For Swiss physicist and climate modeling expert Thomas Stocker, cores from the ice sheets of Greenland and Antarctica provide clear links between carbon dioxide and warm global temperatures — and a pretty clear picture of the future.

The Greenland data go back 120,000 years, to a time when there wasn't ice on Greenland. And the Antarctic data go back 650,000 years. Scientists are able to extract as many as 50 different kinds of information from the ice, including the chemical composition of the atmosphere when it was deposited and the temperature at the time each layer froze.

Stocker, a professor at the Swiss University of Bern, is spending his sabbatical working with fellow climate scientists at the University of Hawai'i's International Pacific Research Center, among them researcher Oliver Timm and oceanography associate professor Axel Timmermann.

Stocker's predictions are sobering. In general, during the past several hundreds of thousands of years, ice ages occurred during periods when there were about 200 parts per million of carbon dioxide in the atmosphere. Warm periods occurred when there were 280 parts per million of carbon dioxide in the atmosphere.

Today's atmospheric carbon dioxide stands at 384 parts per million.

"The current increase of carbon dioxide is about 100 times faster than anything we've seen in the last 650,000 years," he said.

"Even if we stopped burning fossil fuels entirely right now, it would take from 200 to 500 years for the carbon dioxide level to get back to 310, where it was in 1980," Stocker said. And that's still significantly higher than the level during the warm spells of the past few hundred thousand years.

Precisely predicting temperatures is difficult, in part because a lot of factors are involved, including how much heat and carbon dioxide are sucked up by the oceans. But to Stocker, the fundamental message is that the world will get warmer, pure and simple. The rate can be slowed by drastic action, which he considers unlikely, but it can't be stopped for the next several human generations.

He said some areas will become hotter and heat waves may be more common, though a few areas may cool. Some areas may be stormier and the storms stronger, but "there will be certain areas that will have less extreme weather." Seas will certainly rise. "Costs will be enormous, and the benefit will not outweigh the costs that are increased by climate change," he said.