How Green Is Thy Planet?

Deciding which is the greatest single blunder of the climatistas is a difficult contest, because you have so much to choose from. Aside from their dreadful leading spokesspecies (Al Gore, Bill McKibben, Robert F. Kennedy Jr., Leo di Caprio—Green Weenies all), perhaps the stupidest move was the decision to call carbon dioxide—the compound that humans exhale to the tune of about 800 lbs per person per year—a “pollutant.” Sure, it’s a warming agent according to theory, but to call it a “pollutant” comparable to carbon monoxide is ludicrous.

Because that “carbon pollution,” as Gore likes to call it in his uniquely sonorous voice that instantly makes you want to disbelieve him, is what plants and trees eat for dinner. Which brings me to this story reported at Science Daily today:

Enhanced levels of carbon dioxide are likely cause of global dryland greening, study says

Enhanced levels of atmospheric carbon dioxide are a likely key driver of global dryland greening, according to a paper published in the journal Scientific Reports.

The positive trend in vegetation greenness has been observed through satellite images, but the reasons for it had been unclear.

After analyzing 45 studies from eight countries, Lixin Wang, assistant professor of earth sciences in the School of Science at Indiana University-Purdue University Indianapolis, and a Ph.D. student in Wang’s group, Xuefei Lu, concluded the greening likely stems from the impact of rising levels of atmospheric carbon dioxide on plant water savings and consequent increases in available soil water.

“We know from satellite observations that vegetation is greener than it was in the past,” Wang said. “We now understand why that’s occurring, but we don’t necessarily know if that’s a good thing or not.” . . .

Lu and Wang considered other potential drivers that could have caused the greening, including increased rainfall and changes in land-management practices. But only carbon dioxide provided a global explanation for changes to dryland vegetation. . .

The researchers believe the greening is a response to higher atmospheric carbon dioxide inducing decreases in plant stomatal conductance — the measure of the rate of passage of carbon dioxide entering, or water vapor exiting, through the stomata of a leaf — and increases in soil water, thus enhancing vegetation growth.

The researchers examined the sensitivity of soil water change to varying levels of carbon dioxide, finding a significant positive change in soil water along the carbon dioxide enrichment gradient. . .

Imagine that: higher levels of carbon dioxide cause plants to grow more robustly and with less water. A “pollutant” with benefits! It’s something a 4th grader might predict the first day of instruction about photosynthesis. This is not a new story, of course. The so-called “deniers” have been making this observation, and pointing to data sets and studies, for a long while now. Still, nice to see it breaking out into the “mainstream” literature.

The study does of course end with this boilerplate caution:

Going forward, Wang said, the positive effect of carbon dioxide-induced water savings may eventually be offset by the negative effect of carbon dioxide-induced temperature increases when the temperature increase crosses a certain threshold.

But that’s required if you want to get something into print.