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

===== Farming system approaches can benefit mitigation and adaptation =====

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Farming system approaches can be a significant contributor to mitigation pathways. These practices (which are not mutually exclusive) include agroecology, conservation agriculture, integrated production systems and organic farming (Box 7.5). Such methods have potential to sequester significant amounts of soil carbon ( [[IPCC:Wg3:Chapter:Chapter-7#7.4.3.1|Section 7.4.3.1]] ) as well as reduce emissions from on-field practices such as rice cultivation, fertilizer management, and manure management ( [[IPCC:Wg3:Chapter:Chapter-7#7.4.3|Section 7.4.3]] ) with total mitigation potential of 3.9 ± 0.2 GtCO 2 -eq yr –1 (Chapter 7). Critically, these approaches may have significant benefits in terms of adaptation and other development goals.

Farming system approaches to agricultural mitigation have a wide variety of co-benefits and trade-offs. Indeed, there are conceptual formulations for these practices in which the co-benefits are more of a focus, such as climate-smart agriculture (CSA) which ties mitigation to adaptation through its three pillars of increased productivity, mitigation, and adaptation ( [[#Lipper--2014|Lipper et al. 2014]] ). The ‘4 per 1000’ goal to increase soil carbon by 0.4% per year ( [[#Soussana--2019|Soussana et al. 2019]] ) is compatible with the three pillars of CSA. Sustainable intensification, a framework which centers around a need for increased agricultural production within environmental constraints also complements CSA ( [[#Campbell--2014|Campbell et al. 2014]] ). The literature reports examples of mitigation co-benefits of adaptation actions, with evidence from various regions ( [[#Thornton--2015|Thornton and Herrero 2015]] ; [[#Thornton--2018|Thornton et al. 2018]] ) (Chapter 7).

Conservation agriculture, promoted for improving agricultural soils and crop diversity ( [[#Powlson--2016|Powlson et al. 2016]] ) can help build adaptive capacity ( [[#Smith--2017|Smith et al. 2017]] ; [[#Pradhan--2018a|Pradhan et al. 2018a]] ) and yield mitigation co-benefits through improved fertiliser use or efficient use of machinery and fossil fuels ( [[#Harvey--2014|Harvey et al. 2014]] ; [[#Cui--2018|Cui et al. 2018]] ; [[#Pradhan--2018a|Pradhan et al. 2018a]] ).

There is a complex set of barriers to implementation of farming-system approaches for climate mitigation ( [[IPCC:Wg3:Chapter:Chapter-7#7.6.4|Section 7.6.4]] ), suggesting a need for deliberate shifts in development pathways to achieve significant progress in this sector. The link between NDCs and mitigation in the land use sector can provide impetus for such policies. For example, there are multiple agricultural mitigation options that southeast Asian countries could use to meet NDCs that would have an important adaptive impact (Amjath-Babu et al. 2019).

Some agricultural practices considered sustainable have trade-offs, and their implementation can have negative effects on adaptation or other ecosystem services. Fast-growing tree monocultures or biofuel crops may enhance carbon stocks but reduce downstream water availability and decrease availability of agricultural land ( [[#Windham-Myers--2018|Windham-Myers et al. 2018]] ; [[#Kuwae--2019|Kuwae and Hori 2019]] ). In some dry environments similarly, agroforestry can increase competition with crops and pastures, decreasing productivity, and reduce catchment water yield ( [[#Schrobback--2011|Schrobback et al. 2011]] ).

Agricultural practices can adapt to climate change while decreasing CO 2 emissions on the farm field. However, if such a practice leads to lower yields, interconnections of the global agricultural system can lead to land use change elsewhere and a net increase in GHG emissions ( [[#Erb--2016|Erb et al. 2016]] ). Implementation of sustainable agriculture can increase or decrease yields depending on context ( [[#Pretty--2006|Pretty et al. 2006]] ).

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