| Friday, February 02, 2007 |
| UN study blames humans for global warming |
Weather goes wild, temperatures rise; humans are responsible for global warming.
In its most comprehensive report so far on climate change, the United Nations has said global warming is "very likely" caused by humans.
Temperatures and sea levels will rise by the end of this century.
Global temperatures are likely to rise by 1.1 to 6.4 degrees Celsius by the end of this century compared to the previous century, with a probable 2-4 degree range if carbon dioxide doubles from pre-industrial levels, the United Nations Inter-governmental Panel on Climate Change (IPCC) said in its report.
Sea-level gain over the same period may range from 18 to 59 centimetres (7 to 23 inches).
There is a key change in the report's language from that used in the panel's 2001 document - showing that there is more certainty that human activity is causing the warming.
The report, released to reporters in Paris, puts the probability of the link with humans at over 90 %, compared to the 66-90 % likelihood signalled in 2001.
"This report puts a full stop behind the questioning of the science underlying the issue of whether humans are causing global warming," Achim Steiner, director of the UN Environment Programme, said in Paris.
The global atmospheric concentration of carbon dioxide (CO2) stood at 379 parts per million in 2005 - up from about 280 ppm in 1750 - before the industrial revolution. Concentrations of CO2, and methane, another greenhouse gas, exceed "by far" the highest in an Antarctic ice-core record stretching back 650,000 years.
Those increases are primarily attributable to fossil fuel use and land-use change.
The UN panel released part one of a four-volume survey, which was reviewed by over 2,500 scientists from 130 countries.
"The science of climate change, of global warming, is now unambiguous: the earth is getting hotter, the weather is becoming more variable and this is due to our own industrial revolution," Britain's Environment Secretary David Miliband had said in an interview on January 31. "All the predictions are that the problem is becoming more urgent, that the scientists are becoming more certain and that the dangers are becoming more real."
Scientists say that carbon dioxide and other gases produced by burning fossil fuels cause the earth to heat up when they linger in the atmosphere, trapping energy from the sun that would otherwise reflect back into space.
Scientists say that melting of Greenland’s ice sheet increased dramatically in the past few years, with one portion losing ice five times faster in the past two years than the previous year and a half.
Sea-level forecasts will be under more scrutiny following a report on Thursday in Science, which says that levels since 1993 have risen by 3.3 millimetres a year.
Many industrialised nations have already begun taking action by setting caps on emissions. Under the UN’s Kyoto Protocol treaty, 35 countries and the European Union have agreed to cut emissions of greenhouse gases by a combined 5 % from the 1990 levels by the 2008-2012 period.
The US and Australia did not ratify the treaty, and developing nations such as India and China are not subject to emissions reductions.Labels: Tech |
| posted by a correspondent @ 10:37 AM |
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