The Response of the Terrestrial Biosphere to Urbanization: Land Cover Conversion, Climate, and Urban Pollution

In this study we quantify effects of urban areas on the carbon cycle in Europe accounting for: (1) proportion of impervious land, (2) local urban climate, (3) urban CO2 concentrations, and (4) elevated atmospheric nitrogen deposition. We use a terrestrial ecosystem model to estimate biosphere-to-atmosphere carbon fluxes in response to these urban factors. It was found that fertilization effects from CO2 and the atmospheric nitrogen deposition made the strongest positive contributions to the carbon uptake (0.023 Pg C year and 0.039 Pg C year, respectively), whereas, the impervious urban land and local urban climate resulted in a reduction of carbon uptake (−0.005 Pg C year and −0.007 Pg C year, respectively). The synergetic effect of the four factors was 0.058 Pg C year increase of the carbon sequestration in Europe.