Globally, atmospheric extreme heat events have become increasingly frequent and severe. Hot temperature extremes (HTEs) have already had serious consequences for natural and social systems, triggering responses in lake ecosystems. Global lakes hold approximately 87% of accessible freshwater and provide critical ecosystem services. Satellite data and in-situ measurements suggest that the surface water temperature of global lakes has risen by 0.34 °C per decade since 1985. Although the immediate consequences of extreme weather events are temporary, the cumulative effects of increasingly frequent occurrences may alter the statistical properties of lake surface water temperatures. It is uncertain how contemporary HTEs contribute to global lake surface warming. 

Recently, researchers led by Dr. SHI Kun from China and the United Kingdom collaborated to uncover the impact of HTEs on the long-term trend of lake surface warming in 1,260 lakes worldwide from 1979 to 2022 by using numerical models and satellite observation data. The study was published in Nature Climate Change on September 17.

IMAGE: The contribution of HTEs to summer mean LSWT trend

CREDIT: SHI Kun

The study discovered that HTEs have a considerable impact on the rise in surface water temperatures of the studied lakes from 1979 to 2022. The duration and cumulative intensity of HTEs in the water bodies significantly increased, with average rates of 1.4 days and 0.92 °C day per decade, respectively. Although HTEs accounted for just 7% of total summer days, they contributed 24% of the summer warming trend in lake surfaces, with the most pronounced impact recorded in Europe at 27%. Furthermore, the study discovered that HTEs are key drivers of both the duration and cumulative intensity of lake heatwaves.

“We all witness more hot weathers, but it is uncertain how much they can impact lakes”, said Dr. SHI Kun, corresponding author of the study. The findings of this study highlight the critical role of short-term extreme weather events in shaping the long-term dynamics of lake water temperatures. 

JOURNAL

Nature Climate Change

DOI

10.1038/s41558-024-02122-y

ARTICLE TITLE

Disproportionate impact of atmospheric heat events on lake surface water temperature increases

ARITICLE PUBLICATION DATE

17-September-2024