Atmospheric CO2 Enrichment and Plants of Warm and Dry Regions
Donohue, R.J., Roderick, M.L., McVicar, T.R. and Farquhar, G.D. 2013. Impact of CO2 fertilization on maximum foliage cover across the globe's warm, arid environments. Geophysical Research Letters 40: 3031-3035.
Noting that "this complexity can be reduced by focusing on warm, arid environments, where water plays the dominant role in primary production and where foliage cover, plant water use, and photosynthesis are all tightly coupled," Donohue et al. say "it is in these warm and arid environments where the CO2 fertilization effect on cover should be most clearly expressed." And so it was that they went on to use gas exchange theory to predict that the 14% increase in atmospheric CO2 experienced between 1982 and 2010 should have led to a 5-10% increase in green foliage cover under these conditions, after which they went looking for evidence of this prognosticated sign of real-world CO2-induced plant growth stimulation.
Describing their findings, the four Australian researchers report that satellite observations, which were analyzed to remove the effect of variations in precipitation, showed that cover across these environments had indeed increased, and by approximately 11%. As for what it all means, Donohue et al. write in the concluding sentence of their paper's abstract that their results "confirm that the anticipated CO2 fertilization effect is occurring alongside ongoing anthropogenic perturbations to the carbon cycle and that the fertilization effect is now a significant land surface process." Or as they write in the final sentence of the body of their paper, "our results confirm that the direct biochemical impact of the rapid increase in Ca over the last 30 years on terrestrial vegetation is an influential and observable land surface process." Or to put it more directly, the greening of the Earth continues, courtesy of the ongoing rise in the air's CO2 content.
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