A new study has revealed that small lakes on Earth have expanded considerably over the last four decades – a worrying development, considering the amount of greenhouse gases freshwater reservoirs emit.
Between 1984 and 2019, global lake surfaces increased in size by more than 46,000 square kilometers (17,761 square miles), researchers say. That’s slightly more than the area covered by Denmark.
Carbon dioxide, methane, nitrous oxide, and other gasses are constantly produced from lakes, because of the bacteria and fungi feeding at the bottom of the water, snacking on dead plants and animals that have drifted down to the lake floor.
In total, this lake spread equates to an annual increase of carbon emissions in the region of 4.8 teragrams (or trillion grams) of CO2 – which to continue the country comparisons equals the increase in CO2 emitted by the whole of the UK in 2012.
“There have been major and rapid changes with lakes in recent decades that affect greenhouse gas accounts, as well as ecosystems and access to water resources,” says terrestrial ecologist Jing Tang, from the University of Copenhagen in Denmark.
“Among other things, our newfound knowledge of the extent and dynamics of lakes allows us to better calculate their potential carbon emissions.” [Continue reading…]