New research released today must surely convince the
Government of the urgent need to tackle climate change,
Greenpeace says.
The research, involving New Zealand scientists, suggested a
large proportion of Antarctic ice was set to melt over the
next 100 years.
It said the entire West Antarctic ice sheet was likely to
melt within 1000 years.
The meltwaters, and thermal expansion as oceans warmed, were
likely to trigger sea level rises measured in metres, rather
than the 59cm currently predicted by many climate scientists.
When similar melting already under way on the Greenland ice
shelf was taken in to account, average sea levels were likely
to be 12 metres higher than today -- over a long period --
with 5m of that rise coming from West Antarctica.
Greenpeace senior climate campaigner Simon Boxer, commenting
on research published today in Nature magazine, said the
Antarctic had experienced an extremely rapid temperature rise
over the last 50 years, caused by manmade climate change.
"Ice levels in Antarctica have not been this low for a
millennium," he said.
"Combine that with the incredible loss of ice in the Arctic
and youve got some very stark reminders that climate change
is occurring and is worse than originally thought."
The latest research is based on analysis of a 1280m-long core
taken from the sea floor under the Ross Ice Shelf by New
Zealand drillers working for the $30 million Antarctic
Geological Drilling (Andrill) research programme.
A team of researchers led by Professor Tim Naish, director of
Victoria University's Antarctic research centre, has shown
that when atmospheric carbon dioxide concentrations reached
400 parts per million (ppm) -- around 4 million years ago --
the globe warmed up enough to enhance an existing effect
caused by variations in the Earth's tilt towards the Sun.
This was enough to trigger sheet fluctuations in the size of
the West Antarctic ice sheet.
Now the carbon dioxide concentration in the atmosphere is
again approaching 400 ppm.
Even carbon dioxide concentrations in the atmosphere only
slightly higher than today could affect the stability of the
West Antarctic ice sheet, according to the 50 researchers,
who come from the United States, Italy and Germany, as well
as New Zealand.
Other recent studies showed melting had already begun.
A related study led by Dr David Pollard of Pennsylvania State
University in the US, also published today in Nature, used a
computer model of the ice sheets to show that when the West
Antarctic ice sheet collapsed, the margin of the East
Antarctic Ice Sheet also melted and the meltwater from both
lifted sea levels an average of 7m.
Publication of the research followed a climate congress in
Copenhagen, Denmark, last week, where more than 2500 climate
scientists and researchers issued an urgent plea to political
leaders to get on with addressing climate change.
"The science is so stark and ahead of predictions, that
developed countries like New Zealand must now adopt emission
reduction targets of at least 40 percent below 1990 levels by
2020, if the world is to avoid catastrophic climate change,"
said Mr Boxer.
Greenpeace is calling on the Government to adopt a binding
emission reduction target of 40 percent by 2020 at UN climate
talks in Copenhagen in December.
