Editing IPCC:AR6/WGII/Chapter-12 (section)

== 12.2 Summary of AR5 and Recent IPCC Special Reports ==

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CSA shows increasing trends of climatic change and variability and extreme events severely impacting the region, exacerbating problems of rampant and persistent poverty, precarious health systems and water and sanitation services, malnutrition and pollution. Inadequate governance and lack of participation escalates the vulnerability and risk to climate variability and change in the region ( ''high confidence'' ) (WGII AR5 Chapter 27) ( [[#Magrin--2014|Magrin et al., 2014]] ).

Increasing trends in precipitation had been observed in SES (Figure 12.1), in contrast to decreasing trends in CA and central-southern Chile ( ''high confidence'' ) (WGII AR5 Chapter 27) ( [[#Magrin--2014|Magrin et al., 2014]] ). The frequency and intensity of droughts have increased in many parts of SA ( [[#IPCC--2019c|IPCC, 2019c]] ). Warming has been detected throughout CSA, except for a cooling trend reported for the ocean off the Chilean coast.

Climate projections indicate increases in temperature for the entire region by 2100 for RCP4.5 and RCP8.5, but rainfall changes will vary geographically, with a notable reduction of −22% in northeastern Brazil and an increase of +25% in SES. Significant dependency on rainfed agriculture (&gt;30% in Guatemala, Honduras and Nicaragua) indicates high sensitivity to climatic variability and change and represents a challenge for food security ( ''high confidence'' ) (SRCCL Chapter 5, [[#Mbow--2019|Mbow et al., 2019]] ). Undernutrition has worsened since 2014 in CSA (SRCCL Chapter 5, [[#Mbow--2019|Mbow et al., 2019]] ). Evidence of climate-change impacts on food security is emerging from IKLK studies in SA. Municipalities in CA with a high proportion of subsistence crops tend to have fewer resources for adaptation and more vulnerable to climate change (SRCCL Chapter 5, [[#Mbow--2019|Mbow et al., 2019]] ). Rising temperature and decreased rainfall could reduce agricultural productivity by 2030, threatening the food security of the poorest populations (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ). Though reduced suitability and yield for beans, coffee, maize, plantain and rice are expected in CA (SRCCL Chapter 5, [[#Mbow--2019|Mbow et al., 2019]] ), limiting the warming to 1.5°C, compared with 2°C, are projected to result in smaller net reductions in yields of maize, rice, wheat and other cereal crops for CSA ( ''high confidence'' ) (SR15 Chapter 3, [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ). The heat stress is expected to reduce the suitability of Arabica coffee in Mesoamerica, but it can improve in high-latitude areas in SA (SRCCL Chapter 4, [[#Olsson--2019|Olsson et al., 2019]] ). There is ''limited evidence'' that these declines in crop yields may result in significant population displacement from the tropics to the sub-tropics (SR15 Chapter 3, [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ).

There is a ''high confidence'' that heatwaves will increase in frequency, intensity and duration, becoming, under high emission scenarios, extremely long, over 60 d in duration in SA; the risk of wildfires will also increase significantly in SA (SRCCL Chapter 2, [[#Jia--2019|Jia et al., 2019]] ). These processes are leading and will continue to lead to increased desertification that will cost between 8% and 14% of gross agricultural product in many CSA countries (SRCCL Chapter 3, [[#Mirzabaev--2019|Mirzabaev et al., 2019]] ). Distinguishing climate-induced changes from land use changes is challenging, but 5–6% of biomes in SA are expected to change by 2100 due to climate change (SRCCL Chapter 4, [[#Olsson--2019|Olsson et al., 2019]] ).

Changes in weather and climatic patterns are negatively affecting human health in CSA, in part through the emergence of diseases in previously non-endemic areas (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ). Projections of potential impacts of climate change on malaria confirm that weather and climate are among the drivers of geographic range, intensity of transmission, and seasonality; the changes of risk become more complex with additional warming ( ''very high confidence'' ) (SR15 Chapter 3, [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ). There is ''high confidence'' that constraining the warming to 1.5°C would reduce risks for unique and threatened ecosystems safeguarding the services they provide for livelihoods and sustainable development (food, water) in CA and Amazon (SR15 Chapter 5, [[#Roy--2018|Roy et al., 2018]] ).

Observed changes in streamflow and water availability affect vulnerable regions (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ). Glacier mass changes in the Andes in recent decades are among the most negative ones worldwide (SROCC Chapter 2, [[#Hock--2019|Hock et al., 2019]] ). This reduction has modified the frequency, magnitude and location of related natural hazards, while the exposure of people and infrastructure has increased because of growing population, tourism and economic development ( ''high confidence'' ) (SROCC Chapter 2, [[#Hock--2019|Hock et al., 2019]] ).

The negative impacts of climate change in the region are exacerbated by deforestation and land degradation attributed mainly to expansion and intensification of agriculture and cattle ranching, usually under insecure-tenure land. This conversion of natural ecosystems is the main cause of biodiversity and ecosystem loss and is an important source of GHG emissions ( ''high confidence'' ) (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ).

The combination of continued anthropogenic disturbance, particularly deforestation, with global warming may result in dieback of forest in the region ( ''medium confidence'' ) (SR15 Chapter 3, [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ). Losses of biomass as high as 40% are projected in CA with a warming of 3°C–4°C, and the Amazon may experience a significant dieback at similar warming levels (SR15 Chapter 3, [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ). Advances in second-generation bioethanol from sugarcane and other feedstock will be important for mitigation. However, agricultural expansion results in large conversions in tropical dry woodlands and savannahs in SA (Brazilian Cerrado, Caatinga and Chaco) ( ''high confidence'' ) (SRCCL Chapter 1, [[#Arneth--2019|Arneth et al., 2019]] ). The expansion of soybean plantations in the Amazonian state of Mato Grosso in Brazil reached 16.8% yr −1 from 2000 to 2005; and oil palm, a significant biofuel crop, is also linked to recent deforestation in tropical CA (Costa Rica and Honduras) and SA (Colombia and Ecuador), although lower in magnitude compared to deforestation from soybean and cattle ranching (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ).

Ocean and coastal ecosystems in the region already show important changes due to climate change and global warming (SROCC Chapter 5, [[#Bindoff--2019|Bindoff et al., 2019]] ).

Adaptation to future climate change starts by reducing the vulnerability to the present climate considering the deficient welfare of people in the region. Generalising to the region cases of synergies among development, adaptation and mitigation planning requires a governance model where development needs, vulnerability reduction and adaptation strategies are intertwined (WGII AR5 Chapter 27, [[#Magrin--2014|Magrin et al., 2014]] ).

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