May 12, 2006
Climate change is
man-made, and difficult to slow
Average temperatures
could increase by as much as 6 C
JANE
GEORGE
Man-made pollution is driving
global warming, and the scale of the warming is now more intense than at any
time over the past 20,000 years, according to a draft report of the Intergovernmental
Panel on Climate Change.
The draft report says:
- Arctic sea ice has shrunk
by 2.7 per cent per decade since 1978 and by 7.4 per cent each decade during
the summer months: "the smallest extent of summer sea ice was observed
in 2005";
- Five of the six warmest
years have occurred in the past five years, with 2005 and 1998 being the two
warmest years on record;
- Global average sea levels
rose at a rate of about two mm a year between 1961 and 2003, and by an average
of more than three mm a year between 1993 and 2003;
- Melting glaciers and
polar ice sheets could cause sea levels to rise by up to 43 cm by 2100, and
the increase for the next 200 years is predicted to be nearly double that
figure;
- Mountain glaciers and
polar land ice have, in general, melted faster than they have formed over
the past 40 years;
- Permafrost temperatures
have increased, and the area covered by seasonally frozen ground has decreased
by about seven per cent over the past 50 years.
The draft report concludes
there is now overwhelming evidence to show that the global climate is changing
because of human activity.
And it says climate change
will continue for decades and perhaps centuries if man-made greenhouse gas emissions
can be reduced.
The draft report says concentrations
of carbon dioxide, methane and other greenhouse gases are at the highest for
at least 650,000 years.
It predicts that global
average temperatures will rise by between 2 C and 4.5 C by 2100 as a result
of the doubling of carbon dioxide levels caused by greenhouse gas emissions.
Average temperatures could
increase by 6 C as a result of "positive feedbacks" in the climate
resulting from the melting of sea ice, thawing permafrost and the acidification
of the oceans.
The draft report is the
fourth climate assessment by the IPCC since it was created in 1988. The report
was to be kept under wraps until the final version is ready for publication
next year.
However, a U.S. government
committee made a copy of the draft report available on the Internet to anyone
who made an e-mail request for a password to access the area on its web site,
and the draft report has surfaced since on many media and web sites.
The IPCC's Working Group
1, which examines scientific findings related to the physical cause of climate
change, drafted the document. The analyses of working groups II and III, outlining
consequences from the first group's findings and suggested solutions, have not
been released yet.
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