The Final Proof:
Global Warming
Is Man-Made
By Steve Connor
21 February, 2005
The
Independent
Scientists have found the first unequivocal
link between man-made greenhouse gases and a dramatic heating of the
Earth's oceans. The researchers - many funded by the US government -
have seen what they describe as a "stunning" correlation between
a rise in ocean temperature over the past 40 years and pollution of
the atmosphere.
The study destroys
a central argument of global warming skeptics within the Bush administration
- that climate change could be a natural phenomenon. It should convince
George Bush to drop his objections to the Kyoto treaty on climate change,
the scientists say.
Tim Barnett, a marine
physicist at the Scripps Institution of Oceanography in San Diego and
a leading member of the team, said: "We've got a serious problem.
The debate is no longer: 'Is there a global warming signal?' The debate
now is what are we going to do about it?"
The findings are
crucial because much of the evidence of a warmer world has until now
been from air temperatures, but it is the oceans that are the driving
force behind the Earth's climate. Dr Barnett said: "Over the past
40 years there has been considerable warming of the planetary system
and approximately 90 per cent of that warming has gone directly into
the oceans."
He told the American
Association for the Advancement of Science in Washington: "We defined
a 'fingerprint' of ocean warming. Each of the oceans warmed differently
at different depths and constitutes a fingerprint which you can look
for. We had several computer simulations, for instance one for natural
variability: could the climate system just do this on its own? The answer
was no.
"We looked
at the possibility that solar changes or volcanic effects could have
caused the warming - not a chance. What just absolutely nailed it was
greenhouse warming."
America produces
a quarter of the world's greenhouse gases, yet under President Bush
it is one of the few developed nations not to have signed the Kyoto
treaty to limit emissions. The President's advisers have argued that
the science of global warming is full of uncertainties and change might
be a natural phenomenon.
Dr Barnett said
that position was untenable because it was now clear from the latest
study, which is yet to be published, that man-made greenhouse gases
had caused vast amounts of heat to be soaked up by the oceans. "It's
a good time for nations that are not part of Kyoto to re-evaluate their
positions and see if it would be to their advantage to join," he
said.
The study involved
scientists from the US Department of Energy, the Lawrence Livermore
National Laboratory in California and the US National Oceanic and Atmospheric
Administration, as well as the Met Office's Hadley Center.
They analyzed more
than 7 million recordings of ocean temperature from around the world,
along with about 2 million readings of sea salinity, and compared the
rise in temperatures at different depths to predictions made by two
computer simulations of global warming.
"Two models,
one from here and one from England, got the observed warming almost
exactly. In fact we were stunned by the degree of similarity,"
Dr Barnett said. "The models are right. So when a politician stands
up and says 'the uncertainty in all these simulations start to question
whether we can believe in these models', that argument is no longer
tenable." Typical ocean temperatures have increased since 1960
by between 0.5C and 1C, depending largely on depth. DR Barnett said:
"The real key is the amount of energy that has gone into the oceans.
If we could mine the energy that has gone in over the past 40 years
we could run the state of California for 200,000 years... It's come
from greenhouse warming."
Because the global
climate is largely driven by the heat locked up in the oceans, a rise
in sea temperatures could have devastating effects for many parts of
the world.
Ruth Curry, from
the Woods Hole Oceanographic Institution, said that warming could alter
important warm-water currents such as the Gulf Stream, as melting glaciers
poured massive volumes of fresh water into the North Atlantic. "These
changes are happening and they are expected to amplify. It's a certainty
that these changes will put serious strains on the ecosystems of the
planet," DR Curry said.
© 2005 Independent
News & Media (UK) Ltd