The increasing frequency of extreme weather events has had meteorologists scratching their heads for a long time, unsure whether they could be firmly attributed to man-made climate change or not. Now, a study by a global team of scientists suggests that we can be squarely blamed in many cases.
The study, which is to be published soon in the Bulletin of the American Meteorological Society, attempts to decipher climate data and establish which extreme weather events are a result of man-made climate change. The results are interesting.
For instance, they claim that global warming made the severe heat in Texas last year 20 times as likely as it would have been in the 1960s. Elsewhere, they suggest that the incredibly warm temperatures in Britain last November were 62 times as likely because of global warming. But not every event is deemed a result of man-made climate change: last year's devastating floods in Thailand, for example, weren't. Instead, in that case, they suggest that rapid development in parts of Thailand is to blame.
The findings, of course, are bound to be controversial — especially when you consider the pace at which the research has been carried out. Usually studies which link climate change to weather events take years to publish, as the process of unpicking signal from noise in weather data is extremely difficult. In this case, a global team of scientists has managed to study six events from 2011 and publish the results in six months. Philip W. Mote, director of the Climate Change Research Institute at Oregon State University, explains to the New York Times:
"This is hot new science. It's controversial. People are trying different methods of figuring out how much the odds may have shifted because of what we have put into the atmosphere."
No doubt it will remain controversial, too. But it's hard to argue with some of their broader conclusions, which sound common-sensical but are now backed by some data: that heat waves are probably being worsened by global warming, and that an intensification of the water cycle results in increase in both droughts and heavy downpours.
What will prompt most speculation as to the validity of these results are the precise numbers which the scientists have allocated to the events — and certainly much more research is required before the evidence is entirely convincing. But in the meantime, the finding serves as a stark reminder that our planet does react to the way we treat it. [Bulletin of the American Meteorological Society, New York Times]
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