Scientists link global warming with extreme weather

February 26, 2013

Scientists link global warming with extreme weather

Extreme weather may be related to climate change, according to scientists.

A study conducted by German scientists has revealed that warming caused by an increase in greenhouse gases may be behind a series of extreme weather events occurring across the globe the past few years.

The paper, published in Proceedings of the National Academy of Sciences, explains that the air waves move warm and cold air from the tropics to the Arctic stopping in Europe, the U.S., and more on the way. The research team from the Potsdam Institute for Climate Impact Research found the greenhouse gases often ran off course, causing giant air waves to be trapped in the atmosphere where they may have resulted in weather conditions aligned with heatwaves in 2011 and floods in Pakistan in 2010.

“During several recent extreme weather events these planetary waves almost freeze in their tracks for weeks,” Vladimir Petoukhov, the lead author of the research paper, said in an email statement. “So instead of bringing in cool air after having brought warm air in before, the heat just stays.”

Temperature differences are little more than moving air weaves. According to the Potsdam Institute research team, the air waves are trapped as more greenhouse gases are pumped into the atmosphere, disrupting crucial temperature differences. The researchers said the trapped air waves cause the Arctic to become hotter and Europe to become cooler, leading to more extreme climate shifts. In addition, continents heat and cool more rapidly than large bodies of water, the scientists say, and these two factors result in an unnatural pattern of the mid-latitude air flow. In ecosystems ill-equipped to handle the changes, the shift could lead to more disruptive climate behavior, say scientists.

“Our dynamic analysis helps to explain the increasing number of novel weather extremes,” said Hans Joachim Schellnhuber, who co-wrote the paper for the study. “It complements previous research that already linked such phenomena to climate change, but did not yet identify a mechanism behind it.”

While the study is the first to connect a series of extreme weather events with the aforementioned phenomenon, Schellnhuber cautioned that the 32-year period used in the study is too short for definitive conclusions. Still, a number of recent studies, including a series released by the U.S. space agency NASA, point to shifts in local climates around the world, which seem to indicate global warming remains a concern. According to a July report, NASA satellite data suggests that at one time or another 97 percent of the ice sheet that covers Greenland had thawed due to the persistence of a warm air mass over that land mass. Meanwhile, globally, 2012 was one of the warmest years on record, according to separate reports from NOAA and NASA released just this week.

This new study comes only weeks after President Barack Obama announced that climate change is a top priority of his second term as president of the United States. In his State of the Union address on February 12, President Obama said that in the wake of Hurricane Sandy, climate change will be a main part of his political agenda. In the speech, he said extreme weather events such as heat waves, droughts, wildfires, and floods “are now more frequent and intense.”

It remains unclear whether the result of the study will increase pressure on lawmakers around the world. Nearly 200 governments have vowed to work out by the end of 2015 a deal to combat rising global greenhouse gas emissions that will enter into force from 2020. A series of international meetings have yet to produce a successor to the Kyoto Protocol, which is widely seen as the most effective climate agreement to date.


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