The 2013 Uttarakhand floods were most probably a consequence of “human-induced” climate change, a new report by the American Meteorological Society has suggested.
The extraordinary rainfall in Uttarakhand in June last year has found a place in a list of 16 extreme weather events that the report says were most likely a direct result of climate change.
This is probably the first time that any individual weather event in India has been attributed to climate change. Scientists are generally wary of blaming climate change for any single event, mainly because of the difficulty in establishing the causality, although there is a near unanimity that climate change is responsible for an increase in the frequency and intensity of extreme weather events.
The report ‘Explaining Extreme Events of 2013: From a Climate Perspective’, published in the September issue of Bulletin of the American Meteorological Society, does not directly say that climate change caused the floods but comes very close to that.
Based on statistical analysis, the paper on the Indian case says that the high rainfall in June 2013 (the entire month, not just four days of excessive rainfall in the middle of the month) was “at least a century-scale event”, meaning such precipitation can be expected only once in a century at the most. It then says that the analysis provides evidence that climate change can be held responsible for increased likelihood of such extreme events. “…our analyses of the observed and simulated June precipitation provide evidence that anthropogenic (human-induced) forcing of the climate system has increased the likelihood of such an event,” the report says. The Uttarakhand floods had caused a large-scale devastation in the region, killing thousands of people.
Several earlier studies have captured the increasing trend of extreme rainfall cases in India and sought to link it with climate change. But it is extremely difficult to establish whether any individual event is a result of seasonal weather variations or an effect of climate change.
The report acknowledges the limitations that science has in attributing individual events to climate change but says if wherever it is possible, such attributions need to be made.
“It is clear that extreme events capture the public’s attention… And, with or without the availability of a robust scientific analysis, the public often associates extreme events such as these with climate change. Scientific event attribution can help inform the public’s understanding of our changing environment… Observed events, such as those analysed in this report, demonstrate the vulnerabilities of societies to extremes of weather and climate. Enhancing scientific knowledge through attributions helps build environmental intelligence.”