Hardly a month goes by without a heatwave occurring somewhere on our planet: January? Australia.
Hardly a month goes by without a heatwave occurring somewhere on our planet: January? Australia. February? Brazil. March? Central Asia. And so on. These prolonged periods of intense heat stress are becoming increasingly frequent, posing severe threats to human health, economic productivity, livestock, and ecosystems in a world that is getting warmer – and more humid.
One critical but often overlooked aggravating factor of heatwave impacts is air humidity: High humidity limits the ability of the human body to cool down through sweating, significantly increasing heat stress. This is especially the case in already hot and humid tropical regions because physiological thresholds may be crossed more often there. Compounding this issue, populations are also especially vulnerable in these regions: limited capacities for heatwave prediction, little access to healthcare, drinking water, and electricity, etc. Despite these risks, the underlying drivers of heatwaves remain poorly understood.
Addressing this knowledge gap, UKCEH researchers Dr Guillaume Chagnaud, Prof Christopher Taylor, and Dr Cornelia Klein, in collaboration with researchers at the University of Leeds, used a high-resolution, pan-African climate model simulation to study how localised soil moisture variations influence heatwaves. They showed that under favourable large-scale atmospheric conditions, areas with unusually wet soils spanning just a few 10s of kilometres across – reflecting the width of a typical rain event – can amplify heatwaves locally by 0.5–0.6 degree C.
Read more at: UK Centre for Ecology & Hydrology
Photo Credit: Kanenori via Pixabay
