A man carrying his belongings wades through a flooded street in Nonthaburi province, on the outskirts of Bangkok November 18, 2011. (c) Reuters
In the year 2011 alone, the US faced 14 extreme weather events, while Japan registered record rainfalls and the Yangtze river basin in China suffered a record drought. The year 2010 saw Russia in the midst of its hottest summer in centuries, while Pakistan and Australia received record-breaking amounts of rain, highly atypical for the region. As for Europe, 2003 was the hottest summer in 500 years. A new report published in the journal Nature Climate Change suggests that it’s very likely that all these climate effects are human-induced.
“It is very likely that several of the unprecedented extremes of the past decade would not have occurred without anthropogenic global warming,” said the study.
Besides unusual climate events or catastrophes, the last decade was the hottest for at least a millennium, while 2011 saw global record temperature levels. The scientists at Germany’s Potsdam Institute for Climate Research who were involved in the research claim that these types of extreme weather are not normal by any means, representing the effect of human action. They used physics, statistical analysis and computer simulations to link extreme rainfall and heatwaves to global warming. The link between warming and storms was less clear.
“The question is whether these weather extremes are coincidental or a result of climate change,” says Dim Coumou.
“Global warming can generally not be proven to cause individual extreme events – but in the sum of events the link to climate change becomes clear.”
Basic physics explains why global warming might induce extreme weather as a result of a warmer atmosphere, for instance warm air can hold more moisture until it rains out. Also, clear statistical trends can be found in temperature and precipitation data, while detailed computer simulations also confirm a link between warming and both temperature and precipitation. However, scientists cannot attribute a particular event to human-caused climate change.
A recent study published in the journal Nature Geoscience, found that the Earth is warming at a faster rate than previously thought, leading at the current rate to a temperature increase between 1.4°C and 3°C in 2050, compared to the global average measured between 1961 and 1990. This would mean even more extreme weather in years to come.
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