OK, history fans, here’s a report that digs into the past. Reuters has a story about a study of the atmosphere based on old ice:

Greenhouse gases are at higher levels in the atmosphere than at any time in at least 800,000 years, according to a study of Antarctic ice on Wednesday that extends evidence that mankind is disrupting the climate.

Carbon dioxide and methane trapped in tiny bubbles of air in ancient ice down to 3,200 meters (10,500 ft) below the surface of Antarctica add 150,000 years of data to climate records stretching back 650,000 years from shallower ice drilling.