Climate change causes extreme weather

Potsdam is home to one of the world’s leading climate research institutes, the PIK.

Human-triggered climate change has been the cause of a lot of the recent extreme weather across the globe, according to a new scientific study. A team from the Potsdam Institute for Climate Impact Research (PIK) says it has found a physical cause common to events such as the 2011 heat waves in the USA, the 2010 Russian heat wave or the floods in Pakistan in the same year. The scientists, whose study is published in the US journal Proceedings of the National Academy of Sciences this week, say climate change is affecting the movement of air around the northern hemisphere, resulting in extreme conditions. Lead author Vladimir Petoukov says: “An important part of the global air movement in the mid-latitudes of the earth normally takes the form of waves travelling around the planet, oscillating between the tropical and the Arctic regions. When they travel upwards, these waves suck warm air from the tropics to Europe, Russia, or the USA; when they dip downwards, they do the same with cold air from the Arctic. We found that during several recent extreme weather events, these waves virtually froze and remained unchanged for weeks. Instead of bringing in cool air after warm air, the heat just stays. ”

The mechanism is a complex one and the report is not easy reading. I can recommend a summary produced by Alex Kirby for the “Climate News Network“.

PIK’s director Hans Joachim Schellnhuber, a co-author of the study, describes it as a breakthrough, but stresses there are other factors involved in extreme weather events as well as climate change. However, he and his colleagues say the physical process they have identified helps to explain the increasing number of weather extremes and provides a mechanism to explain a link between climate change and extreme weather.