The Covid pandemic shutdowns in South Asia greatly reduced the concentration of short-lived cooling particles in the air, while the concentration of long-lived greenhouse gases was barely affected. Researchers were thus able to see how reduced emissions of air pollution leads to cleaner air but also stronger climate warming.
It is well known that emissions of sulfur and nitrogen oxides and other air pollutants lead to the formation of aerosols (particles) in the air that can offset, or mask, the full climate warming caused by greenhouse gases such as carbon dioxide and methane. But there has been a lack of knowledge about this ‘masking effect’. In order to determine the size, large-scale experiments involving huge regions would be required – this is infeasible.
The Covid pandemic became such a ‘natural’ experiment. In the spring of 2020, the activity of many industries and transportation worldwide decreased due to pandemic restrictions. This created a unique opportunity to study what happens to the climate if emissions of gases and aerosols are rapidly reduced.
Read more at Stockholm University
Photo: Measuring station Hanimaadhoo in the Maldives. Photo Credit: Joakim Romson