Researchers at ETH Zurich prove that the depletion of the Arctic ozone layer in the spring is causing extreme weather throughout the northern hemisphere. Most places will be moderately warm and dry – or very wet.
Most people are familiar with the ozone layer over Antarctica. Little is known that the protective ozone layer in the stratosphere is also being destroyed periodically over the Arctic, and the ozone layer is being reduced. The last time this happened was in the spring months of 2011 and 2020.
Following these two events, meteorologists found that climate change was widespread throughout the northern hemisphere. It was hot and dry in those springs in Central and Northern Europe, Russia, and Siberia. In contrast, wet conditions were prevalent in the tropics. These climate problems were highlighted, especially in 2020. In Switzerland, too, it was warm and dry that spring.
Whether there is a causal link between ozone depletion in the stratosphere and observed climates is controversial in climate research. The polar vortex in the stratosphere, which forms in winter and disperses in the spring, also plays a role. Scientists who have studied this phenomenon have come up with incredible results and various conclusions.
Now medical student Marina Friedel and SNSF Ambizione Partner Gabriel Chiodo from the Thomas Peter team, Professor of Atmospheric Chemistry in ETH Zurich, in partnership with Princeton University and other universities, are shedding light on this issue.
To identify potential causes, researchers are mimicking this trend by combining ozone depletion into two different climate models. Many climate models consider only the physical features, not the variation in stratospheric ozone levels, partly because this may require additional computing power.
However, new statistics make it clear that the cause of climate change in the northern hemisphere in 2011 and 2020 is primarily ozone depletion in the Arctic. The researchers’ simulations with the two models were consistent with observational data from two years and eight other events used for comparative purposes. However, the observations would not have been reproduced if ozone depletion had been “turned off” in the models.
“From a scientific point of view, what really surprised us was that the models we used in the simulation were very different, but gave the same result,” said co-author Gabriel Chiodo, SNSF Ambizione Fellow at the Institute for Atmosphere and Climate.