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

==== 7.4.2.1 Reduce Deforestation and Degradation ====

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'''Activities, co-benefits, risks and implementation opportunities and barriers.''' Reducing deforestation and forest degradation conserves existing carbon pools in forest vegetation and soil by avoiding tree cover loss and disturbance. Protecting forests involves controlling the drivers of deforestation (such as commercial and subsistence agriculture, mining, urban expansion) and forest degradation (such as overharvesting including fuelwood collection, poor harvesting practices, overgrazing, pest outbreaks, and extreme wildfires), as well as by establishing well designed, managed and funded protected areas ( [[#Barber--2014|Barber et al. 2014]] ), improving law enforcement, forest governance and land tenure, supporting community forest management and introducing forest certification (P. [[#Smith--2019|Smith et al. 2019]] a). Reducing deforestation provides numerous and substantial co-benefits, preserving biodiversity and ecosystem services (e.g., air and water filtration, water cycling, nutrient cycling) more effectively and at lower costs than afforestation/reforestation ( [[#Jia--2019|Jia et al. 2019]] ). Potential adverse side effects of these conservation measures include reducing the potential for agriculture land expansion, restricting the rights and access of local people to forest resources, or increasing the dependence of local people to insecure external funding. Barriers to implementation include unclear land tenure, weak environmental governance, insufficient funds, and increasing pressures associated to agriculture conversion, resource exploitation and infrastructure development (Sections 7.3 and 7.6).

'''Conclusions from AR5 and IPCC Special Reports (SR1.5, SROCC''' '''and SRCCL); mitigation potential, costs, and pathways.''' Reducing deforestation and forest degradation represents one of the most effective options for climate change mitigation, with technical potential estimated at 0.4–5.8 GtCO 2 yr –1 by 2050 ( ''high confidence'' ) (SRCCL, Chapters 2 and 4, and Table 6.14). The higher technical estimate represents a complete halting of land-use conversion in forests and peatland forests (i.e., assuming recent rates of carbon loss are saved each year) and includes vegetation and soil carbon pools. Ranges of economic potentials for forestry ranged in AR5 from 0.01–1.45 GtCO 2 yr –1 for USD20 tCO 2 –1 to 0.2–13.8 GtCO 2 yr –1 for USD100 tCO 2 –1 by 2030 with reduced deforestation dominating the forestry mitigation potential LAM and MAF, but very little potential in OECD-1990 and EIT (IPCC AR5).

'''Developments since AR5 and IPCC Special Reports (SR1.5, SROCC and SRCCL).''' Since the SRCCL, several studies have provided updated and convergent estimates of economic mitigation potentials by region ( [[#Busch--2019|Busch et al. 2019]] ; [[#Griscom--2020|Griscom et al. 2020]] ; [[#Austin--2020|Austin et al. 2020]] ; [[#Roe--2021|Roe et al. 2021]] ). Tropical forests and savannas in Latin America provide the largest share of mitigation potential (3.9 GtCO 2 yr –1 technical, 2.5 GtCO 2 yr –1 at USD100 tCO 2 –1 ) followed by South-East Asia (2.2 GtCO 2 yr –1 technical, 1.5 GtCO 2 yr –1 at USD100 tCO 2 –1 ) and Africa (2.2 GtCO 2 yr –1 technical, 1.2 GtCO 2 yr –1 at USD100 tCO 2 –1 ) ( [[#Roe--2021|Roe et al. 2021]] ). Tropical forests continue to account for the highest rates of deforestation and associated GHG emissions. While deforestation shows signs of decreasing in several countries, in others, it continues at a high rate or is increasing ( [[#Turubanova--2018|Turubanova et al. 2018]] ). Between 2010–2020, the rate of net forest loss was 4.7 Mha yr –1 with Africa and South America presenting the largest shares (3.9 Mha and 2.6 Mha, respectively) ( [[#FAO--2020a|FAO 2020a]] ).

A major uncertainty in all studies on avoided deforestation potential is their reliance on future reference levels that vary across studies and approaches. If food demand increases in the future, for example, the area of land deforested will likely increase, suggesting more technical potential for avoiding deforestation. Transboundary leakage due to market adjustments could also increase costs or reduce effectiveness of avoiding deforestation (e.g., [[#Ingalls--2018|Ingalls et al. 2018]] ; [[#Gingrich--2019|Gingrich et al. 2019]] ). Regarding forest regrowth, there are uncertainties about the time for the secondary forest carbon saturation ( [[#Houghton--2017|Houghton and Nassikas 2017]] ; [[#Zhu--2018|Zhu et al. 2018]] ). Permanence of avoided deforestation may also be a concern due to the impacts of climate change and disturbance of other biogeochemical cycles on the world’s forests that can result in future potential changes in terrestrial ecosystem productivity, climate-driven vegetation migration, wildfires, forest regrowth and carbon dynamics ( [[#Ballantyne--2012|Ballantyne et al. 2012]] ; [[#Kim--2017b|Kim et al. 2017b]] ; [[#Lovejoy--2018|Lovejoy and Nobre 2018]] ; [[#Aragão--2018|Aragão et al. 2018]] ).

'''Critical assessment and conclusion.''' Based on studies since AR5, the technical mitigation potential for reducing deforestation and degradation is significant, providing 4.5 (2.3–7) GtCO 2 yr –1 globally by 2050, of which 3.4 (2.3–6.4) GtCO 2 yr –1 is available at below USD100 tCO 2 –1 ( ''medium confidence'' ) (Figure 7.11). Over the last decade, hundreds of subnational initiatives that aim to reduce deforestation related emissions have been implemented across the tropics ( [[#7.6|Section 7.6]] ). Reduced deforestation is a significant piece of the NDCs in the Paris Agreement ( [[#Seddon--2020|Seddon et al. 2020]] ) and keeping the temperature below 1.5°C ( [[#Crusius--2020|Crusius 2020]] ). Conservation of forests provides multiple co-benefits linked to ecosystem services, biodiversity and sustainable development ( [[#7.6|Section 7.6]] .). Still, ensuring good governance, accountability (e.g., enhanced monitoring and verification capacity; [[#Bos--2020|Bos 2020]] ), and the rule of law are crucial for implementing forest-based mitigation options. In many countries with the highest deforestation rates, insecure land rights often are significant barriers for forest-based mitigation options (Gren and Zeleke 2016; [[#Essl--2018|Essl et al. 2018]] ).

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