The world is not only getting hotter but also more humid and new research shows people living in areas where humid-heat extremes are already a significant hazard are bearing the brunt of the impact.

Their study, published earlier this month in the journal Geophysical Research Letters, presents the timing, frequency, and severity of extreme humid-heat and dry-heat events and recent trends using hourly data at a spatial resolution of ~ 25 km or 15.5 mi.

«We identify a greater increase in population exposure to humid-heat as compared to dry-heat, emphasizing the importance of understanding humidity changes in a warming world,» said study lead author Cassandra Rogers, a postdoctoral research associate in the WSU Vancouver School of the Environment.

Most of Europe, northern South America, Africa, the Arabian Peninsula and the island chains between the Indian and Pacific Oceans, as well as the Northern Hemisphere oceans, have experienced statistically significant increases in both dry and humid-heat extremes, according to the researchers’ analysis.

However, a few regions of the planet showed trends that are particularly worrisome.

«For example, increases in the occurrence of humid-heat were strongest over highly populous regions in South and Southeast Asia and southeastern U.S. where changes in dry-heat frequency, as measured by temperature alone, are small or non-significant,» said study coauthor Deepti Singh, an assistant professor in the WSU Vancouver School of the Environment.

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Materials provided by Washington State University. Original written by Will Ferguson. Note: Content may be edited for style and length.