MULTI-MEGACITY INVESTIGATION OF HEAT WAVE EVENTS UNDER VARIOUS CLIMATE CHANGE AND URBANIZATION SCENARIOS

Abstract

 In 2022, intense heat waves occur all around the world. In this study, we project these heat waves into the future with futuristic projection of hourly varying spatially distributed anthropogenic heat for three megacities—Delhi, London, and Tokyo. Different future climate forcing (CMIP5 and CMIP6) was also compared. We found that if similar heat waves occur in the future, they may be 0.8 to 1.5 °C hotter than the past events, on average. Urbanization in Delhi may severely worsen the heat wave, while projected decrease in energy usage in London and Tokyo may make the heat waves less severe. For the concerned heat wave events, urbanization effect was also found to be stronger in nighttime than daytime and exhibits large spatial heterogeneity and dependence on background climate forcing. Difference between CMIP5 and CMIP6 was significant but was much less than the difference between CMIP5/CMIP6 and the present.