Carbon futures: a valiant attempt to bring scientific order from modeling chaos

The global carbon cycle, the continual exchange of carbon between the oceans, terrestrial ecosystems and the atmosphere, provides a massive subsidy to the human enterprise, absorbing roughly half of fossil fuel and land use emissions of CO2 and thus reducing the climate impact of the human enterprise by half (Le Quéré et al 2015). The uptake of CO2 by the oceans and land plants is due to feedbacks between atmospheric CO2, climate and the terrestrial and marine reservoirs of carbon. The net effect of these Earth System feedbacks is to translate emissions of CO2 into atmospheric concentrations that are about half of what they would be otherwise (Figure 1). If the strength of these feedbacks were to change, that the impact on climate of human emissions will change.