Although the Intergovernmental Panel on Climate Change ("IPCC") is not scheduled to release its fourth report on the science of global climate change on February 2, 2007, a few details of the report's contents have begun to leak out. The report will include the bold pronouncement that
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.
Here are some other significant statements the report will make:
The anthropogenic release of greenhouse gases has already altered the earth's atmosphere so severely that the effects of global climate may already be locked in for at least 1000 years.
Current atmospheric concentrations of the greenhouse gases, carbon dioxide and methane, "far exceed" concentrations known to have existed over the last 650 000 years.
The Artic Ocean could be entirely ice-free in summertime by the end of the 21st Century.
Heat waves and droughts will increase in frequency.
Hurricanes will become more severe, though less frequent.
Global mean surface temperatures will most likely increase by between 1.7 and 4.0 degrees Celsius over the next century.
Sea levels will most likely increase by between 0.28 and 4.5 metres, though there is a significant probability that the Greenland iceshelves will melt completely, eventually raising sea levels by about 7 metres.
The full report will be sure to include myriad more predictions and assessments of risk when it is released in a couple of days. What seems clear already is that, where world scientific consensus included relatively general predictions accompanied by generous error margins only several years ago, current predictions have increased significantly in both magnitude and specificity.