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Irreversible hotter and drier climate over inner East Asia

ScienceDaily (November 27, 2020 )

Titre : Irreversible hotter and drier climate over inner East Asia Heatwaves pushing Mongolia’s climate to a tipping point

ScienceDaily (November 27, 2020 )

Researchers warn that heatwaves and concurrent droughts of Mongolia’s semi-arid plateau have increased significantly during the past two decades, with troubling implications for the future. The change also has ramifications for atmospheric conditions across the Northern Hemisphere.

Mongolia’s semi-arid plateau may soon become as barren as parts of the American Southwest due to a "vicious cycle" of heatwaves — that exacerbates soil drying, and ultimately produces more heatwaves — according to an international group of climate scientists.

According to the study’s findings, the record high temperatures in the region are accelerated by soil drying, and together these changes are magnifying the decline of soil water. "The result," coauthor Deliang Chen at Sweden’s University of Gothenburg said, "is more heatwaves, which means more soil water losses, which means more heatwaves — and where this might end, we cannot say."

When soil is wet, evaporation cools air at the surface. However, when soil no longer has any moisture, heat transfers directly to the air. In their paper, Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point, the authors state that in the past 260 years, only recent decades "show significant anticorrelation between heatwave frequency and soil moisture, alongside a radical decline in soil moisture fluctuation." The scientists note that a series of recent heatwaves in Europe and North America reveal the connection with near-surface air and soil moisture and suggest that "the semi-arid climate of this region has entered a new regime in which soil moisture no longer mitigates anomalously high air temperature."

Story Source  : Utah State University

Annonce (ScienceDaily)

Page publiée le 27 juin 2021