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co2_record_high_levels_in_the_atmosphere.htm

Global monthly mean co2  Carbon dioxide  years 2004 to 2009.

Dashed red line represents monthly mean values centered on middle of each month

Graph: NOAA
Dashed red line represents monthly mean values centered on middle of each month
Graph: NOAA
World CO2 levels at record high, scientists warn

David Adam
Monday May 12 2008
The concentration of carbon dioxide in the atmosphere has reached a record high, according to new figures that renew fears that climate change could begin to slide out of control.
Scientists at the Mauna Loa observatory in Hawaii say that CO2 levels in the atmosphere now stand at 387 parts per million (ppm), up almost 40% since the industrial revolution and the highest for at least the last 650,000 years.
The figures, published by the US National Oceanic and Atmospheric Administration (NOAA) on its website, also confirm that carbon dioxide, the chief greenhouse gas, is accumulating in the atmosphere faster than expected.
The annual mean growth rate for 2007 was 2.14ppm – the fourth year in the past six to see an annual rise greater than 2ppm.
From 1970 to 2000, the concentration rose by about 1.5ppm each year, but since 2000 the annual rise has leapt to an average 2.1ppm.
Scientists say the shift could indicate that the Earth is losing its natural ability to soak up billions of tons of carbon each year.
Climate models assume that about half our future emissions will be re-absorbed by forests and oceans, but the new figures confirm this may be too optimistic.
If more of our carbon pollution stays in the atmosphere, it means emissions will have to be cut by more than currently projected to prevent dangerous levels of global warming.
Martin Parry, co-chair of the Intergovernmental Panel on Climate Change's working group on impacts, said:
Despite all the talk, the situation is getting worse.
Levels of greenhouse gases continue to rise in the atmosphere and the rate of that rise is accelerating.
We are already seeing the impacts of climate change and the scale of those impacts will also accelerate, until we decide to do something about it.
Guardian Unlimited © Guardian Newspapers Limited 2008
 
Global growth in carbon emissions is 'out of control'
The growth in global emissions of carbon dioxide from fossil fuels over the past five years was four times greater than for the preceding 10 years, according to a study that exposes critical flaws in the attempts to avert damaging climate change.
By Steve Connor Science Editor
Published: 11 November 2006
Data on carbon dioxide emissions shows that the global growth rate was 3.2 per cent in the five years to 2005 compared with 0.8 per cent from 1990 to 1999, despite efforts to reduce carbon pollution through the Kyoto agreement.
Much of the increase is probably due to the expansion of the Chinese economy, which has relied heavily on burning coal and other fossil fuels for its energy.
Dr Mike Raupach, chair of the Global Carbon Project, an international collaboration of researchers who compiled the latest figures, warned yesterday that emissions were spiralling out of control.
Costa Rica to plant seven million trees in 2008
"This is a very worrying sign.   It indicates that recent efforts to reduce emissions have had virtually no impact on emissions growth and that effective caps are urgently needed," he said.
Current levels of carbon dioxide in the atmosphere are 380 parts per million (ppm), about 100ppm higher than before the Industrial Revolution 200 years ago.
Some computer models predict damaging and irreversible climate change if carbon dioxide levels rise above 450ppm or 500 ppm.
The rate of increase of emissions suggests it may soon be impossible to avoid some of the worst-case scenarios, said Josep Canadell, executive director of the Global Carbon Project.
"On our current path, we will find it extremely difficult to rein in carbon emissions enough to stabilise the atmospheric carbon dioxide concentration at 450ppm, and even 550ppm will be a challenge," he said.
"At some point in the near future, we will miss the boat in terms of achieving acceptable levels."
Based on current trends, carbon dioxide concentrations are likely to increase to 500ppm this century.  
The last time the planet experienced levels as high as 500ppm was about 20 or 40 million years ago, when sea levels were 100 metres higher than today.
The Stern report earlier this month warned that the uncontrolled release of greenhouse gases could lead to a rise in average global temperatures of up to 5C by 2100 - about the same temperature difference between now and the last ice age.
US 'green'
revolution
Nuclear
power
Scientist have warned that global temperatures will continue to rise for many decades after carbon dioxide concentrations have stabilised due to the environmental inertia of the world's climate system.
Dr Peter Falloon, a climate impact scientist at the Met Office's Hadley Centre, said the latest findings did not augur well for attempts at averting climate change.
"It's not what we want or hope to see.   The concern comes from the fact that the greater the emissions are now, the harder it will be to bring them down in the future," he said.
"It takes 30 or 40 years to realise the change in carbon dioxide emissions.   It highlights how important it is to take quick and effective action now."
Professor Bill McGuire, director of the Benfield Hazard Research Centre in London, said: "This is more very bad news. We need a 60 to 70 per cent cut in emissions, but instead, emission levels are spiralling out of control.
"The sum total of our meagre efforts to cut emissions amounts to less than zero."
©2006 Independent Digital (UK) Ltd.  All rights reserved
Tuesday, 14 March 2006
Sharp rise in CO2 levels recorded
By David Shukman
BBC science correspondent
Rocky mountains in Colorado.

Air samples taken from Colorado's Rocky Mountains show sharp rise in co2 level
Rocky mountains in Colorado.
Air samples have been taken from Colorado's Rocky Mountains
US climate scientists have recorded a significant rise in the concentration of carbon dioxide in the atmosphere, pushing it to a new record level.
BBC News has learned the latest data shows CO2 levels now stand at 381 parts per million (ppm) — 100ppm above the pre-industrial average.
The research indicates that 2005 saw one of the largest increases on record — a rise of 2.6ppm.
The figures are seen as a benchmark for climate scientists around the globe.
The US National Oceanic and Atmospheric Administration (Noaa) has been analysing samples of air taken from all over the world, including America's Rocky Mountains.
The chief carbon dioxide analyst for Noaa says the latest data confirms a worrying trend that recent years have, on average, recorded double the rate of increase from just 30 years ago.
"We don't see any sign of a decrease; in fact, we're seeing the opposite, the rate of increase is accelerating," Dr Pieter Tans told the BBC.
Mankind is changing the climate
Professor Sir David King,
UK chief scientific adviser
The precise level of carbon dioxide in the atmosphere is of global concern because climate scientists fear certain thresholds may be "tipping points" that trigger sudden changes.
The UK government's chief scientific adviser, Professor Sir David King, said the new data highlighted the importance of taking urgent action to limit carbon emissions.
"Today we're over 380 ppm," he said. "That's higher than we've been for over a million years, possibly 30 million years. Mankind is changing the climate".
Ice bubbles reveal biggest rise in CO2 for 800,000 years
By Steve Connor, Science Editor
Published: 05 September 2006
The rapid rise in greenhouse gases over the past century is unprecedented in at least 800,000 years, according to a study of the oldest Antarctic ice core which highlights the reality of climate change.
Air bubbles trapped in ice for hundreds of thousands of years have revealed that humans are changing the composition of the atmosphere in a manner that has no known natural parallel.
Scientists at the British Antarctic Survey (BAS) in Cambridge have found there have been eight cycles of atmospheric change in the past 800,000 years when carbon dioxide and methane have risen to peak levels.
Each time, the world also experienced the relatively high temperatures associated with warm, inter-glacial periods, which were almost certainly linked with levels of carbon dioxide and possibly methane in the atmosphere.
However, existing levels of carbon dioxide and methane are far higher than anything seen during these earlier warm periods, said Eric Wolff of the BAS.
"Ice cores reveal the Earth's natural climate rhythm over the last 800,000 years. When carbon dioxide changed there was always an accompanying climate change," Dr Wolff said. "Over the past 200 years, human activity has increased carbon dioxide to well outside the natural range and we have no analogue for what will happen next.
"We have a no-analogue situation. We don't have anything in the past that we can measure directly," he added.
The ice core was drilled from a thick area of ice on Antarctica known as Dome C.
The core is nearly 3.2km long and reaches to a depth where air bubbles became trapped in ice that formed 800,000 years ago.
"It's from those air bubbles that we know for sure that carbon dioxide has increased by about 35 per cent in the past 200 years.
Before that 200 years, which is when man's been influencing the atmosphere, it was pretty steady to within 5 per cent," Dr Wolff said.
The core shows that carbon dioxide was always between 180 parts per million (ppm) and 300 ppm during the 800,000 years.
However, now it is 380 ppm. Methane was never higher than 750 parts per billion (ppb) in this timescale, but now it stands at 1,780 ppb.
But the rate of change is even more dramatic, with increases in carbon dioxide never exceeding 30 ppm in 1,000 years — and yet now carbon dioxide has risen by 30 ppm in the last 17 years.
"The rate of change is probably the most scary thing because it means that the Earth systems can't cope with it," Dr Wolff told the British Association meeting at the University of East Anglia in Norwich.
"On such a crowded planet, we have little capacity to adapt to changes that are much faster than anything in human experience."

©2006 Independent Digital (UK) Ltd.  All rights reserved
 
Global warming to speed up as carbon levels show sharp rise
By Geoffrey Lean, Environment Editor
Published: 15 January 2006
Global warming is set to accelerate alarmingly because of a sharp jump in the amount of carbon dioxide in the atmosphere.
Preliminary figures, exclusively obtained by The Independent on Sunday, show that levels of the gas - the main cause of climate change — have risen abruptly in the past four years.
Scientists fear that warming is entering a new phase, and may accelerate further.
But a summit of the most polluting countries, convened by the Bush administration, last week refused to set targets for reducing their carbon dioxide emissions.
Set up in competition to the Kyoto Protocol, the summit, held in Sydney and attended by Australia, China, India, Japan and South Korea as well as the United States, instead pledged to develop cleaner technologies — which some experts believe will not arrive in time.
The climb in carbon dioxide content showed up in readings from the US government's National Oceanic and Atmospheric Administration, taken at the summit of Mauna Loa, Hawaii.
The measurements have been taken regularly since 1958 in the 11,400ft peak's pristine conditions, 2,000 miles from the nearest landmass and protected by unusual climatic conditions from the pollution of Hawaii, two miles below.
Through most of the past half-century, levels of the gas rose by an average of 1.3 parts per million a year; in the late 1990s, this figure rose to 1.6 ppm, and again to 2ppm in 2002 and 2003.
But unpublished figures for the first 10 months of this year show a rise of 2.2ppm.
Scientists believe this may be the first evidence that climate change is starting to produce itself, as rising temperatures so alter natural systems that the Earth itself releases more gas, driving the thermometer ever higher.

©2006 Independent Digital (UK) Ltd.  All rights reserved
Thursday, 24 November 2005
CO2 'highest for 650,000 years'
By Richard Black
Environment Correspondent, BBC News website
Microscope picture of gas bubbles in ice. 

Image: W. Berner/University of Bern
Microscope picture of gas bubbles in ice.
Gas bubbles trapped in ice store valuable climatic information
Current levels of the greenhouse gases carbon dioxide and methane in the atmosphere are higher now than at any time in the last 650,000 years.
That is the conclusion of new European studies looking at ice taken from 3km below the surface of Antarctica.
The scientists say their research shows present day warming to be exceptional.
Other research, also published in the journal Science, suggests that sea levels may be rising twice as fast now as in previous centuries.
Treasure dome
The evidence on atmospheric concentrations comes from an Antarctic region called Dome Concordia (Dome C).
Over a five year period commencing in 1999, scientists working with the European Project for Ice Coring in Antarctica (Epica) have drilled 3,270m into the Dome C ice, which equates to drilling nearly 900,000 years back in time.
Gas bubbles trapped as the ice formed yield important evidence of the mixture of gases present in the atmosphere at that time, and of temperature.
"One of the most important things is we can put current levels of carbon dioxide and methane into a long-term context," said project leader Thomas Stocker from the University of Bern, Switzerland.
"We find that CO2 is about 30% higher than at any time, and methane 130% higher than at any time; and the rates of increase are absolutely exceptional: for CO2, 200 times faster than at any time in the last 650,000 years."
Stable relationship
Ice core.

Image: W. Berner/University of Bern
Ice core.
Epica drills have extracted ice from 3km under the Antarctic surface
Last year, the Epica team released its first data. The latest two papers analyse gas composition and temperature dating back 650,000 years.
This extends the picture drawn by another Antarctic ice core taken near Lake Vostok which looked 440,000 years into the past.
The extra data is crucial because around 420,000 years there appears to have been a significant shift in the Earth's long-term climate patterns.
Before and after this date, the planet went through 100,000 year cycles of alternating cold glacial and warm interglacial periods.
But around the 420,000 year mark, the precise pattern changed, with the contrast between warm and cold conditions becoming much more marked.
The Dome C core gives data from six cycles of glaciation and warming; two from before this change, four from after.
"We found a very tight relationship between CO2 and temperature even before 420,000 years," said Professor Stocker.co2
"The fact that the relationship holds across the transition between climatic regimes is a very strong indication of the important role of CO2 in climate regulation."co2
Epica scientists will now try to extend their analysis further back in time.
Water rise
Antarctic base.

Image: A. Lori/ENEA
The base at Dome Concordia, Antarctic
Another study reported in the same journal claims that for the last 150 years, sea levels have been rising twice as fast as in previous centuries.
Using data from tidal gauges and reviewing findings from many previous studies, US researchers have constructed a new sea level record covering the last 100 million years.
They calculate the present rate of rise at 2mm per year.
"The main thing that's changed since the 19th Century and the beginning of modern observation has been the widespread increase in fossil fuel use and more greenhouse gases," said Kenneth Miller from Rutgers University.
The Intergovernmental Panel on Climate Change, the body which collates scientific evidence for policymakers, concludes that sea level rose by 1-2cm during the last century, and will rise by anything up to 88cm by the end of this century.
Carbon Dioxide Reported at Record Levels
By CHARLES J. HANLEY, AP Special Correspondent
A scientist works at Hawaii's Mauna Loa Observatory, 11,141 feet (3396 m) above sea level

The density of carbon dioxide in the atmosphere largley blamed for global warming has reached record high levels.
A scientist works at Hawaii's Mauna Loa Observatory, 11,141 feet (3396 m) above sea level on Friday March 19, 2004.
The density of carbon dioxide in the atmosphere largley blamed for global warming has reached record high levels.
(AP Photo/Richard Vogel)
MAUNA LOA OBSERVATORY, Hawaii — Carbon dioxide, the gas largely blamed for global warming, has reached record-high levels in the atmosphere after growing at an accelerated pace in the past year, say scientists monitoring the sky from this 2-mile-high station atop a Hawaiian volcano.
The reason for the faster buildup of the most important "greenhouse gas" will require further analysis, the U.S. government experts say.
"But the big picture is that CO2 is continuing to go up," said Russell Schnell, deputy director of the National Oceanic and Atmospheric Administration's climate monitoring laboratory in Boulder, Colo., which operates the Mauna Loa Observatory on the island of Hawaii.co2
Carbon dioxide, mostly from burning of coal, gasoline and other fossil fuels, traps heat that otherwise would radiate into space.
Global temperatures increased by about 1 degree Fahrenheit (0.6 degrees Celsius) during the 20th century, and international panels of scientists sponsored by world governments have concluded that most of the warming probably was due to greenhouse gases.
The climatologists forecast continued temperature rises that will disrupt the climate, cause seas to rise and lead to other unpredictable consequences — unpredictable in part because of uncertainties in computer modeling of future climate.
Before the industrial age and extensive use of fossil fuels, the concentration of carbon dioxide in the atmosphere stood at about 280 parts per million, scientists have determined.
Australia's Great Barrier Reef will lose most of its coral cover by 2050 and, at worst, the world's largest coral system could collapse by 2100 because of global warming, a study released on February 21, 2004.

The study by Queensland University's Center for Marine Studies, commissioned by the Worldwide Fund for Nature, said that the destruction of coral on the Great Barrier Reef was inevitable due to global warming, regardless of what actions were taken now.

A portion of the Great Barrier Reef is seen in this undated file photo.
Australia's Great Barrier Reef will lose most of its coral cover by 2050 and, at worst, the world's largest coral system could collapse by 2100 because of global warming, a study released on February 21, 2004.
The study by Queensland University's Center for Marine Studies, commissioned by the Worldwide Fund for Nature, said that the destruction of coral on the Great Barrier Reef was inevitable due to global warming, regardless of what actions were taken now.
A portion of the Great Barrier Reef is seen in this undated file photo.
Photo by Reuters (Handout)
That year-to-year increase of about 3 parts per million is considerably higher than the average annual increase of 1.8 parts per million over the past decade, and markedly more accelerated than the 1-part-per-million annual increase recorded a half-century ago, when observations were first made here.
Asked to explain the stepped-up rate, climatologists were cautious, saying data needed to be further evaluated. But Asia immediately sprang to mind.
"China is taking off economically and burning a lot of fuel. India, too," said Pieter Tans, a prominent carbon-cycle expert at NOAA's Boulder lab.
Average readings at the 11,141-foot Mauna Loa Observatory, where carbon dioxide density peaks each northern winter, hovered around 379 parts per million on Friday, compared with about 376 a year ago.
Another leading climatologist, Ralph Keeling, whose father, Charles D. Keeling, developed methods for measuring carbon dioxide, noted that the rate "does fluctuate up and down a bit," and said it was too early to reach conclusions. But he added: "People are worried about `feedbacks.' We are moving into a warmer world."
He explained that warming itself releases carbon dioxide from the ocean and soil. By raising the gas's level in the atmosphere, that in turn could increase warming, in a "positive feedback," said Keeling, of San Diego's Scripps Institution of Oceanography.
The Intergovernmental Panel on Climate Change projects that, if unchecked, atmospheric carbon dioxide concentrations by 2100 will range from 650 to 970 parts per million. As a result, the panel estimates, average global temperature would probably rise by 1.4 to 5.8 degrees Celsius (2.7 and 10.4 degrees Fahrenheit) between 1990 and 2100.
The 1997 Kyoto Protocol would oblige ratifying countries to reduce carbon dioxide emissions according to set schedules, to minimize potential global warming. The pact has not taken effect, however.
The United States, the world's biggest carbon dioxide emitter, signed the agreement but did not ratify it, and the Bush administration has since withdrawn U.S. support, calling instead for voluntary emission reductions by U.S. industry and more scientific research into climate change.

Copyright © 2004 The Associated Press.    All rights reserved.

Copyright © 2004 Yahoo! Inc.    All rights reserved.
Climate fear as carbon levels soar
Scientists bewildered by sharp rise of CO2 in atmosphere for second year running
Paul Brown, environment correspondent
Monday October 11, 2004

The Guardian
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 past.
Australia's koalas at risk from higher temperatures and specialized diet of food
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.co2
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.co2
Above or below average rises in CO2 levels in the atmosphere have been explained in the past by natural events.co2
When the Pacific warms up during El Niño — a disruptive weather pattern caused by weakening trade winds — the amount of carbon dioxide rises dramatically because warm oceans emit CO2 rather than absorb it.co2
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 Niño.
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 record."
Analysts stress that it is too early to draw any long-term conclusions.
But the fear held by some scientists is that the greater than normal rises in CO2 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.co2
That would herald the so-called "runaway greenhouse effect", where the planet's soaring temperature becomes impossible to contain.  As the icecaps melt, less sunlight is refected back into space from ice and snow, and bare rocks begin to absorb more heat.  This is already happening.
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.co2
Hong Kong
Power plant amendments for 2010 do not mention carbon dioxide
"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 Niño years.  Previously the only figures that climbed higher than 2 ppm were El Niño years — 1973, 1988, 1994 and 1998.co2
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 warming.
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."
David J Hofmann of the US National Oceanic and Atmospheric Administration centre, which also studies CO2, was more cautious.co2
"I don't think an increase of 2 ppm for two years in a row is highly significant — there are climatic perturbations that can make this occur," he said.  "But the absence of a known climatic event does make these years unusual.
"Based on those two years alone I would say it was too soon to say that a new trend has been established, but it warrants close scrutiny."
Guardian Unlimited © Guardian Newspapers Limited 2004
 
Global warming: passing the 'tipping point'
Our special investigation reveals that critical rise in world temperatures is now unavoidable
By Michael McCarthy, Environment Editor
Published: 11 February 2006
A crucial global warming "tipping point" for the Earth, highlighted only last week by the British Government, has already been passed, with devastating consequences.
Research commissioned by The Independent reveals that the accumulation of greenhouse gases in the atmosphere has now crossed a threshold, set down by scientists from around the world at a conference in Britain last year, beyond which really dangerous climate change is likely to be unstoppable.
The implication is that some of global warming's worst predicted effects, from destruction of ecosystems to increased hunger and water shortages for billions of people, cannot now be avoided, whatever we do.
It gives considerable force to the contention by the green guru Professor James Lovelock, put forward last month in The Independent, that climate change is now past the point of no return.
The danger point we are now firmly on course for is a rise in global mean temperatures to 2 degrees above the level before the Industrial Revolution in the late 18th century.
At the moment, global mean temperatures have risen to about 0.6 degrees above the pre-industrial era — and worrying signs of climate change, such as the rapid melting of the Arctic ice in summer, are already increasingly evident.
But a rise to 2 degrees would be far more serious.
By that point it is likely that the Greenland ice sheet will already have begun irreversible melting, threatening the world with a sea-level rise of several metres.
Agricultural yields will have started to fall, not only in Africa but also in Europe, the US and Russia, putting up to 200 million more people at risk from hunger, and up to 2.8 billion additional people at risk of water shortages for both drinking and irrigation.
The Government's conference on Avoiding Dangerous Climate Change, held at the UK Met Office in Exeter a year ago, highlighted a clear threshold in the accumulation of greenhouse gases such as carbon dioxide (CO2) in the atmosphere, which should not be surpassed if the 2 degree point was to be avoided with "relatively high certainty".co2
This was for the concentration of CO2 and other gases such as methane and nitrous oxide, taken together in their global warming effect, to stay below 400ppm (parts per million) in CO2 terms — or in the jargon, the "equivalent concentration" of CO2 should remain below that level.co2
The warning was highlighted in the official report of the Exeter conference, published last week.
However, an investigation by The Independent has established that the CO2 equivalent concentration, largely unnoticed by the scientific and political communities, has now risen beyond this threshold.co2
This number is not a familiar one even among climate researchers, and is not readily available.
For example, when we put the question to a very senior climate scientist, he said: "I would think it's definitely over 400 — probably about 420."
So we asked one of the world's leading experts on the effects of greenhouse gases on climate, Professor Keith Shine, head of the meteorology department at the University of Reading, to calculate it precisely.
Using the latest available figures (for 2004), his calculations show the equivalent concentration of CO2, taking in the effects of methane and nitrous oxide at 2004 levels, is now 425ppm.
This is made up of CO2 itself, at 379ppm; the global warming effect of the methane in the atmosphere, equivalent to another 40ppm of CO2; and the effect of nitrous oxide, equivalent to another 6ppm of CO2.co2
The tipping point warned about last week by the Government is already behind us.
"The passing of this threshold is of the most enormous significance," said Tom Burke, a former government adviser on the green issues, now visiting professor at Imperial College London.
"It means we have actually entered a new era — the era of dangerous climate change.   We have passed the point where we can be confident of staying below the 2 degree rise set as the threshold for danger.   What this tells us is that we have already reached the point where our children can no longer count on a safe climate."
The scientist who chaired the Exeter conference, Dennis Tirpak, head of the climate change unit of the OECD in Paris, was even more direct.
He said: "This means we will hit 2 degrees [as a global mean temperature rise]."
Professor Burke added: "We have very little time to act now.   Governments must stop talking and start spending.   We already have the technology to allow us to meet our growing need for energy while keeping a stable climate.   We must deploy it now.   Doing so will cost less than the Iraq war so we know we can afford it."
The 400ppm threshold is based on a paper given at Exeter by Malte Meinhausen of the Swiss Federal Institute of Technology.
Dr Meinhausen reviewed a dozen studies of the probability of exceeding the 2 degrees threshold at different CO2 equivalent levels.
Taken together they show that only by remaining above 400 is there a very high chance of not doing so.co2
Some scientists have been reluctant to talk about the overall global warming effect of all the greenhouses gases taken together, because there is another consideration — the fact that the "aerosol", or band of dust in the atmosphere from industrial pollution, actually reduces the warming.
As Professor Shine stresses, there is enormous uncertainty about the degree to which this is happening, so making calculation of the overall warming effect problematic.
However, as James Lovelock points out — and Professor Shine and other scientists accept — in the event of an industrial downturn, the aerosol could fall out of the atmosphere in a matter of weeks, and then the effect of all the greenhouse gases taken together would suddenly be fully felt.

©2006 Independent Digital (UK) Ltd.  All rights reserved

 
 
 
 
 
For archive purposes, this article is being stored on TheWE.cc website.
The purpose is to advance understandings of environmental, political,
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