '''due to AFOLU estimated using different methods for the period''' '''1990–2019''' '''(GtCO''' 2 '''y''' '''r''' –1 ''').''' Positive numbers represent emissions. The upper-central panel depicts the world map shaded according to the IPCC AR6 regions corresponding to the individual graphs. For each regional panel; '''brown''' '''line:''' Total net flux data from FAOSTAT ( [[#Tubiello--2020|Tubiello et al. 2020]] ); '''yellow line:''' Net emissions estimates from National Greenhouse Gas Inventories based on country reports to the UNFCCC for LULUCF ( [[#Grassi--2021|Grassi et al. 2021]] ); '''dark-blue line:''' The mean estimate and minimum and maximum (dark-blue shading) from three bookkeeping models. ( [[#Hansis--2015|Hansis et al. 2015]] ; [[#Houghton--2017|Houghton and Nassikas 2017]] ; [[#Gasser--2020|Gasser et al. 2020]] ). Regional estimates from bookkeeping models are available at: https://zenodo.org/record/5548333#.YVwJB2LMJPY ( [[#Minx--2021|Minx et al. 2021]] ). See the legend in Figure 7.4 for a detailed explanation of flux components for each dataset.

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