Global warming amplifies outdoor extreme moist heat during the Indian
Summer Monsoon
Abstract
Because of the climatological prevalence of hot, humid conditions, moist
heat extremes are a significant challenge to the health and wellbeing of
the people in India. While research has demonstrated the importance of
summer monsoon to moist heat in India, impact of monsoon-break and warm
spells in modulating extreme moist heat regionally has not been fully
investigated. Here we investigate moist heat extremes, as measured by
the Wet-Bulb Globe Temperature (WBGT) metric, specifically during
monsoon and monsoon-break periods and find that they pose a major threat
to physical labor and health relative to other seasons. During the
1951-2020 break period, an increasing trend in areas exposed
(~42.76 million km2), representing at least 670 million
people, were exposed to extreme and detrimental WBGT values
>31°C. Our results imply that future studies on extreme
moist heat must pay close attention to the variation of weather systems
on synoptic to subseasonal time scales that are superimposed on the
seasonal monsoon migration.