That’s an important paper and message: Leipzig researchers have found that large-scale deforestation has a greater warming effect on the climate than previously assumed. The cooling effect of cloud cover is reduced by almost half as a result.
Experts led by Hao Luo and Johannes Quaas from the Institute of Meteorology at the University of Leipzig demonstrated a reduction in clouds in these deforested areas by analyzing computer simulations and observations. Deforestation has a warming effect by releasing carbon dioxide, but at the same time forests are darker than the areas after deforestation. This leads to a cooling effect because less sunlight is absorbed. The new study was able to prove that the reduction of cloud cover reduces this cooling effect by almost half.
“We found that as a result of deforestation, low-lying clouds are decreasing globally, and in the tropics, high-lying clouds are also decreasing,” explains Luo. “Low-lying clouds have a cooling effect on the climate because they reflect a lot of sunlight,” adds Quaas. The scientists analyzed idealized deforestation simulations using climate models and reanalyses and, on this basis, provided insights into a local decrease in global low-lying clouds and tropical high-lying clouds as a result of large-scale deforestation.
“The reduced cloud cover can be explained by changes in the turbulent heat flow at the surface, which reduces buoyancy and moisture to varying degrees,” says Quaas, who also works at the German Center for Integrative Biodiversity Research Halle-Jena-Leipzig (iDiv). According to the researchers, the effects of the different meteorological processes in forests and cleared areas on clouds and the associated radiation balance have not yet been sufficiently investigated.
