The hole in the Arctic ozone layer influences seasonal temperature and precipitation patterns in the northern hemisphere. According to ETH researchers, it would be possible to improve weather and climate models by integrating this information.
The ozone layer is destroyed both above Antarctica and, to a lesser extent, above the Arctic. The density of the layer varies during the year: in the Arctic it always reaches its minimum value in the spring and then forms the so-called hole in the ozone layer.
The shrinking of the ozone layer is dangerous, because without this protective layer, more UV rays reach the Earth. This can lead to health problems like skin cancer.
In addition, it was already known for Antarctica that the decline in ozone had a large-scale impact on the climatic conditions of the southern hemisphere. Until now, it was not known whether this also applied to the hole in the Arctic ozone layer.
For the study published in the specialist journal ‘Nature Geoscience’, researchers at ETH Zurich analyzed data from the past four decades to investigate the influence of ozone depletion on the climate of northern hemisphere. They were gathered around the environmental scientist Marina Friedel.
The polar vortex collapses later
As a result of the study, the years during which the ozone layer was significantly depleted in the spring experienced, a few weeks later, warmer and drier conditions in southern Europe and Eurasia, as well as during periods heavy rainfall in northern Europe.
Computer models suggest that deeper ozone depletion is delaying the collapse of the so-called polar vortex in the spring. The polar vortex is an area of low pressure located in the stratosphere, at an altitude of 15 to 50 kilometers, which forms each autumn over the Arctic and whose lifespan is variable. According to the researchers, the prolonged existence of the polar vortex causes the observed temperature and precipitation anomalies.
The ozone layer is recovering, but…
Many current meteorological and climate models do not take into account the annual variations of stratospheric ozone, or do so in a very simplified way. The researchers assume that it would be possible to improve the forecasting ability of the models thanks to more precise information on the state of the ozone layer. Future studies should show what the potential for better predictions is.
Since the global ban on chlorofluorocarbons (CFCs), which destroy the ozone layer, it is slowly being rebuilt over Antarctica and the Arctic. Nevertheless, according to the researchers, there will still be strong episodes of ozone destruction in the future, which will continue to have an impact on the global climate.
/ATS
