Synergy of Rising Nitrogen Depositions and Atmospheric CO2 on Land Carbon Uptake Moderately Offsets Global Warming

Increased carbon uptake of land in response to elevated atmospheric CO2 concentration and nitrogen deposition could slow down the rate of CO2 increase and facilitate climate change mitigation. Using a coupled model of climate, ocean, and land biogeochemistry, we show that atmospheric nitrogen deposition and atmospheric CO2 have a strong synergistic effect on the carbon uptake of land. Out best estimate of the global carbon uptake in 1990th is 1.34 PgC/yr. The synergistic effect could explain 47% of this global carbon uptake, which is higher than either the effect of increasing nitrogen deposition (29%) or CO2 fertilization (24%). By 2030 rising carbon uptake on land has a potential to reduce atmospheric CO2 concentration by about 38 ppm out of which 16 ppm reduction would come from the synergetic response of land to the CO2 and nitrogen fertilization effects. The strength of the synergy depends largely on the co-occurrence of high nitrogen deposition regions with non-agricultural ecosystems. Our study suggests that reforestation and sensible ecosystem management in industrialized regions may have larger potential for climate change mitigation than anticipated.

CHURKINA Galina;  BROVKIN Victor;  VON BLOH Werner;  TRUSILOVA Kristina;  DENTENER Franciscus;  JUNG Martin; 

2009-11-30

AMER GEOPHYSICAL UNION

JRC44928

0886-6236,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC44928,   

10.1029/2008GB003291,