Thursday, March 13, 2014

Review finds CO2 fertilization has increased forest productivity and resistance to drought

A new paper from SPPI and CO2 Science reviews the scientific literature on biospheric productivity in South America and finds robust evidence that the increase in CO2 fertilization has resulted in ever-increasing forest production. In addition, plants exposed to increased CO2 have been found to lose less water to transpiration, and thus are better able to withstand drought.

[Illustrations, footnotes and references available in PDF version]
How will the terrestrial vegetation of South America respond to global warming and atmospheric CO2 enrichment? Climate alarmists suggest there will be widespread declines in both ecosystem size and productivity. But are these predictions correct? Given the fact that over the past century the Earth has experienced what alarmists refer to as unprecedented rises in both atmospheric temperature and CO2 concentration relative to the past two thousand years and several million years, respectively, plants should already be responding to the changes in these two environmental parameters. And what has that response been? In this summary we consider this question as it applies to locations in South America.
CO2 fertilization effects strongly increased recent Net Primary Production trends in regional totals.
Such a finding is especially interesting, because for most of the past century it was believed that old-growth forests, such as those of Amazonia, should be close to dynamic equilibrium. Just the opposite, however, has been repeatedly observed by several different groups of researchers over the past two decades.

Plants exposed to elevated CO2 concentrations are likely to lose less water via transpiration.

As a result, at higher CO2 concentrations, plants can better cope under conditions of drought, thereby vastly improving their productivity and growth as opposed to conditions experienced under lower CO2.

In light of the voluminous and undeniable real-world observations reported in the studies described above, it must be acknowledged that where tropical forests have not been decimated by the direct destructive actions of man, such as the felling and burning of trees, forest productivity has been growing ever greater with the passing of time, rising hand-in-hand with the increasing CO2 content of the air; and it has been doing so in spite of all concomitant changes in atmospheric, soil, and water chemistry, as well as "dreaded" 20th-century global warming, which is claimed by climate alarmists to have been unprecedented over the past two millennia. Real-world evidence also suggests that the anthropogenic-induced increase in the air's CO2 content is primarily responsible for this beneficent state of affairs, which further suggests that if humanity will but cease its direct physical assaults upon Earth's tropical forests, there is nothing to fear about their future well-being but ill-founded fear itself.

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