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

==== 7.6.5.1 Ecosystem Services ====

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An evaluation of eighteen ecosystem services over the past five decades (1970–2019) found only four (agricultural production, fish harvest, bioenergy production and harvest of materials) to demonstrate increased performance, while the remaining fourteen, mostly concerning regulating and non-material contributions, were found to be in decline (IPBES 2019a). The value of global agricultural output (over USD3.54 trillion in 2018) had increased approximately threefold since 1970, and roundwood production (industrial roundwood and fuelwood) by 27%, between 1980 to 2018, reaching some 4 billion m 3 in 2018. However, the positive trends in these four ecosystem services does not indicate long-term sustainability. If increases in agricultural production are realised through forest clearance or through increasing energy-intensive inputs, gains are likely to be unsustainable in the long run. Similarly, an increase in fish production may involve overfishing, leading to local species declines which also impacts fish prices, fishing revenues, and the well-being of coastal and fishing communities ( [[#Sumaila--2020|Sumaila and Lam 2020]] ). Climate change and other drivers are likely to affect future fish catch potential, although impacts will differ across regions ( [[#Sumaila--2017|Sumaila et al. 2017]] ; [[#Domke--2019|Domke et al. 2019]] ).

The increasing trend in aquaculture production especially in South and South-East Asia through intensive methods affects existing food production and ecosystems by diverting rice fields or mangroves ( [[#Bhattacharya--2011|Bhattacharya and Ninan 2011]] ). Although extensive traditional fish farming of carp in central Europe can contribute to landscape management, enhance biodiversity and provide ecosystem services, there are several barriers to scale up production due to strict EU environmental regulations, vulnerability to extreme weather events, and to avian predators that are protected by EU laws, and disadvantages faced by small-scale enterprises that dominate the sector (European-Commission 2021). Bioenergy production may have high opportunity costs in land-scarce areas and compete with land used for food production which threatens food security and affects the poor and vulnerable. But these impacts will differ across scale, contexts and other factors.

Currently, land degradation is estimated to have reduced productivity in 23% of the global terrestrial area, and between USD235 billion and USD577 billion in annual global crop output is at risk because of pollinator loss (IPBES 2019a). The global trends reviewed above are based on data from 2000 studies. It is not clear whether the assessment included a quality control check of the studies evaluated and suffer from aggregation bias. For instance, a recent meta-analysis of global forest valuation studies noted that many studies reviewed had shortcomings such as failing to clearly mention the methodology and prices used to value the forest ecosystem services, double counting, data errors, and so on ( [[#Ninan--2013|Ninan and Inoue 2013]] ). Furthermore, the criticisms against the paper by ( [[#Costanza--1997|Costanza et al. 1997]] ), such as ignoring ecological feedbacks and non-linearities that are central to the processes that link all species to each other and their habitats, ignoring substitution effects may also apply to the global assessment ( [[#Smith--1997|Smith 1997]] ; [[#Bockstael--2000|Bockstael et al. 2000]] ; [[#Loomis--2000|Loomis et al. 2000]] ). Land degradation has had a pronounced impact on ecosystem functions worldwide (IPBES 2018e). Net primary productivity of ecosystem biomass and of agriculture is presently lower than it would have been under a natural state on 23% of the global terrestrial area, amounting to a 5% reduction in total global net primary productivity (IPBES 2018e). Over the past two centuries, soil organic carbon, an indicator of soil health, has seen an estimated 8% loss globally (176 GtC) from land conversion and unsustainable land management practices (IPBES 2018e). Projections to 2050 predict further losses of 36 GtC from soils, particularly in sub-Saharan Africa. These losses are projected to come from the expansion of agricultural land into natural areas (16 GtC), degradation due to inappropriate land management (11 GtC) and the draining and burning of peatlands (9 GtC) and melting of permafrost (IPBES 2018e). Trends in biodiversity measured by the global living planet index between 1970 to 2016 indicate a 68% decline in monitored population of mammals, birds, amphibians, reptiles, and fish ( [[#WWF--2020|WWF 2020]] ). FAO’s recent report on the state of the world’s biodiversity for food and agriculture points to an alarming decline in biodiversity for food and agriculture including associated biodiversity such as pollination services, microorganisms which are essential for production systems ( [[#FAO--2019d|FAO 2019d]] ). These suggest that overall ecosystem health is consistently declining with adverse consequences for good quality of life, human well-being, and sustainable development.

Although numerous studies have estimated the value of ecosystem services for different sites, ecosystems, and regions, these studies mostly evaluate ecosystem services at a single point in time ( [[#Costanza--1997|Costanza et al. 1997]] ; [[#Xue--2001|Xue and Tisdell 2001]] ; [[#Nahuelhual--2007|Nahuelhual et al. 2007]] ; [[#de%20Groot--2012|de Groot et al. 2012]] ; [[#Ninan--2016|Ninan and Kontoleon 2016]] ). The few studies that have assessed the trends in the value of ecosystem services provided by different ecosystems across regions and countries indicate a declining trend ( [[#Costanza--2014|Costanza et al. 2014]] ; [[#Kubiszewski--2017|Kubiszewski et al. 2017]] ). Land-use change is a major driver behind loss of biodiversity and ecosystem services in most regions (IPBES 2018b; IPBES 2018c, IPBES 2018d, [[#Rice--2018|Rice et al. 2018]] ). Projected impacts of land-use change and climate change on biodiversity and ecosystem services (material and regulating services) between 2015 to 2050 were assessed to have relatively less negative impacts under global sustainability scenarios as compared to regional competition and economic optimism scenarios (IPBES 2019a). The projected impacts were based on a subset of Shared Socio-economic Pathway (SSP) scenarios and GHG emissions trajectories (RCP) developed in support of IPCC assessments. There are synergies, trade-offs and co-benefits between ecosystem services and mitigation options with impacts on ecosystem services differing by scale and contexts ( ''high confidence'' ). Measures such as conservation agriculture, agroforestry, soil and water conservation, afforestation, adoption of silvopastoral systems, can help minimise trade-offs between mitigations options and ecosystem services ( [[#Duguma--2014|Duguma et al. 2014]] ). Climate-smart agriculture (CSA) is being promoted to enable farmers to make agriculture more sustainable and adapt to climate change (Box 7.4). However, experience with CSA in Africa has not been encouraging. For instance, a study of climate-smart cocoa production in Ghana shows that due to lack of tenure (tree) rights, bureaucratic and legal hurdles in registering trees in cocoa farms, and other barriers small cocoa producers could not realise the project benefits (Box 7.13). Experience of CSA in some other sub-Saharan African countries and other countries such as Belize too has been constrained by weak extension systems and policy implementation, and other barriers ( [[#Arakelyan--2017|Arakelyan et al. 2017]] ; [[#Kongsager--2017|Kongsager 2017]] ).

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