Posted on: Sunday, April 14th 2024 at 3:00 am
Is CO2 the villain it's made out to be? One researcher argues that rising CO2 levels are actually benefiting the planet by greening the biosphere
Randall Carlson's essay "The Redemption of the Beast: The Carbon Cycle and the Demonization of CO2" presents a thought-provoking perspective on the role of carbon dioxide in Earth's biosphere. Carlson argues that the demonization of CO2 as a greenhouse gas and primary driver of catastrophic climate change ignores the vital importance of CO2 to plant life. Through an extensive review of scientific literature, Carlson builds a case that rising atmospheric CO2 levels are having an overall positive effect by stimulating photosynthesis, plant growth, and a global greening of the biosphere.1
Carlson begins by providing an overview of the global carbon cycle, noting that of the approximately 400 parts per million (ppm) of CO2 currently in the atmosphere, only about 3 ppm are from anthropogenic sources like fossil fuel combustion.2 He then dives into the main theme of the essay - that CO2 is essential to plants and that hundreds of studies have consistently demonstrated significant improvements in plant growth, crop yields, and drought resistance under elevated CO2 conditions.3 For example, a 1983 study by Kimball found that a doubling of atmospheric CO2 increased agricultural yields by an average of 33%.4
The essay goes on to discuss evidence of a global greening trend in recent decades, with satellite data showing an 8% increase in vegetation cover in Australia from 1981-20065 and an increase in foliage cover across Earth's warm, arid environments in proportion to rising CO2 levels.6 Carlson cites studies attributing 70% of observed greening to the CO2 fertilization effect.7 He argues this greening is helping to mitigate the rise in atmospheric CO2 by sequestering more carbon in plant biomass.8
Carlson contends that CO2 levels were perilously low for plants during Pleistocene ice ages, falling to around 180 ppm, and that the rise in CO2 since the industrial revolution may be helping to restore optimal conditions for the biosphere.9 He suggests that if global CO2 levels were to fall by a mere 20 ppm, it could have catastrophic consequences for photosynthesis and the entire food chain.10
In conclusion, while Carlson acknowledges potential downsides to rising CO2, he argues that the demonstrable benefits to plant life are too often ignored in the prevailing narrative around climate change. He calls for a more holistic perspective that recognizes the complexity of the carbon cycle and Earth's climate system, and that weighs both the costs and benefits of CO2 as an integral part of the biosphere.
Adding support to Randall Carlson's perspective, our recent article titled "Microbial Mats: The Immortal Living Blueprint for Planetary Self-Regulation," reveals how the microbiome of the biosphere represents an ancient repository of biosynthetic pathways that help regulate planetary systems, including the exchange of gases. It may turn out that recovery from periodic natural catastrophes, and possibly also anthropogenically induced drastic changes in climate, can be attenuated through the role of microbial mats along with the plant-based mechanisms Carlson speaks of.
For more information, watch Randall Carlson's explanation in this clip from an interview he did on the subject:
References
1. Randall Carlson, "The Redemption of the Beast: The Carbon Cycle and the Demonization of CO2," unpublished manuscript, August 22, 2017, p. 1-2.
2. Ibid., p. 6-7.
3. Ibid., p. 10-25.
4. B. A. Kimball, "Carbon Dioxide and Agricultural Yield: An Assemblage and Analysis of 430 Prior Observations," Agronomy Journal 75 (1983): 779-788, quoted in Carlson, "The Redemption of the Beast," p. 17.
5. Randall J. Donohue, Tim R. McVicar, and Michael L. Roderick, "Climate-related trends in Australian vegetation cover as inferred from satellite observations, 1981-2006," Global Change Biology 15 (2009): 1025-1039, cited in Carlson, "The Redemption of the Beast," p. 45.
6. Randall J. Donohue et al., "Impact of CO2 fertilization on maximum foliage cover across the globe's warm, arid environments," Geophysical Research Letters 40 (2013): 3031-3035, cited in Carlson, "The Redemption of the Beast," p. 46.
7. Zaichun Zhu et al., "Greening of the Earth and its drivers," Nature Climate Change 6 (2016): 791-796, cited in Carlson, "The Redemption of the Beast," p. 48-49.
8. Carlson, "The Redemption of the Beast," p. 39-40.
9. Ibid., p. 53-59.
10. Ibid., p. 58.
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