Originally posted on sciy.org by Ron Anastasia on Sun 21 Jan 2007 03:07 PM PST
Online edition of India's National Newspaper
Saturday, Jan 20, 2007
ePaper
Rise in carbon levels fuels fears of runaway warming
David Adam
| Scientists warn the earth may be absorbing less gas. |
Steam pours into the air from cooling towers at a coal-fired power station in England on January 10. The European Commission has said the EU must reduce greenhouse gas emissions by at least 20 per cent below 1990 levels by 2020 to limit global warming.
CARBON DIOXIDE is accumulating in the atmosphere much faster than scientists expected, raising fears that humankind may have less time to tackle climate change than previously thought.
New figures from dozens of measuring stations across the world reveal that concentrations of CO2, the main greenhouse gas, rose at record levels during 2006 — the fourth year in the last five to show a sharp increase.
At its most far-reaching, the finding could indicate that global temperatures are making forests, soils, and oceans less able to absorb CO2 — a shift that would make it harder to tackle global warming.
David Hofmann of the U.S. National Oceanic and Atmospheric Administration (NOAA), which published the figures, said: "Over this last decade the growth rates in carbon dioxide have been higher. I don't think we can plausibly say what's causing it. It's something we're going to look at closely."
Peter Cox, a climate change expert at Exeter University in the U.K., said: "The concern is that climate change itself will affect the ability of the land to absorb our emissions." At the moment around half of human carbon emissions are reabsorbed by nature but the fear among scientists is that increasing temperatures will work to reduce this effect.
Professor Cox added: "It means our emissions would have a progressively bigger impact on climate change because more of them will remain in the air. It accelerates the rate of change so we get it sooner and we get it harder."
CO2 concentration in the atmosphere is measured in parts per million (ppm). From 1970 to 2000 that concentration rose by about 1.5ppm each year, as human activities sent more of the gas into the atmosphere. According to the latest figures, last year saw a rise of 2.6ppm. And 2006 was not alone. A series of similar jumps in recent years means the carbon dioxide level has risen by an average 2.2ppm each year since 2001.
Above average annual rises in carbon dioxide levels have been explained by natural events such as the El Nino weather pattern, centred on the Pacific Ocean. But the last El Nino was in 1998, when it resulted in a record annual increase in carbon dioxide of 2.9ppm. If the current trend continues, this year's predicted El Nino could see the annual rise in carbon dioxide pass the 3ppm level for the first time.
Professor Cox said that an increase in forest fires, heat waves across Europe, and the Amazon drought of 2005 could have helped to drive up CO2 levels. He admitted that "the jury is still out" on whether the recent spike is evidence of a significant change, although some computer models predict that the earth will start to absorb less carbon dioxide sometime this decade.
"Over the past few years carbon dioxide has been going up faster than we would expect based on the rate that emissions are increasing," Professor Cox said.
Figures presented to a recent United Nations climate conference in Nairobi showed that carbon dioxide emissions produced by the worldwide burning of fossil fuels increased 3.2 per cent from 2000 to 2005.
From 1990 to 1999 the emissions increase was 0.8 per cent. But other experts think rising emissions could yet account for the anomaly.
The Intergovernmental Panel on Climate Change is expected to announce more robust emissions data when it reports early next month. —
© Guardian Newspapers Limited 2007
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