The study is the largest of its kind and the first to use a combination of satellite temperature data and long-term ground measurements. A total of 235 lakes, representing more than half of the world’s freshwater supply, were monitored for at least 25 years. The research, published in Geophysical Research Letters, was announced today at the American Geophysical Union meeting.
The study, which was funded by NASA and the National Science Foundation, found lakes are warming an average of 0.61 degrees Fahrenheit (0.34 degrees Celsius) each decade. That’s greater than the warming rate of either the ocean or the atmosphere, and it can have profound effects, the scientists say.
Temperature increases close to or above the average .61 degrees F rise were seen in some of the world’s most popular waters, including Lake Tahoe (+.97 F by hand, +1.28 by satellite), the Dead Sea (+1.13 F), two reservoirs serving New York City, Seattle’s Lake Washington (+.49 F), and the Great Lakes Huron (+1.53 F by hand, +.79 by satellite), Michigan (+.76 F by hand, +.36 by satellite), Ontario (+.59 F) and Superior (+2.09 F by hand measurement, +1.44 F by satellite).