VOA常速英语:Ancient Ice Helps Predict Future Warming Trend

Jim White studies really old ice. He thinks it will help predict what the climate will be like in the future.

White is director of the Institute of Arctic and Alpine Research at the University of Colorado at Boulder and lead U.S. investigator on the North Greenland Eemian Ice Drilling project or NEEM.

NEEM is about trying to get a good record of the last interglacial period from Greenland 120,000 to 130,000 years ago when Greenland was two to three degrees Celsius warmer than it is today, he says. "And thus it represents our closest analogue in time to where we are going in the future."

 

White is a member of an international team of scientists that, over five years, has drilled 2.5 kilometers to bedrock to extract a 2,500 meter-long ice core in three-to-four meter chunks. And once they come up to the surface, he says, "We measure, we log and we match to make sure that we know that we're getting a continuous record."

Scientists calculate greenhouse gas content and air temperature from gases trapped in the ice. And from captured dust, rock and plant material they get a closer look at what Greenland was like before it was covered with snow.

 

White says during the Eemian period sea level rose approximately five meters. He is uncertain how much of that ice came from Greenland because, he says, "The dynamics of the Greenland ice sheet are not the same as the dynamics of Antarctica, which is our other big source of land ice that can raise or lower sea level."

The fate of Greenland under a warm climate, White says won't be the same as west Antarctica and east Antarctica.

Answers to those questions, he says, can provide decision-makers with information they need to set policy for expected sea level rise given the temperature on the planet. "It makes a big difference whether it is one or five meters," he says.

NEEM ice cores were studied on site and also have been sent to laboratories across the world for analysis. White expects the data to be published early in 2011.