By MARTIN MITTELSTAEDT
Toronto Globe and Mail
February 01, 2007
The draft, seen by the Toronto Globe and Mail on Tuesday, also says evidence that the world is heating up is now so strong that it is "unequivocal" and predicts more frequent heat waves, droughts and rain storms, as well as more violent typhoons and hurricanes. It concludes that the higher temperatures observed during the past 50 years are so dramatically different from anything in the climate record that the last half-century period was likely the hottest in at least the past 1,300 years.
Eleven of the past 12 years rank among the warmest since humans began taking accurate temperature measurements in the 1850s, a record of extremes so pronounced it is unlikely to be due to chance.
"Warming of the climate system is unequivocal, as is now evident from increases in global average air and ocean temperatures, melting of snow and ice, and rising sea level," says the draft, which is being reviewed in Paris before its formal release Friday by the Intergovernmental Panel on Climate Change.
The draft also makes projections of how the climate is likely to change over this century:
- Sea ice will shrink in both the Arctic and Antarctic, and late-summer sea ice in the Arctic could disappear almost entirely by the latter part of the 21st century.
- Heat waves and storms involving heavy precipitation will continue to become more common, as will droughts.
- The number of hurricanes will decrease, but the ones that do occur will be more powerful.
- Ocean currents responsible for such things as the Gulf Stream will slow, possibly by as much as 25 percent. The report said it's "very unlikely" that currents will have abrupt changes during the 21st century, but longer-term alterations "cannot be assessed with confidence."
The report is the fourth to be issued by the United Nations-organized group of scientists, and draws on contributions of about 2,000 top experts from around the world.
The panel's findings have evolved since the first was issued in 1990, becoming more confident over time that human activity - mainly the burning of fossil fuels, deforestation and large-scale agriculture - have been causing profound changes on the climate.
The first report suggested global warming might be happening. The second, in 1995, said it was likely to be under way, while the third, in 2001, had a tone that indicated scientists were pretty sure they were seeing humanity's fingerprints on changes in climate.
Given the stark tenor of the draft scientists are now considering, they seem absolutely sure that climate change is happening.
The draft says evidence of warming is now being found almost everywhere in the world, from the tops of mountains, where glaciers are in retreat, to ocean deeps, where the average water temperatures have increased.
Some environmentalists are predicting that a strongly worded IPCC report will dispel any lingering doubts that global warming is really happening, and are calling on politicians to start taking more sweeping action to limit emissions of the greenhouse gases blamed for climate change.
The United Nations' top environment official is calling for an emergency climate-change summit later this year.
The IPCC report will be issued in four installments over the course of the year. The first section, now being prepared, deals with all new scientific evidence assembled since 2001 on how the world's climate has been changing. The others will deal with specific topics, such as how humans can adapt to climate change and mitigate its effects.
Scripps Howard News Service, http://www.scrippsnews.com
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