Credit: Katarina Werneburg
They studied the extent to which cirrus clouds caused by aircraft occurred during the global hard lockdown between March and May 2020, and compared the values with those during the same period in previous years. The study was led by Johannes Quaas, Professor of Theoretical Meteorology at Leipzig University, and has now been published in the renowned journal
Environmental Research Letters .
Cirrus clouds, known for their high, wispy strands, contribute to warming the climate. When cirrus clouds occur naturally, large ice crystals form at an altitude of about 36 kilometres, in turn reflecting sunlight back into space - albeit to a small extent. However, they also prevent radiated heat from escaping the atmosphere, and thus have a net heating effect. This is the dominant effect in cirrus clouds.