King Carl XVI Gustaf and Ray Pierrehumbert. Photo: Eva Dalin
King Carl XVI Gustaf and Ray Pierrehumbert. Photo: Eva Dalin

American Raymond (Ray) Pierrehumbert is one of the most distinguished researchers in the climate area. He is also a frequent participant in the debate about what should be done to reduce emissions of greenhouse gases. For more than two decades, Ray Pierrehumbert had collaboration with climate researchers at Stockholm University and also worked here for several periods. During this school year, he is one of two holders of the King's guest professor in environmental science at the Department of Meteorology, Stockholm University.

Lecture before King Carl XVI Gustaf

On 11 February, a public lecture by Ray Pierrehumbert in the Aula Magna was organised. Among the approximately five hundred guests, King Carl XVI Gustaf was an interested listener. After the lecture there was a panel discussion. The theme of the lecture was how Sweden can lead efforts to reduce emissions of carbon dioxide. And here Ray Pierrehumbert has high hopes: “If everyone would be like Sweden, then the world would be a better place”.

He then took the audience on a journey through the carbon cycle, from when the universe was created in a big bang and spread the coal, and what it meant when photosynthesis and the natural carbon cycle arose, to how humans in the last century has affected the carbon cycle.

Important figure to keep track of

“There is one figure we need to keep track of and that is the total amount of coal that is stored in the atmosphere. When the total amount of coal that has been burnt and transferred into the atmosphere amounts to one trillion tonnes then the global temperature will have risen by two degrees. So far we have transferred half a trillion tonnes of carbon to the atmosphere”, said Ray Pierrehumbert.

In the last one hundred years, the levels of carbon dioxide in the atmosphere has increased dramatically, and it is because of human influence. According to Ray Pierrehumbert, we have entered a new geological period – Anthropocene – created by human influence.

“In efforts to reduce emissions of carbon into the atmosphere, Sweden has an important role to play,” he continued. “Our emissions are small compared to other states but we can serve as a model, mainly by showing that climate measures can be combined with economic growth”.

Panel discussion with Environment Minister Åsa RomsonKing Carl XVI Gustaf and Ray Pierrehumbert. Photo: Eva Dalin

King Carl XVI Gustaf and Ray Pierrehumbert. Photo: Eva Dalin

Ray Pierrehumbert was also one of the participants in the panel discussion that followed after the lecture. It was also attended by Per Krusell, professor of economics at Stockholm University, Karin Bäckstrand, professor of social science research at the university, and climate and environment minister Åsa Romson who also has a background at Stockholm University where she holds a doctorate in environmental law. Åsa Romson emphasized the importance of increased research into climate change and its effects, also with contributions from fields other than natural science.

Need for international carbon tax

Per Krusell highlighted the importance of economic instruments in climate policy. Taxes and charges on emissions can be very important and he advocated an international tax on carbon dioxide emissions.
Karin Bäckstrand conducts research on the international climate negotiations in progress. She highlighted the importance of voluntary organisations to examine what happens in the negotiations but also as a way to bring forward public opinion.

After the panel it was possible to ask questions. Issues discussed were questions such as fairness on how much carbon dioxide different states and individuals release, fusion energy, and what investments should be made in different communication types. There wasn’t time to discuss all questions, but Ray Pierrehumbert urged the audience to get in touch with him to discuss the issues.

In the autumn Ray Pierrehumbert assumes the Halley professure in Physics at Oxford.

Learn more about Ray Pierrehumbert: Climate Professor aiming for zero emissions

Watch video of the lecture