ABSTRACT
In this paper, the wet-bulb globe temperature (W), considering both temperature and humidity effects, was used as a heat index to quantify the number of annual total heat wave days (HWDs). Changes in surface air temperature, relative humidity, W, and the total number of HWDs in a year were analyzed using multi-model simulations for the reference period (1986–2005) and different greenhouse gas emission scenarios. Our results suggest that HWDs per year will continue to increase throughout the 21st century, and by 2086–2095, approximately one-half of the land area of the earth could be exposed to heat waves for more than 100 days in a year, under RCP 8.5. At the same air temperature, there should be more focus on tropical countries exposed to the greatest increases in HWDs in the future.
