In order to determine whether the overall impact of a substantial increase in the air‘s CO2 concentration on plant growth would likely be positive or negative, Lin et al. conducted a meta-analysis of pertinent data from 127 individual studies published before June 2009.
The researchers conclude, and previous meta-analyses have revealed, that warming generally increases terrestrial plant biomass, indicating enhanced terrestrial carbon uptake via plant growth and net primary productivity. Thus, we can logically expect that (1) the ongoing rise in the air‘s CO2 content will soften its own tendency to increase global temperatures, while simultaneously (2) enhancing Earth‘s terrestrial vegetation with greater growth rates and biomass production, both in the agricultural arena and throughout the planet‘s many natural ecosystems.
Lin et al. (2010) observe that most climate models predict that climate warming will increase the release of carbon dioxide from the terrestrial biosphere into the atmosphere, thus triggering positive climate-terrestrial carbon feedback which leads to a warmer climate. However, they state the stimulation of biomass accumulation and net primary productivity of terrestrial ecosystems under rising temperature may enhance carbon sequestration and attenuate the positive feedback between climate warming and the terrestrial biosphere. Lin et al. conducted this meta-analysis of scientific literature to find out which of these two views is correct.
The three scientists report that for the totality of terrestrial plants included in their analysis, warming significantly increased biomass by 12.3% and there was a significantly greater stimulation of woody (+26.7%) than herbaceous species (+5.2%). They also found the warming effects on plant biomass production did not change with mean annual precipitation or experimental duration‖ and other treatments, including CO2 enrichment, nitrogen addition, drought, and water addition, did not alter warming responses of plant biomass.
Lin, D., Xia, J., and Wan, S. 2010. Climate warming and biomass accumulation of terrestrial plants: a meta-analysis. New Phytologist 188: 187–198.