Key risk 1 has cut across humans and ecosystems, and severe consequences are mainly driven by an increasing frequency, intensity and duration of heat extremes and increasing average temperatures  . The risk of human heat stress and mortality is largely influenced by underlying socioeconomic pathways, with consequences being more severe under SSP3, SSP4 and SSP5 scenarios than SSP1  . The SSPs impact natural systems as well but are not yet well studied. The impact of warming in marine systems are often synergistic with SLR in coastal systems and ocean acidification driven by the rise in CO2, while habitat fragmentation and land use have important synergies in terrestrial systems  . More intense heatwaves on land and in the ocean, particularly in Mediterranean Europe (Section 13.4; Cross-Chapter Paper 4; Darmaraki et al., 2019b;
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report