Monday, December 7, 2009

Earth is extremely sensitive to carbon dioxide

The new study published in Nature Geoscience has come up with the conclusion that in the long-term our planet's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated. Dan Lunt, from the University of Bristol, and colleagues compared results from a global climate model to temperature reconstructions of the Earth's environment three million years ago when global temperatures and carbon dioxide concentrations were relatively high, significantly higher than today. The temperature reconstructions were calculated using data from three million-year-old sediments on the ocean floor.

What scientists found out was that given the concentrations of carbon dioxide prevailing three million years ago, the model originally predicted a significantly smaller temperature increase than that indicated by the reconstructions, meaning some important factors were missing from the model. These important factors that need to be included in the model are land-ice and vegetation because changes in vegetation and ice lead to more sunlight being absorbed, which in turn increases warming on our planet.

Most of current climate models do not fully include these long-term processes, thus these models do not entirely represent the sensitivity of the Earth's temperature to carbon dioxide, and if we want to avoid dangerous climate change, this high sensitivity of the Earth to carbon dioxide should be taken into account when defining targets for the long-term atmospheric CO2 stabilization.

This study is also an important indicator on how studying Earth's past climate can provide important insights into how the Earth's climate and temperatures might change in the future.

Our planet's temperature is much more sensitive to carbon dioxide than previously thought.