PASADENA, Calif.–Water temperature in major lakes around the world have been steadily increasing over the past 25 years as a result of global climate change, according to a study released today by researchers at NASA’s Jet Propulsion Laboratory in Pasadena.

According to the study, the Earth’s major lakes have warmed by an average of 0.81 degrees per decade, with some warming as much as 1.8 degrees.

Although the warming trend is global, the greatest increases are in the mid-to high-latitudes of the Northern Hemisphere, the study found.

“Our analysis provides a new, independent data source for assessing the impact of climate change over land around the world,” said researcher Philipp Schneider, lead author of the study that was published in the journal Geophysical Research Letters. “The results have implications for lake
ecosystems, which can be adversely affected by even small water temperature changes.”

The study, based on satellite data collected by the National Oceanic and Atmospheric Administration and European Space Agency, measured surface temperatures of 167 large lakes worldwide. The lakes were all generally larger than 193 square miles and located away from shorelines.

According to the report, the largest and most consistent area of warming was in northern Europe, with a weaker trend in southeastern Europe around the Black and Caspian seas and Kazakhstan.

In North America, the warming trend was higher in the southwestern United States than in the Great Lakes region, the study found. The warming was weaker in the tropics and in the mid-latitudes of the Southern Hemisphere.