Heat-related mortality is assessed to increase from high to very high by 3ºC under SSP3, a socioeconomic scenario with large challenges to adaptation . SRCCL assessed that very high risks would be reached in association with wildfire above 3ºC of global warming . Chapter 2 has assessed that risk of fire weather itself transitions from high to very high over the range 3℃ to 4.5℃ warming . Matthews et al.  show that, at 1.5℃ of global warming, about 40% of all megacities would be affected at least 1 d yr-1 with a heat index above 40.6°C . This number would reach about 65% of megacities at 2.7ºC and close to 80% at 4ºC. In addition, there is evidence for a higher risk of concurrent heat extremes at different locations with increasing global warming , meaning that several cities could be affected by deadly heatwaves simultaneously. Laufkötter et al.  found that marine heatwave events would become annual to decadal events under 3ºC of global warming, with consequences for aquaculture . Gaupp et al.  conclude that risks of simultaneous crop failure across worldwide breadbasket regions, due to changes in maximum temperatures in the crop-growth-relevant season or cumulative precipitation in relevant time frames, increase disproportionately between 1.5℃ and 2℃ of global warming. Populations exposed to extreme weather and climate events may consume inadequate or insufficient food, leading to malnutrition and increasing the risk of disease . Hence,
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report