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New Atmospheric Carbon Dioxide Study - Posted at 9:55 AM on Jun. 22, 2009 by ausetute
Atmospheric carbon dioxide levels for the last 2.1million years have been reconstructed in the greatest detail yet by analyzing the shells of single-celled plankton buried in the Atlantic Ocean off the coast of Africa.
The study has found that a drop in carbon dioxide is not the cause for earth's ice ages growing longer and more intense about 850,000 years ago, but it confirms that higher carbon dioxide levels coincide with warmer intervals.
Peak carbon dioxide levels over the past 2.1million years averaged about 280ppm, but today carbon dioxide is at 385ppm, 38% higher.
About 55 million years ago a large and rapid increase in carbon dioxide caused large scale extinctions in bottom-dwelling ocean creatures and dissolved a lot of shells as the ocean became more acidic. The researchers now believe they will have to find a way to study these carbon dioxide changes in greater detail further back in the past.

Atmospheric Carbon Dioxide Concentrations Across the Mid-Pleistocene Transition. Science, June 19, 2009
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