Nitrogen’s detrimental effects on the climate roughly correspond to its climactic benefits, found researchers around the team of Sönke Zaehl, Max Planck Institute for Biogeochemistry, Germany.
Human nitrogen additions – fertilizers in agriculture – are the principle cause for the increase in terrestrial nitrous oxide emission since 1960 and contribute to about one fifth of the current global net carbon uptake (1996–2005). The climatic effects of the anthropogenic nitrogen perturbation from CO2 and N2O are very substantial but of opposite signs. The cooling effect due to enhanced carbon uptake of the terrestrial biosphere is more than compensated for by the warming effects from enhanced terrestrial N2O emissions.
The study highlights the relevance of anthropogenic nitrogen in the climate system and the need to consider the effects of carbon and nitrogen cycling jointly.