The climate sensitivity of land cover change and its thermodynamic characterization

One of the main drivers of land cover change is the appropriation of terrestrial productivity by humans to meet their demand for food supply and other ecosystem services. I estimate the climate sensitivity to land cover change with a novel approach that is based on the concept of "human appropriation" and incorporate it into a coupled dynamic vegetation-atmosphere model. In this approach, a fraction of simulated terrestrial productivity is "appropriated" by humans, therefore unavailable for vegetation growth, which in turn affects land surface functioning and climate. The climate sensitivity is then obtained from a range of sensitivity simulations for different intensities of "human appropriation". The simulations show a consistent trend in climatic conditions that are less favorable to vegetation productivity with increasing levels of appropriation. Globally averaged land surface temperature is, however, insensitive, thus making the climate sensitivity of land cover change difficult to compare to the climate sensitivity to elevated concentrations of atmospheric carbon dioxide. I motivate the use of entropy production as a thermodynamic metric of climate sensitivity, which measures the intensity of dissipative climate system processes. I show that entropy production captures the climate sensitivity very well (in contrast to global mean surface temperature) and it would seem to be a more appropriate metric to characterize the climate sensitivity to land cover change.