Cloud cover decreasing due to large-scale deforestation, researchers say

Researchers from iDiv, the University of Leipzig and Sun Yat-sen University in China have discovered that large-scale deforestation has a greater global warming effect than previously thought. Their analysis of computer simulations and observations showed a decrease in cloud cover in these deforested areas.

Deforestation has a warming effect by releasing carbon dioxide, but at the same time, forests are darker than cleared areas. This effect causes cooling because less sunlight is absorbed. The new study shows that reducing cloud cover reduces this cooling effect by almost half. These new findings have just been published in the journal Nature Communications.

“We found a decrease in low clouds and high tropical clouds globally due to deforestation,” says Dr Hao Luo, lead author of the study and co-author of the study with his institute colleague Professor Johannes Quaas and Professor Yong Han from Sun Yat-sen University in China. Johannes Quaas adds: “Low clouds have a cooling effect on the climate because they reflect a lot of sunlight.”

The researchers analyzed idealized deforestation simulations using climate models and reanalyses, and based on this, provided insights into local decreases in global low-level clouds and tropical high-level clouds resulting from large-scale deforestation.

“The decrease in cloud cover can be explained by alterations in the turbulent heat flux at the surface, which reduce uplift and humidity to varying degrees,” says Professor Quaas, who also works at the German Center for Integrative Biodiversity Research (iDiv) in Halle-Jena-Leipzig.

According to the researchers, the impact of different meteorological processes in forests and deforested areas on clouds and the associated radiation budget has not yet been adequately studied. For example, researchers in meteorology and biodiversity science are currently investigating the role of forest biodiversity and its impact on clouds.