Sept. 25, 2006 — Earth's climate is now moving into unknown territory — warming up more than any time in the last 12,000 years, report top U.S. climate researchers. Accelerated warming over the last 30 years has pushed up world surface temperatures to the highest they've been since the last ice age ended.
And the mercury is still rising.
That means there is no time to waste in slowing the burning of fossil fuels that releases the majority of greenhouse gases which, in turn, are causing the warming, say the researchers.
The alarming conclusion is based on climate data gathered from instruments around the world over the last century, combined with ancient paleoclimate data from ocean sediments. The conclusions are reported in a paper in the current issue of the Proceedings of the National Academy of Sciences.
The paleoclimate data indicate more than just a 12,000-year record on the brink of being smashed. We are now closing in on the warmest climate for any of the warm periods between ice ages — called interglacials — in the last million years, said James Hansen of NASA's Goddard Institute for Space Studies.
"We're within one degree Celsius (1.8 degrees Fahrenheit) of the warmest interglacial," Hansen told Discovery News.
That's a crucial degree, he said. If warming can be held below that level, the effects of global warming should stay within those of other interglacials, which were fairly similar to today.
"But if further global warming reaches 2 or 3 degrees Celsius," said Hansen, "we will likely see changes that make Earth a different planet than the one we know."
