IPCC Scientists say fossil fuel use is main cause of climate change
Sat 03 February 2007
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In the first of four reports to be published this year, the Intergovernmental Panel on Climate Change (IPCC) said that the main source of increased CO2 concentrations in the atmosphere is fossil fuel use and that it is 'very likely' that climate change is induced by human activity.
The Panel said that evidence of warming is now 'unequivocal' and that global average temperatures are expected to increase by between 1.8 and 4 degrees celsius by 2100 and that this warming will have some very serious consequences.
The IPCC projected that sea levels are most likely to rise by 28-43cm and that climate change is likely to influence the intensity of tropical storms. The countries likely to be most affected include Bangladesh and Vietnam but low-lying or coastal cities - including London - are also under threat.
The IPCC's latest report is its first full assessment since 2001 of the science behind climate change. The IPCC includes 2,500 top scientists from 130 countries. It represents the panel's strongest warning yet over climate change. It says that better modelling has improved scientific knowledge and "considerably" increased the level of confidence in predictions compared with previous assessments.
According to a report in ENDS, the key scientific findings of the IPCC's latest report are:
* Global average surface temperature has risen by around 0.74 degrees Celsius over the past hundred years. The figure is higher than the Panel's last estimate of 0.6 degrees, due to a series of extremely warm years since 2001
* Predictions for the period 1990-2100 show an increase in temperature between 1.8-4 degrees, a slightly narrower range compared with the previous estimate of 1.4-5.8 degrees.
* Concentrations of carbon dioxide have already risen from a pre-industrial level of 280 parts per million (ppm) to around 379ppm in 2005, while methane levels have risen from 715 parts per billion (ppb) to 1,774ppb over the same period.
* Greenhouse gas levels of 650ppm CO2 equivalent are likely to increase temperature by around 3.6 degrees, while 750ppm would lead to a 4.3 degree increase. Future levels are difficult to predict as they will depend on factors including economic growth, new technologies and policies, the scientists stress.
* Sea levels are likely to rise in the range of 18-59cm over the same period. The predicted range is also narrower compared with the previous estimate (9-88cm).
* Regarding sea ice, the Arctic sea ice has already shrunk by about 2.7 per cent per decade since 1978, with the summer minimum declining by about 7.4 per cent. However, there is no evidence of such a trend in the Antarctic.
* It is "very likely" that precipitation will increase at high latitudes such as Europe and America and "likely" it will decrease over most subtropical land regions.
* There is evidence of an increase in the number of strong tropical cyclones, including hurricanes and typhoons, since the 1970s and this seems correlated with a rise in sea surface temperature. No changes have been observed for other phenomena such as tornadoes, lightning and dust-storms.
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