Study:Warming at Both Poles Definiteily Human-Caused

Study:Warming at Both Poles Definiteily Human-Caused

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/7700387.stm

Published: 2008/10/30 18:24:39 GMT © BBC MMVIII
Polar warming ’caused by humans’
By Pallab Ghosh, Science correspondent, BBC News

The rise in temperatures at Earth’s poles has for the first time been   attributed
directly to human activities, according to a study.

The work, by an international team, is published in Nature Geoscience   journal.

In 2007, the UN’s climate change body presented strong scientific evidence the rise
in average global temperature is mostly due to human activities.

This contradicted ideas that it was not a result of natural processes such as an
increase in the Sun’s intensity.

At the time, there was not sufficient evidence to say this for sure about the Arctic
and Antarctic.

“We really can’t claim anymore that it’s natural variations that are driving these
very large changes.”
Peter Stott, Met Office

Now that gap in research has been plugged, according to scientists who   carried out
a detailed analysis of temperature variations at both poles. Their study indicates
that humans have indeed contributed to warming in both regions.

Researchers expected this result for the Arctic-because of the recent sharp increase
in the melting of sea ice in the summer in the region-but temperature variations in
the Antarctic have until now been harder to interpret.

Today’s study, according to the researchers, suggests for the first time that
there’s a discernable human influence on both the Arctic and   Antarctica.

Best fit

The research team took the temperature changes over the polar regions of the Earth
and compared them with two sets of climate models.

One set assumed that there had been no human influence the other set   assumed there
had.

The best fit was with models that assumed that human activities
including the burning of fossil fuels and depletion of ozone had played a part.

According to one of the researchers involved with the study, Peter Stott, head of
climate monitoring and attribution at the Met Office, formally showing that the
Antarctic was being influenced by human activities was the key development

“In the recent IPCC report for example,” he said, “it wasn’t possible to make a
statement about the Antarctic because such a study had not been done at that point.

“But nevertheless when you do that you see a clear human fingerprint in the observed
data. We really can’t claim anymore that it’s natural variations that are driving
these very large changes that we are seeing in our in the climate system.”

Professor Phil Jones, director of the Climate Research Unit at the University of
East Anglia, said: “Our study is certainly closing a couple of gaps in the last IPCC
report.

“But I still think that a number of people, including some politicians, are
reluctant to accept the evidence or to do anything about it until we specifically
come down to saying that one particular event was caused by humans like a serious
flood somewhere or even a heatwave.

“Until we get down to smaller scale events in both time and space I still think
there will be people doubting the evidence.”

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