Higher CO2 Levels May Be Good for Plants

I found this interesting and thought some of you might also.
From Breitbart News:
[/FONT]http://www.breitbart.com/article.php?id=080708124018.8nen8ib9&show_article=1

"The dangerous rise in greenhouse gas in the atmosphere may be troubling scientists and world leaders but it could prove to be a boon for plants, German researchers said Tuesday.

Increasing exposure to carbon dioxide appears to boost crop yields, Hans-Joachim Weigel of the Johann Heinrich von Thuenen Institute for rural areas, forestry and fisheries in the central city of Brunswick told AFP. “Output increased by about 10 percent for barley, beets and wheat” when the plants were subjected to higher levels of carbon dioxide, Weigel said. …"

This works only for cases where CO2 is the limiting factor. If there’s an excess of nitrogen, phosphorus, iron, etc., you will see larger yields.

But that’s not usually the case. For example, higher CO2 levels don’t do much for phytoplankton (small plants in the sea) unless one adds iron (which happens to be the limiting factor there). Do that, and you get huge blooms of plant life.

The article didn’t link the original study, nor say anything about CO2 as a limiting factor. As a gardener, I have heard that speaking to plants helps them grow, and I also heard or read this explained as the CO2 from a person’s breath when talking to them being what helped the plant.

The article did not address phytoplankton; it discussed traditional food crops such as barley and wheat that grow on land. It also didn’t say anything about different levels of nitrogen, phosphorus or iron, which I assumed would be a constant for a scientific experiment studying the effects of increased CO2 on crops growing on land.

No, in some plants that aren’t C4 or CAM plants, higher temperatures produced by global warming will lead to increased photorespiration (as at high termperatures O[sub]2[/sub] will become more soluble relative to CO[sub]2[/sub] so rubisco will fix more oxygen than carbon dioxide)

I don’t know what you mean by “C4 or CAM plants” but the study in this article did not look at increased temperature. It specifically states, "He (Weigel, the researcher) said the next step in the study would be to evaluate the effect of higher temperatures on plant growth – which scientists cite as another consequence of higher CO2 emission in the atmosphere. "

I learned this in high school 60 years ago. Through the process of photosynthesis, plants take in CO2 and produce O2 into the atomosphere. It stands to reason that increased levels of CO2 would be beneficial to plants, just like increased fertilizer (if not overdone).

I learned this in high school 60 years ago. Through the process of photosynthesis, plants take in CO2 and produce O2 into the atomosphere. It stands to reason that increased levels of CO2 would be beneficial to plants, just like increased fertilizer (if not overdone).

This is correct, if CO2 is the nutrient that is most lacking. But it usually isn’t.

If, for example, nitrogen is lacking, adding CO2 won’t help.

Well, at least there is a good side to the higher carbon dioxide emissions. :slight_smile:

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