CO2 higher today than last 2.1 million years

Study offers detailed look at past greenhouse gas levels

		IMAGE: This is Bärbel Hönisch with a mass spectrometer used to measure boron isotopes to reconstruct past CO2. Click here for more information.

Researchers have reconstructed atmospheric carbon dioxide levels over the past 2.1 million years in the sharpest detail yet, shedding new light on its role in the earth's cycles of cooling and warming.