According to a UCLA press release issued October 8, 2009, a study in the October 8, 2009 edition of Science suggests that the last time that CO2 levels were as high as today — and were at those levels over sustained periods of time — the earth was 5 to 10 degrees warmer Fahrenheit, there was no permanent ice at the Arctic, less ice in the Antarctic, and sea levels were around 75 to 120 feet higher than today,

The authors of the report — let by assistant professor Aradhna Tripati of UCLA’s department of Earth and space sciences and department of atmospheric and oceanic sciences, in conjunction with professors from Cambridge and Cal Tech — seem to be speculating/assessing based upon best available information and methodology.  Of significance, they have also been able to verify their methodology as empirically sound at least in so far as being able to measure it against otherwise known data.

“We are able, for the first time, to accurately reproduce the ice-core record for the last 800,000 years — the record of atmospheric C02 based on measurements of carbon dioxide in gas bubbles in ice,” Tripati said. “This suggests that the technique we are using is valid.

“We then applied this technique to study the history of carbon dioxide from 800,000 years ago to 20 million years ago,” she said.

Tripati also claims that the findings are more fact than speculation, with a low margin of error, and also notes:

“A slightly shocking finding,” Tripati said, “is that the only time in the last 20 million years that we find evidence for carbon dioxide levels similar to the modern level of 387 parts per million was 15 to 20 million years ago, when the planet was dramatically different.”

According to Tripati, the Arctic ice cap formed around 14 million years ago, and has been here ever since. CO2 levels, which the authors found to be correlated with temperatures going back 20 million years ( just like earlier ice core studies that found a correlation between average temperature and CO2 levels going back 800,000 years), are higher than they have been going back 14 million years. And are rising, every year.