US scientists report that lakes worldwide are warming by an average of more than 1°C every 30 years, faster than the warming rate of either the ocean or the atmosphere.
The warming is expected to increase algal blooms and to mean global emissions of methane, a greenhouse gas 25 times more potent than carbon dioxide over a century, will increase by 4% over the next decade. Over a 20-year period, methane is 84 times more powerful than CO2.
The rapid warming of the lakes threatens freshwater supplies and ecosystems, the scientists report in their study, published in the journal Geophysical Research Letters. They say their study is the largest of its kind and the first to combine satellite temperature data and long-term ground measurements.