The emissions of carbon dioxide (CO2) and methane (CH4) - the most potent greenhouse gases - into the atmosphere from African lakes are reassessed in a study undertaken by the Laboratory of Chemical Oceanography (FOCUS research unit / Faculty of Science). While it was previously assumed that these lakes were significant CO2 sources, it has since been discovered that they really emit very little CO2 but a lot of methane, adding to the emissions burden. The study is published in Science Advances.
One of the keys to predict climate change is to predict how greenhouse gas (GHG) emissions from our planet's natural ecosystems might change. But to do this, it is important to be able to estimate them as accurately as possible and to understand the underlying mechanisms. There are about 1.5 million lakes on Earth. Unlike the oceans, they play an important role in the emission of greenhouse gases. Recognition of the important role of continental waters as emitters of carbon dioxide (CO2 ) and methane (CH4 ) - the two main GHGs - came rather late. It was not until in the mid-1990s that they began to be studied and are therefore relatively little sampled. “This is problematic, explains Alberto Borges, FNRS researcher at the Laboratory of Chemical Oceanography at ULiège, "because spatial heterogeneity is very important, both within a single lake or river and between different systems. If the heterogeneity is very high, very large amounts of data are required to obtain a robust estimate of GHG emissions. There are almost two million lakes on Earth.”
Until now, researchers have only had data on North American and Scandinavian (boreal) lakes and very little on tropical lakes and none on African lakes. These values were extrapolated to all lakes worldwide, including tropical lakes. However, these lakes do not "behave" in the same way in terms of GHG sequestration and emissions. A study conducted over ten years by researchers from the ULiège Chemical Oceanography Laboratory has shown that the data collected for North American and Scandinavian lakes does not apply to African lakes.
Read more at University of Liege
Photo Credit: SimonDAllen via Pixabay