“But Life”

This square comprises appeals to the critical importance of carbon dioxide.

It would be hard to appeal both to the fact that CO2 is life and that it’s a trace gas. Yet they are often seen hand in hand, or one after the other. Pointing out the contradiction helps.


World growing greener with increased carbon. Thirty years of satellite evidence. Forests growing faster and thicker.


Of 118 known elements, carbon: bonds with the most other elements; is the 2nd most abundant in the human body; is the 4th most abundant in the universe.


Objections and Replies

Decarbonisation. To decarbonise would be to kill
☞ Water is critical, yet you can drown in it. Oxygen can start fire, which kill. Vitamin A in too high dosage can kill. The list goes on and on.

Essential. CO2 is essential to lif
☞ We can also add methane, sulfur, and water to recreate the Archean Eon. Without oxygen, human babies are having a tough time.

Fertilization. More carbon dioxide means more fertilization
☞ You can have positive and negative things going at once, and it’s the net balance that matters.

Greening. The world is greening nowadays, and that’s good
☞ It’s indeed good that you accept that it is warming. It’s also important to realize that CO2 benefits plants only up to a point, and it’s just one factor.

Greenhouse. Gardeners have long added CO2 to greenhouses
☞ True, up to a point. Some type of plants (C3) profit from more, others (C4) less so.

Grow. Plants don’t grow without CO2. They don’t grow MORE without MORE
☞ I doubt that photosynthesis proceeds by modus tollens. From the absence of CO2 you can’t infer anything regarding the presence of CO2.

Life goes on.
☞ See #ButAccelerate.

Lower. If you lowered CO2 levels by 50% life on earth would cease to exist
☞ There was Life on Earth at 200 ppm. Humans would suffer if they lowered iron levels by 50%. Should we ingest as much iron as we can?

Optimal. The critical question is the optimal temperature the Earth
☞ If you believe so, then show your homework. The rate of change matters, and the biosphere is warming more rapidly than in hundreds of thousands of years and perhaps many millions of years.

Plant Food. CO2 is plant food
☞ That’d be sugar {1}. The overall Calvin Cycle is fairly complex.

Pollution. CO2 cannot be pollution, as it’s what you exhale—
Pollution is best considered an activity of man, which directly or indirectly results in the addition to water, air or soil, of matter or energy which has a deleterious effect on living organisms or structures it is desirable to preserve, or which reduces the quality of water, air or soil for any subsequent use [V.S. Russell, 1974-07].


{1} I owe this point to Bob Droege.


2019-09; Earth Stopped Getting Greener 20 Years Ago.

2018-01; Ask the Experts: Does Rising CO2 Benefit Plants?

2010; Effects of Rising Atmospheric Concentrations of Carbon Dioxide on Plants;


2021-02; Where are Global Vegetation Greening and Browning Trends Significant? https://doi.org/10.1029/2020GL091496

2019-12; Characteristics, drivers and feedbacks of global greening.

2018-12; Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction. 10.1126/science.aat1327

1974-07; Pollution: Concept and definition; https://doi.org/10.1016/0006-3207(74)90060-3