Editing IPCC:AR6/SRCCL/Chapter-4 (section)

=== 4.8.3 Reducing deforestation and forest degradation and increasing afforestation ===

<div id="section-4-8-3-reducing-deforestation-and-forest-degradation-and-increasing-afforestation-block-1"></div>

Improved stewardship of forests through reduction or avoidance of deforestation and forest degradation, and enhancement of forest carbon stocks can all contribute to land-based natural climate solutions (Angelsen et al. 2018 <sup>[[#fn:r1034|1034]]</sup> ; Sonwa et al. 2011 <sup>[[#fn:r1035|1035]]</sup> ; Griscom et al. 2017 <sup>[[#fn:r1036|1036]]</sup> ). While estimates of annual emissions from tropical deforestation and forest degradation range widely from 0.5 to 3.5 GtC yr <sup>–1</sup> (Baccini et al. 2017 <sup>[[#fn:r1037|1037]]</sup> ; Houghton et al. 2012 <sup>[[#fn:r1038|1038]]</sup> ; Mitchard 2018 <sup>[[#fn:r1039|1039]]</sup> ; see also Chapter 2), they all indicate the large potential to reduce annual emissions from deforestation and forest degradation. Recent estimates of forest extent for Africa in 1900 may result in downward adjustments of historic deforestation and degradation emission estimates (Aleman et al. 2018 <sup>[[#fn:r1040|1040]]</sup> ). Emissions from forest degradation in non-Annex I countries have declined marginally from 1.1 GtCO <sub>2</sub> yr <sup>–1</sup> in 2001–2010 to 1 GtCO <sub>2</sub> yr <sup>–1</sup> in 2011–2015, but the relative emissions from degradation compared to deforestation have increased from a quarter to a third (Federici et al. 2015 <sup>[[#fn:r1041|1041]]</sup> ). Forest sector activities in developing countries were estimated to represent a technical mitigation potential in 2030 of 9 GtCO <sub>2</sub> (Miles et al. 2015). This was partitioned into reduction of deforestation (3.5 GtCO <sub>2</sub> ), reduction in degradation and forest management (1.7 GtCO <sub>2</sub> ) and afforestation and reforestation (3.8 GtCO <sub>2</sub> ). The economic mitigation potential will be lower than the technical potential (Miles et al. 2015 <sup>[[#fn:r1042|1042]]</sup> ).

Natural regeneration of second-growth forests enhances carbon sinks in the global carbon budget (Chazdon and Uriarte 2016 <sup>[[#fn:r1043|1043]]</sup> ). In Latin America, Chazdon et al. (2016) <sup>[[#fn:r1044|1044]]</sup> estimated that, in 2008, second-growth forests (up to 60 years old) covered 2.4 Mkm <sup>2</sup> of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate 8.5 GtC in above-ground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO <sub>2</sub> sequestration of 31.1 GtCO <sub>2</sub> (Chazdon et al. 2016b). While above-ground biomass carbon stocks are estimated to be declining in the tropics, they are increasing globally due to increasing stocks in temperate and boreal forests (Liu et al. 2015b), consistent with the observations of a global land sector carbon sink (Le Quéré et al. 2013 <sup>[[#fn:r1045|1045]]</sup> ; Keenan et al. 2017 <sup>[[#fn:r1046|1046]]</sup> ; Pan et al. 2011).

Moving from technical mitigation potentials (Miles et al. 2015 <sup>[[#fn:r1047|1047]]</sup> ) to real reduction of emissions from deforestation and forest degradation required transformational changes (Korhonen-Kurki et al. 2018 <sup>[[#fn:r1048|1048]]</sup> ). This transformation can be facilitated by two enabling conditions: the presence of already initiated policy change; or the scarcity of forest resources combined with an absence of any effective forestry framework and policies. These authors and others (Angelsen et al. 2018 <sup>[[#fn:r1049|1049]]</sup> ) found that the presence of powerful transformational coalitions of domestic pro-REDD+ (the United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries) political actors combined with strong ownership and leadership, regulations and law enforcement, and performance-based funding, can provide a strong incentive for achieving REDD+ goals.

Implementing schemes such as REDD+ and various projects related to the voluntary carbon market is often regarded as a no-regrets investment (Seymour and Angelsen 2012 <sup>[[#fn:r1050|1050]]</sup> ) but the social and ecological implications (including those identified in the Cancun Safeguards) must be carefully considered for REDD+ projects to be socially and ecologically sustainable (Jagger et al. 2015 <sup>[[#fn:r1051|1051]]</sup> ). In 2018, 34 countries have submitted a REDD+ forest reference level and/ or forest reference emission level to the United Nations Framework Convention on Climate Change (UNFCCC). Of these REDD+ reference levels, 95% included the activity ‘reducing deforestation’ while 34% included the activity ‘reducing forest degradation’ (FAO 2018). Five countries submitted REDD+ results in the technical annex to their Biennial Update Report totalling an emission reduction of 6.3 GtCO <sub>2</sub> between 2006 and 2015 (FAO 2018).

Afforestation is another mitigation activity that increases carbon sequestration (Cross-Chapter Box 2 in Chapter 1). Yet, it requires careful consideration about where to plant trees to achieve potential climatic benefits, given an altering of local albedo and turbulent energy fluxes and increasing night-time land surface temperatures (Peng et al. 2014 <sup>[[#fn:r1052|1052]]</sup> ). A recent hydro-climatic modelling effort has shown that forest cover can account for about 40% of the observed decrease in annual runoff (Buendia et al. 2016 <sup>[[#fn:r1053|1053]]</sup> ). A meta-analysis of afforestation in Northern Europe (Bárcena et al. 2014 <sup>[[#fn:r1054|1054]]</sup> ) concluded that significant soil organic carbon sequestration in Northern Europe occurs after afforestation of croplands but not grasslands. Additional sequestration occurs in forest floors and biomass carbon stocks. Successful programmes of large-scale afforestation activities in South Korea and China are discussed in-depth in a special case study (Section 4.9.3).

The potential outcome of efforts to reduce emissions from deforestation and degradation in Indonesia through a 2011 moratorium on concessions to convert primary forests to either timber or palm oil uses was evaluated against rates of emissions over the period 2000 to 2010. The study concluded that less than 7% of emissions would have been avoided had the moratorium been implemented in 2000 because it only curtailed emissions due to a subset of drivers of deforestation and degradation (Busch et al. 2015 <sup>[[#fn:r1055|1055]]</sup> ).

In terms of ecological integrity of tropical forests, the policy focus on carbon storage and tree cover can be problematic if it leaves out other aspects of forests ecosystems, such as biodiversity – and particularly fauna (Panfil and Harvey 2016 <sup>[[#fn:r1056|1056]]</sup> ; Peres et al. 2016 <sup>[[#fn:r1057|1057]]</sup> ; Hinsley et al. 2015 <sup>[[#fn:r1058|1058]]</sup> ). Other concerns of forest-based projects under the voluntary carbon market are potential negative socio-economic side effects (Edstedt and Carton 2018 <sup>[[#fn:r1059|1059]]</sup> ; Carton and Andersson 2017 <sup>[[#fn:r1060|1060]]</sup> ; Osborne 2011 <sup>[[#fn:r1061|1061]]</sup> ; Scheidel and Work 2018 <sup>[[#fn:r1062|1062]]</sup> ; Richards and Lyons 2016 <sup>[[#fn:r1063|1063]]</sup> ; Borras and Franco 2018 <sup>[[#fn:r1064|1064]]</sup> ; Paladino and Fiske 2017 <sup>[[#fn:r1065|1065]]</sup> ) and leakage (particularly at the subnational scale), that is, when interventions to reduce deforestation or degradation at one site displace pressures and increase emissions elsewhere (Atmadja and Verchot 2012 <sup>[[#fn:r1066|1066]]</sup> ; Phelps et al. 2010 <sup>[[#fn:r1067|1067]]</sup> ; Lund et al. 2017 <sup>[[#fn:r1068|1068]]</sup> ; Balooni and Lund 2014 <sup>[[#fn:r1069|1069]]</sup> ).

Maintaining and increasing forest area, in particular native forests rather than monoculture and short-rotation plantations, contributes to the maintenance of global forest carbon stocks (Lewis et al. 2019 <sup>[[#fn:r1070|1070]]</sup> ) ( ''robust evidence, high agreement'' ).

<span id="sustainable-forest-management-sfm-and-co2-removal-cdr-technologies"></span>