U East Anglia Researcher - "It Can't Be More Clear That Human Activity Is Responsible" For Warming

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Evidence has emerged that human activity, not natural phenomena, is directly responsible for heating up the polar ice caps. The news coincides with announcements earlier this week that the Arctic ice is now thinner than at any time since records began. "We knew the warming was happening there, especially in the Arctic," says Alexey Karpechko of the Climatic Research Unit at the University of East Anglia, UK, but pinning down the causes has not been possible until now.

Karpechko, head of the team which concluded that human activity is to blame, says their findings show at last that all continents of the world are being warmed through human activity. "The Antarctic was the only one where there was any doubt, but not any more," he says. "It's confirmation of expected results," says Gilles Sommeria, deputy secretary of the Intergovernmental Panel on Climate Change, the international alliance of scientists monitoring climate change. "It shows that human influence already observed in most regions is confirmed in Antarctica, where the data were scarcer."

To find out whether human activity was to blame at the poles, Karpechko and colleagues analysed temperature data collected at the poles over the past century. They ran the data through two sets of computerised climate models. Both sets factored in the effects of natural phenomena, such volcanic eruptions and solar sunspot cycles, but only one set factored in the consequences of human activities that can affect climate, such as rising levels of the greenhouse gas carbon dioxide and fluctuations in the amount of ozone in the stratosphere.

It was the models which included human factors that most closely matched the temperature profiles recorded at the poles. "For me, it can't be more clear that human activity is responsible," says Karpechko.

EDIT

http://environment.newscientist.com/channel/earth/climate-change/dn15085-humans-to-blame-for-polar-warming.html?feedId=climate-change_rss20