[ExI] WSJ Article: "In Defense of CO2"

Fri May 10 07:19:19 UTC 2013

Yes! Knowing that more CO2 in the atmosphere means less water need for
plants - is just essential. CO2 IS a blessing, in fact!

On Thu, May 9, 2013 at 11:27 PM, Kevin G Haskell <kgh1kgh2 at gmail.com> wrote:

> "In Defense of Carbon Dioxide" - WSJ
>
> "By HARRISON H. SCHMITT AND WILLIAM HAPPER
>
> Of all of the world's chemical compounds, none has a worse reputation than
> carbon dioxide. Thanks to the single-minded demonization of this natural
> and essential atmospheric gas by advocates of government control of energy
> production, the conventional wisdom about carbon dioxide is that it is a
> dangerous pollutant. That's simply not the case. Contrary to what some
> would have us believe, increased carbon dioxide in the atmosphere will
> benefit the increasing population on the planet by increasing agricultural
> productivity.
>
> The cessation of observed global warming for the past decade or so has
> shown how exaggerated NASA's and most other computer predictions of
> human-caused warming have been—and how little correlation warming has with
> concentrations of atmospheric carbon dioxide. As many scientists have
> pointed out, variations in global temperature correlate much better with
> solar activity and with complicated cycles of the oceans and atmosphere.
> There isn't the slightest evidence that more carbon dioxide has caused more
> extreme weather.
>
> The current levels of carbon dioxide in the earth's atmosphere,
> approaching 400 parts per million, are low by the standards of geological
> and plant evolutionary history. Levels were 3,000 ppm, or more, until the
> Paleogene period (beginning about 65 million years ago). For most plants,
> and for the animals and humans that use them, more carbon dioxide, far from
> being a "pollutant" in need of reduction, would be a benefit. This is
> already widely recognized by operators of commercial greenhouses, who
> artificially increase the carbon dioxide levels to 1,000 ppm or more to
> improve the growth and quality of their plants.
>
> Using energy from sunlight—together with the catalytic action of an
> ancient enzyme called rubisco, the most abundant protein on earth—plants
> convert carbon dioxide from the air into carbohydrates and other useful
> molecules. Rubisco catalyzes the attachment of a carbon-dioxide molecule to
> another five-carbon molecule to make two three-carbon molecules, which are
> subsequently converted into carbohydrates. (Since the useful product from
> the carbon dioxide capture consists of three-carbon molecules, plants that
> use this simple process are called C3 plants.) C3 plants, such as wheat,
> rice, soybeans, cotton and many forage crops, evolved when there was much
> more carbon dioxide in the atmosphere than today. So these agricultural
> staples are actually undernourished in carbon dioxide relative to their
> original design.
>
> At the current low levels of atmospheric carbon dioxide, rubisco in C3
> plants can be fooled into substituting oxygen molecules for carbon-dioxide
> molecules. But this substitution reduces the efficiency of photosynthesis,
> especially at high temperatures. To get around the problem, a small number
> of plants have evolved a way to enrich the carbon-dioxide concentration
> around the rubisco enzyme, and to suppress the oxygen concentration. Called
> C4 plants because they utilize a molecule with four carbons, plants that
> use this evolutionary trick include sugar cane, corn and other tropical
> plants.
>
> Although C4 plants evolved to cope with low levels of carbon dioxide, the
> workaround comes at a price, since it takes additional chemical energy.
> With high levels of carbon dioxide in the atmosphere, C4 plants are not as
> productive as C3 plants, which do not have the overhead costs of the
> carbon-dioxide enrichment system.
>
> That's hardly all that goes into making the case for the benefits of
> carbon dioxide. Right now, at our current low levels of carbon dioxide,
> plants are paying a heavy price in water usage. Whether plants are C3 or
> C4, the way they get carbon dioxide from the air is the same: The plant
> leaves have little holes, or stomata, through which carbon dioxide
> molecules can diffuse into the moist interior for use in the plant's
> photosynthetic cycles.
>
> The density of water molecules within the leaf is typically 60 times
> greater than the density of carbon dioxide in the air, and the diffusion
> rate of the water molecule is greater than that of the carbon-dioxide
> molecule.
>
> So depending on the relative humidity and temperature, 100 or more water
> molecules diffuse out of the leaf for every molecule of carbon dioxide that
> diffuses in. And not every carbon-dioxide molecule that diffuses into a
> leaf gets incorporated into a carbohydrate. As a result, plants require
> many hundreds of grams of water to produce one gram of plant biomass,
> largely carbohydrate.
>
> Driven by the need to conserve water, plants produce fewer stomata
> openings in their leaves when there is more carbon dioxide in the air. This
> decreases the amount of water that the plant is forced to transpire and
> allows the plant to withstand dry conditions better.
>
> Crop yields in recent dry years were less affected by drought than crops
> of the dust-bowl droughts of the 1930s, when there was less carbon dioxide.
> Nowadays, in an age of rising population and scarcities of food and water
> in some regions, it's a wonder that humanitarians aren't clamoring for more
> atmospheric carbon dioxide. Instead, some are denouncing it.
>
> We know that carbon dioxide has been a much larger fraction of the earth's
> atmosphere than it is today, and the geological record shows that life
> flourished on land and in the oceans during those times. The incredible
> list of supposed horrors that increasing carbon dioxide will bring the
> world is pure belief disguised as science.
>
> Mr. Schmitt, an adjunct professor of engineering at the University of
> Wisconsin-Madison, was an Apollo 17 astronaut and a former U.S. senator
> from New Mexico. Mr. Happer is a professor of physics at Princeton
> University and a former director of the office of energy research at the
> U.S. Department of Energy.
>
> http://online.wsj.com/article/SB10001424127887323528404578452
> 483656067190.html?mod=WSJ_Opinion_LEADTop
>
> --
>  * Tweet me on Twitter! - @*KevinGHaskell
>
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