Feb. 26 (Bloomberg) -- Atmospheric levels of carbon dioxide are at their highest in 820,000 years, scientists examining a 3- kilometer (2-mile) ice core from Antarctica have found.

Carbon dioxide acts to warm the Earth by trapping the sun's energy. The United Nations Intergovernmental Panel on Climate Change on Feb. 2 said man-made emissions of greenhouse gases like CO2 are very likely causing global warming, and warned that average temperatures may rise by as much as 6.4 degrees Celsius (11.5 Fahrenheit), and sea-levels by 59 centimeters (23 inches) by 2100.

In November 2005, scientists working on the European Project for Ice Coring in Antarctica (EPICA) wrote in the journal Science that the carbon dioxide levels haven't been exceeded at any point in the past 650,000 years. Scientists have since analyzed the remainder of the 3,270-meter ice core, and are likely to publish their results ``fairly soon,'' said Eric Wolff, of the British Antarctic Survey, which was a partner on the project.

``The top line answer that we've said for the 650,000 years would be the same, except we could lengthen the time period to 820,000 years,'' Wolff said in an interview in London at an event to mark the start of International Polar Year, a concerted drive to gather scientific data about Antarctica and the Arctic. ``The concentrations that we're seeing now are still the highest.''

Carbon dioxide in 2005 reached a concentration of 379.1 parts per million, the World Meteorological Organization said on Nov. 3. That's the highest level ever recorded, and an increase of more than a third from 280 ppm since industrialization began in the late 1700s. the historic level for 650,000 years fluctuated in a band broadly between 180 ppm and 300 ppm.

Historic Concentrations

The historic concentrations of so-called greenhouse gases can be determined by examining air bubbles trapped in the ice thousands of years ago. While the ice core analyzed extends back 890,000 years, the bottom 70,000 years' worth of ice core isn't useable, Wolff said, adding that his European colleagues working on the study haven't yet submitted a paper for publication.

``They're trying to cross the `T's' and dot the `I's' before they submit it,'' he said.

Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Sweden, Switzerland and the United Kingdom all contributed scientists and funding to the EPICA drilling program. The Ice core was extracted from the Concordia Dome C scientific base at about 75 degrees south on the Antarctic plateau.

International Polar Year (IPY) includes 228 different studies involving 50,000 scientists, students and support staff in more than 60 countries. Those projects will generate a total investment of $1.7 billion in polar studies, about two thirds of it funded already, according to IPY Director David Carlson.

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net.

Last Updated: February 26, 2007 08:16 EST