A group of scientists have found evidence that suggests the recent wave of extreme weather events linked to global warming.
The debate on whether current extreme weather conditions can be held responsible for global warming has been raging for years. Recently, a group of scientists have found a mechanism in the atmosphere that suggests that the recent spate of extreme weather events can indeed be blamed for global warming.
Global warming usually takes place when waves of air oscillate between the Earth's tropical and Arctic regions, alternately pulling warm air up from the tropics to northern climates, then bringing cold air down from the Arctic. However, due to uneven global warming, these waves are getting stuck.
"What we found is that during several recent extreme weather events these planetary waves almost freeze in their tracks for weeks. So instead of bringing in cool air after having brought warm air in before, the heat just stays," said Vladimir Petoukhov of the Potsdam Institute for Climate Impact Research (PIK), lead author of a paper to be published in the Proceedings of the National Academy of Sciences.
According to the mechanism found, with the increase in global temperatures, the Arctic is warming at a rate faster than other parts of the Northern hemisphere. Due to this, there is a vast temperature difference between Arctic air and more southerly air which in turn is disrupting the airflow in these regions. Also, global land mass is concentrated in the Northern hemisphere and land masses tend to warm and cool more quickly than oceans do.
"These two factors are crucial for the mechanism we detected," Petoukhov said. "They result in an unnatural pattern of the mid-latitude air flow, so that for extended periods the slow synoptic waves get trapped."
"Our dynamical analysis helps to explain the increasing number of novel weather extremes," said coauthor and PIK director Hans Joachim Schellnhuber. "It complements previous research that already linked such phenomena to climate change, but did not yet identify a mechanism behind it."
