There is no doubt that extreme weather events such as superstorm Sandy that devastated New York are occurring more frequently because of climate change. It has also forced 4,000 species to alter where and how they live. More evidence is needed, however, to prove that our warming climate is being caused by human activity.
A session at the AAAS meeting specifically asked whether Sandy occurred because of climate change. It was impossible to make such a claim, but there is no doubt that we can expect to see more Sandy-like storms because of global warming, said Prof Donald Wuebbles of the University of Illinois.
Severe weather – from droughts to tornadoes, hurricanes to snow storms – have cost the US a collective $60 billion over the past two years alone, he said. There was no longer any scientific debate about whether climate was changing, the evidence is there to see. Only the cause has yet to be proven.
We were now 20 times more likely to have severe hurricanes and the most powerful storms are now 45 per cent more likely to occur in central US and 75 per cent more likely in the northeast than they were in the past he said. “The increased tendency in the US to have severe weather is expected to get worse in the future,” he said yesterday.
The impact on species is significant, said Prof Camille Parmesan of the University of Texas, Austin.
Researchers have catalogued 4,000 species that are in the process of adjusting to accommodate a warming climate. Half of these have changed where they live, often moving north or higher up to find lower temperatures. Two-thirds of the total have also changed how they live, changing their established breeding patterns, time of emergence or feeding.