Worried about another ice age? In a study out Wednesday, a group of scientists says not to worry, at least not for the next 15,000 years or so.
They drilled nearly two miles into the Antarctic ice to produce the oldest-ever continuous climate record, from an ice core dating back 740,000 years. That's nearly twice as long as any other ice core record.
It shows eight ice ages, or glacials, followed by shorter interglacial periods and changing concentrations of gases and particles in the atmosphere.
The period that corresponds most to the present interglacial period, which started 12,000 years ago, was about 400,000 years ago and lasted roughly 28,000 years.
“Our data say we won’t go into another ice age. We have 15,000 years before that is coming,” Dr. Eric Wolff, of the British Antarctic Survey, told a news conference.
Warming concern remains
But, he added in a written statement, "we may have a heat wave if we are unable to control CO2 (carbon dioxide) emissions and other greenhouse gases entering the atmosphere."
Wolff said today's high concentrations of greenhouse gases, which many scientists tie to manmade burning of fossil fuels, are the highest seen in the last 440,000 years.
“We have no experience of (this) in the past,” said Wolff.
The scientists now plan to extract air from tiny bubbles in the ice to determine how the atmosphere’s composition has varied. "Our next step is to investigate CO2 in the ice cores and by understanding what has driven the natural changes seen in the ice record, we will create better models to predict how climate might change in the future," Wolff stated.
Scientists from 12 research centers in 10 European countries have worked on the eight-year European Project for Ice Coring in Antarctica. Their first results were published Wednesday in the science journal Nature.
Deeper drilling planned
They plan to drill 100 yards further in December to reach ice that is 900,000 to one million years old.
Drilling is limited to just two months of the year, December and January, because the average annual temperatures are below -65 Fahrenheit. Blizzards are common and the scientists travel hundreds of miles by tractor to work on the project on east Antarctica's plateau.
“Antarctica has now yielded the longest ice-core record yet, one that covers a staggering 740,000 years with more to come,” Jerry McManus, of the Woods Hole Oceanographic Institution in Massachusetts, said in a commentary in Nature.
James White, a geological sciences professor at the University of Colorado-Boulder, heralded the core record as providing scientists "a first shot at looking at climate and greenhouse gases during interglacial periods when humans had nothing to do with climate change."
"This has the potential to separate the human-caused impacts from the natural and place it in a much clearer context," he said.