Influence of natural and anthropogenic carbon dioxide sequestration on global warming

The increase in the global surface temperature is influenced by several factors including anthropogenic and natural emissions of CO2, and the ability of natural sequestration reservoirs in the Earth's oceans and land to absorb and store it. The CO2 absorption in these reservoirs is sensitive to changes in the global temperature and the atmospheric CO2 concentration, thus creating a feedback loop in the Earth's ecosystem, which complicates predictions of the overall impact of rising atmospheric CO2 levels on global warming. Here, we model this interaction through a positive feedback loop and utilize general circulation models (GCM) to quantify the coupling between the carbon-cycle and the global temperature. We validate the model by comparing its predictions with those from high fidelity simulations and historical records. Thereafter, we investigate the impact of anthropogenic CO2 sequestration on lowering the rate of increase in the global temperature and find that a reduction in global warming is more sensitive to larger sequestration fractions. Thus, an inordinately large fraction of CO2 emissions would have to be sequestered to significantly impact global warming. (C) 2012 Elsevier B.V. All rights reserved.