Increased terrestrial net primary production in Africa in response to climate and other environmental changes
Africa represents one of the most vulnerable regions to climate change, but relatively less attention has been given to understand the response of terrestrial net primary production (NPP) to climate change and other environmental factors. Here we used an integrated ecosystem model (the Dynamic Land Ecosystem Model -DLEM) to simulate the dynamic variations in terrestrial (NPP) of African ecosystems during 1980-2009 in response to climate and other environmental drivers.
We estimate a terrestrial NPP of about 10.22 (8.9 – 11.3) Pg C yr-1 during 1980-2009. Our results show that precipitation variability had a significant effect on terrestrial NPP, explaining 74% of the NPP inter-annual variations. Over the 30-year period, Africa experienced a total increase in NPP of 0.9 Pg C under the influence of climate change, elevated atmospheric CO2 concentration, and nitrogen deposition. Our further analyses show that wet and dry climatic conditions substantially alter the magnitude of NPP in some particular years. The dry year of 1983 resulted in the decline in terrestrial NPP by 13% compared to the 30-year mean. Across regions, central Africa dominated by tropical forests was the most productive regions that accounted for 50% of the carbon sequestered as NPP. Our results indicate that warmer and wetter climatic conditions together with elevated atmospheric CO2 concentration and nitrogen deposition have resulted in a significant increase in terrestrial NPP during 1980-2009 with the largest contribution from tropical forests.