Effects of Increases in Atmospheric CO2 and Nitrogen Deposition on the Productivity of the Terrestrial Biosphere
Churkina, G., Brovkin, V., von Bloh, W., Trusilova, K., Jung, M. and Dentener, F. 2009. Synergy of rising nitrogen depositions and atmospheric CO2 on land carbon uptake moderately offsets global warming. Global Biogeochemical Cycles 23: 10.1029/2008GB003291.
Churkina et al. first determined that their global- and continental-scale estimates of land carbon uptake in the 1990s were "consistent with previously reported data." This comparison with the real world gave them confidence in the results their modeling exercise projected for the future, namely, that "increasing nitrogen deposition and the physiological effect of elevated atmospheric CO2 on plants have the potential to increase the land carbon sink, to offset the rise of CO2 concentration in the atmosphere, and to reduce global warming." More specifically, they found that predicted changes in climate, CO2 and nitrogen deposition for the year 2030 were sufficient to offset atmospheric CO2 by a sizable 41 ppm. And if likely land use changes were included in the calculations, the offset rose to a huge 76 ppm. Considering these findings, the six scientists who conducted the work, say their study suggests that "reforestation and sensible ecosystem management in industrialized regions may have larger potential for climate change mitigation [italics added, which they equate with buying time] than anticipated [italics added, which they equate with currently thought]."