Editing IPCC:AR6/WGII/Cross-Chapter-Paper-4 (section)

=== CCP4.1.2 Main Findings from Previous Assessments ===

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All previous assessments of climate change for the Mediterranean Basin and its sub-regions indicate ongoing warming of the atmosphere and the sea, as well as projected warming and changes in rainfall ( [[#Stocker--2013|Stocker et al., 2013]] ; [[#Cherif--2020|Cherif et al., 2020]] ). The projected increase in climate hazards, in combination with high regional vulnerability and exposure make it a prominent ‘climate change hotspot’ ( [[#Giorgi--2006|Giorgi, 2006]] ), with a large number of vulnerable natural systems and socioeconomic sectors ( [[#Field--2014|Field et al., 2014]] ; [[#MedECC--2020|MedECC, 2020]] ). In addition to high temperatures, the main risk factor identified is drought, generally expected to increase in the region, significant already at global warming of only 1.5°C, reaching, for higher warming levels, intensities unprecedented during the past 10 ka ( [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ). In Southern Europe and North Africa, groundwater recharge and soil water content will consequently decline, especially during summer ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Niang--2014|Niang et al., 2014]] ).

With the changing climate, marine ecosystems have already undergone changes in structure, including the spread of tropical species from the Atlantic Ocean and the Red Sea ( ''high confidence'' ) and mass mortality in at least 25 invertebrate species, threatening, along with ocean acidification, marine ecosystems, including seagrass meadows ( [[#Hoegh-Guldberg--2014|Hoegh-Guldberg et al., 2014]] ; [[#Nurse--2014|Nurse et al., 2014]] ; [[#Pörtner--2014|Pörtner et al., 2014]] ; [[#Wong--2014|Wong et al., 2014]] ). Endemic marine species are at higher risk of extinction due to limited possibilities for migrating northward ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Poloczanska--2014|Poloczanska et al., 2014]] ; [[#Balzan--2020|Balzan et al., 2020]] ). Southern and eastern Mediterranean coastal systems with narrow dune belts and often rapid urbanisation are vulnerable to both warming and sea level rise ( [[#Seneviratne--2012|Seneviratne et al., 2012]] ; [[#Wong--2014|Wong et al., 2014]] ; [[#Balzan--2020|Balzan et al., 2020]] ).

Most Mediterranean land ecosystems are impacted negatively by drier conditions, causing the ranges of many endemic species to shrink, and the health and growth rates of trees to decline ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Niang--2014|Niang et al., 2014]] ; [[#Nurse--2014|Nurse et al., 2014]] ; [[#Settele--2014|Settele et al., 2014]] ). Climate change is expected to increase wildfire risk in the region ( [[#Kovats--2014|Kovats et al., 2014]] ), although earlier estimates of burnt area have been reduced in the most recent assessments to approx. 40–100%, considering that prevention and mitigation actions have successfully reduced this risk so far ( [[#Balzan--2020|Balzan et al., 2020]] ). Wetlands and mountain summits are hotspots for biodiversity loss and extinctions ( ''medium confidence'' ) ( [[#Jiménez%20Cisneros--2014|Jiménez Cisneros et al., 2014]] ; [[#Nurse--2014|Nurse et al., 2014]] ; [[#IPBES--2018a|IPBES, 2018a]] ; [[#IPBES--2018b|IPBES, 2018b]] ; [[#Balzan--2020|Balzan et al., 2020]] ). Along with unsustainable land use practices, climate change is projected to increase soil erosion in semiarid areas ( [[#Jiménez%20Cisneros--2014|Jiménez Cisneros et al., 2014]] ).

The increasing water scarcity was found to be a significant threat to agriculture ( [[#Jiménez%20Cisneros--2014|Jiménez Cisneros et al., 2014]] ; [[#Kovats--2014|Kovats et al., 2014]] ; [[#Niang--2014|Niang et al., 2014]] ; [[#Mrabet--2020|Mrabet et al., 2020]] ). Associated with increased extreme temperatures, the Mediterranean is expected to become less attractive for tourism ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Nurse--2014|Nurse et al., 2014]] ; [[#Wong--2014|Wong et al., 2014]] ; [[#Dos%20Santos--2020|Dos Santos et al., 2020]] ). Several critical risks for human health increase due to climate change, including heat waves and vector-borne diseases ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Nurse--2014|Nurse et al., 2014]] ; [[#Linares--2020|Linares et al., 2020]] ). Adaptation options have been identified for many risks (buildings, water management, coastal protection, etc.) ( [[#Murray--2012|Murray et al., 2012]] ; [[#Revi--2014|Revi et al., 2014]] ; [[#Wong--2014|Wong et al., 2014]] ). There are synergies between adaptation and mitigation, for example, renewable energies or nature-based solutions focused on the conservation and restoration of ecosystems ( [[#Nurse--2014|Nurse et al., 2014]] ; [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ; [[#Vafeidis--2020|Vafeidis et al., 2020]] ).

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