De Independent bericht:
Global Warming: The vicious circle.
By Steve Connor, Science Editor
By Steve Connor, Science Editor
The effects of man-made emissions of carbon dioxide are being felt on every inhabited continent in the world with very different parts of the climate now visibly responding to human activity.
These are among the main findings of the most intensive study of climate change by 2,000 of the world's leading climate scientists. They conclude that there is now little doubt that human activity is changing the face of the planet.
In addition to rising surface temperatures around the world, scientists have now linked man-made emissions of greenhouse gases to significant increases in ocean temperatures, rises in sea levels and the dramatic melting of Arctic sea ice over the past 35 years.
A draft copy of the fourth report of the Intergovernmental Panel on Climate Change (IPCC) says that global temperature rises this century of between 2C and 4.5C are almost inevitable. Ominously, however, it also says that much higher increases of 6C "or more" cannot be ruled out.
The final version of the IPCC's latest report is to be published on Friday but a draft copy, seen by The Independent, makes it clear that climate change could be far worse than previously thought because of potentially disastrous "positive" feedbacks which could accelerate rising temperatures.
A warmer world is increasing evaporation from the oceans causing atmospheric concentrations of water vapour, a powerful greenhouse agent, to have increased by 4 per cent over the sea since 1970. Water vapour in the atmosphere exacerbates the greenhouse effect. This is the largest positive feedback identified in the report, which details for the first time the IPCC's concern over the uncertainties - and dangers - of feedback cycles that may quickly accelerate climate change.
All the climate models used by the IPCC also found that rising global temperatures will erode the planet's natural ability to absorb man-made CO2. This could lead to CO2 concentrations in the atmosphere rising by a further 44 per cent, causing global average temperatures to increase by an additional 1.2C by 2100.
The IPCC's Fourth Assessment Report will go further than any of its three previous reports in linking the clear signs of global climate change with increases in man-made emissions of CO2 and other greenhouse gases since the start of the Industrial Revolution.
"Confidence in the assessment of the human contributions to recent climate change has increased considerably since the TAR [Third Assessment Report]," says the draft report. This is due to the stronger signs of climate change emerging from longer and more detailed records and scientific observations, it says.'
These are among the main findings of the most intensive study of climate change by 2,000 of the world's leading climate scientists. They conclude that there is now little doubt that human activity is changing the face of the planet.
In addition to rising surface temperatures around the world, scientists have now linked man-made emissions of greenhouse gases to significant increases in ocean temperatures, rises in sea levels and the dramatic melting of Arctic sea ice over the past 35 years.
A draft copy of the fourth report of the Intergovernmental Panel on Climate Change (IPCC) says that global temperature rises this century of between 2C and 4.5C are almost inevitable. Ominously, however, it also says that much higher increases of 6C "or more" cannot be ruled out.
The final version of the IPCC's latest report is to be published on Friday but a draft copy, seen by The Independent, makes it clear that climate change could be far worse than previously thought because of potentially disastrous "positive" feedbacks which could accelerate rising temperatures.
A warmer world is increasing evaporation from the oceans causing atmospheric concentrations of water vapour, a powerful greenhouse agent, to have increased by 4 per cent over the sea since 1970. Water vapour in the atmosphere exacerbates the greenhouse effect. This is the largest positive feedback identified in the report, which details for the first time the IPCC's concern over the uncertainties - and dangers - of feedback cycles that may quickly accelerate climate change.
All the climate models used by the IPCC also found that rising global temperatures will erode the planet's natural ability to absorb man-made CO2. This could lead to CO2 concentrations in the atmosphere rising by a further 44 per cent, causing global average temperatures to increase by an additional 1.2C by 2100.
The IPCC's Fourth Assessment Report will go further than any of its three previous reports in linking the clear signs of global climate change with increases in man-made emissions of CO2 and other greenhouse gases since the start of the Industrial Revolution.
"Confidence in the assessment of the human contributions to recent climate change has increased considerably since the TAR [Third Assessment Report]," says the draft report. This is due to the stronger signs of climate change emerging from longer and more detailed records and scientific observations, it says.'
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