CO2 rise may speed
up global warming
By Michael McCarthy, Environment Editor
11 October 2004
The rate at which global warming gases are accumulating in the atmosphere
has taken a sharp leap upwards, leading to fears that the devastating
effects of climate change may hit the world even sooner than has been
Atmospheric levels of carbon dioxide (CO2 ), the principal
greenhouse gas, have made a sudden jump that cannot be explained by any
corresponding jump in terrestrial emissions of CO2 from power stations and
motor vehicles - because there has been none.
Some scientists think instead that the abrupt speed-up may be
evidence of the long-feared climate change "feedback" mechanism,
by which global warming causes alterations to the earth's natural systems
and then, in turn, causes the warming to increase even more rapidly than
Such a development would mean the worldwide droughts,
agricultural failure, sea-level rise, increased weather turbulence and
flooding all predicted as consequences of climate change would arrive on
much shorter time-scales than present scenarios suggest, and the world
would have much less time to co-ordinate its response.
Only last month, Tony Blair expressed anxiety that global
warming's dire effects would arrive not just in his children's lifetime,
but in his own, and would "radically alter human existence".
fear as carbon levels soar
bewildered by sharp rise of CO2 in atmosphere for second year running
Paul Brown, environment correspondent
Monday October 11, 2004
An unexplained and unprecedented rise in carbon dioxide in the atmosphere
two years running has raised fears that the world may be on the brink of
runaway global warming.
Scientists are baffled why the quantity of the main
greenhouse gas has leapt in a two-year period and are concerned that the
Earth's natural systems are no longer able to absorb as much as in the
The findings will be discussed tomorrow by the government's
chief scientist, Dr David King, at the annual Greenpeace business lecture.
Measurements of CO2 in the atmosphere have been continuous
for almost 50 years at Mauna Loa Observatory, 12,000ft up a mountain in
Hawaii, regarded as far enough away from any carbon dioxide source to be a
reliable measuring point.
In recent decades CO2 increased on average by 1.5 parts per
million (ppm) a year because of the amount of oil, coal and gas burnt, but
has now jumped to more than 2 ppm in 2002 and 2003.
Above or below average rises in CO2 levels in the atmosphere
have been explained in the past by natural events.
When the Pacific warms up during El Niņo - a disruptive
weather pattern caused by weakening trade winds - the amount of carbon
dioxide rises dramatically because warm oceans emit CO2 rather than absorb
But scientists are puzzled because over the past two years,
when the increases have been 2.08 ppm and 2.54 ppm respectively, there has
been no El Niņo.
Charles Keeling, the man who began the observations in 1958
as a young climate scientist, is now 74 and still working in the field.
He said yesterday: "The rise in the annual rate to above two
parts per million for two consecutive years is a real phenomenon.
"It is possible that this is merely a reflection of
natural events like previous peaks in the rate, but it is also possible
that it is the beginning of a natural process unprecedented in the
Analysts stress that it is too early to draw any long-term
But the fear held by some scientists is that the greater than
normal rises in C02 emissions mean that instead of decades to bring global
warming under control we may have only a few years. At worst, the figures
could be the first sign of the breakdown in the Earth's natural systems
for absorbing the gas.
That would herald the so-called "runaway greenhouse
effect", where the planet's soaring temperature becomes impossible to
contain. As the ice caps melt, less sunlight is reflected back into space
from ice and snow, and bare rocks begin to absorb more heat. This is
One of the predictions made by climate scientists in the
Intergovernmental Panel on Climate Change is that as the Earth warms, the
absorption of carbon dioxide by vegetation - known as "carbon
sink" - is reduced.
Dr Keeling said since there was no sign of a dramatic
increase in the amount of fossil fuels being burnt in 2002 and 2003, the
rise "could be a weakening of the Earth's carbon sinks, associated
with the world warming, as part of a climate change feedback mechanism. It
is a cause for concern'.'
Tom Burke, visiting professor at Imperial College London, and
a former special adviser to the former Tory environment minister John
Gummer, warned: "We're watching the clock and the clock is beginning
to tick faster, like it seems to before a bomb goes off."
Peter Cox, head of the Carbon Cycle Group at the Met Office's
Hadley Centre for Climate Change, said the increase in carbon dioxide was
not uniform across the globe.
Measurements of CO2 levels in Australia and at the south pole
were slightly lower, he said, so it looked as though something unusual had
occurred in the northern hemisphere.
"My guess is that there were extra forest fires in the
northern hemisphere, and particularly a very hot summer in Europe,"
Dr Cox said. "This led to a die-back in vegetation and an increase in
release of carbon from the soil, rather than more growing plants taking
carbon out of the atmosphere, which is usually the case in summer."
Scientists are have dubbed the two-year CO2 rise the Mauna
Loa anomaly. Dr Cox said one of its most interesting aspects was that the
CO2 rises did not take place in El Niņo years. Previously the only
figures that climbed higher than 2 ppm were El Niņo years - 1973, 1988,
1994 and 1998.
The heatwave of last year that is now believed to have
claimed at least 30,000 lives across the world was so out of the ordinary
that many scientists believe it could only have been caused by global
But Dr Cox, like other scientists, is concerned that too much
might be read into two years' figures. "Five or six years on the trot
would be very difficult to explain," he said.
Dr Piers Forster, senior research fellow of the University of
Reading's Department of Meteorology, said: "If this is a rate change,
of course it will be very significant. It will be of enormous concern,
because it will imply that all our global warming predictions for the next
hundred years or so will have to be redone."