Claudia Mohr Foto Markus Marcetic © Knut och Alice Wallenbergs Stiftelse Kungl. Vetenskapsakademien
Claudia Mohr. Foto: Markus Marcetic © Knut och Alice Wallenbergs Stiftelse Kungl. Vetenskapsakademien


The clouds that float through the sky are decisive for our climate. They are part of the water cycle and release rain to fall on the ground. Clouds can prevent the Earth’s heat from radiating out into space, but can also reflect the sun’s rays so they never reach the Earth’s surface.

“As an atmospheric scientist with a special interest in aerosol particles, clouds become somewhat naturally a topic: We know that aerosol particles influence the climate by changing cloud properties. These interactions of aerosol particles and clouds are one of the least understood processes in the climate system. I am therefore hoping that with new and advanced instrumentation I can contribute to increasing our understanding of how aerosol particles, especially from man-made sources, influence clouds, and thus the climate.”

Understanding how clouds are formed is important for predictions of climate trends in various parts of the world. There is, however, limited knowledge of how particles from human emissions affect clouds. Using innovative laboratory experiments, Claudia Mohr at the Department of Environmental Science and Analytical Chemistry, Stockholm University, will study how fine organic particles, aerosols, are formed, as well as how aerosols change in the atmosphere and how water condenses around them to make cloud droplets.

“There are still large uncertainties in our estimates of future climate. I am hoping that with my research I can contribute an additional piece to the puzzle of how we as humans change the climate.”

One important aim is understanding how humidity and temperature affect the process. She will also observe how cloud forms at high altitude on Åreskutan (1250 meters) in Sweden and on Mount Chacaltaya (5240 meters) in Bolivia. 

“This funding is an incredible opportunity for me to convert my research ideas into research activities. I can now acquire the necessary instrumentation and personnel to start looking into some of the important open questions related to climate change. I am an experimental scientist and use advanced instrumentation that needs a lot of resources, both in terms of money and personnel. I am beyond excited that the Wallenberg Academy Fellows funding now gives me the freedom to plan and execute my research without having to worry about the financial aspect.”