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Good for plants, but not necessarily for humans. Human mental performance seems to reduce at higher CO2 levels, which makes sense as humans (by any definition..

Good for plants, but not necessarily for humans. Human mental performance seems to reduce at higher CO2 levels, which makes sense as humans (by any definition... behaviorally modern humans ~50,000 years ago, anatomically modern humans 300,000 years ago, the overall genus homo within about 2 million years) have never experienced CO2 levels near the current level, let alone what they may be by the end of the century. Perhaps CO2 levels will be higher than ever experienced by great apes since we first evolved 14 million years ago: https://earth.org/data_visualization/a-brief-history-of-co2/ https://earth.org/data_visualization/a-brief-history-of-co2/

morpheos137 5y ago
Do you got a source for the idea that human mental preformance suffers in the the hundred ppm CO2 range? I don't see how it would since the body has homeostatic mechanisms. CO2 has only increased by several hundred ppm since the industrial revolution. Maybe you are confusing CO2 with CO which has completely different biochemistry (it binds more efficiently with hemoglobin than oxygen and or does not release as easily once bound).
- Robotbeat 5y ago
  No, I'm not confusing CO for CO2. Yes, I do have sources that human mental performance suffers at elevated CO2 levels (800-1000ppm, not uncommon in buildings... but could be the CO2 level outdoors and even if it's not quite that high, it'll be harder and harder to keep building CO2 levels below that as external CO2 levels increase). https://www.nature.com/articles/s41370-018-0055-8 https://www.nature.com/articles/s41370-018-0055-8 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037 Current levels aren't really problematic except in stuffy buildings. But if we don't stop changing the chemistry of the atmosphere, it becomes a problem.
  - morpheos137 5y ago
    It would be interesting if the study could be duplicated. More importantly it does not seem to distinguish between the acute effect of a sudden increase in CO2 in an experimental setting and the chronic effect of gradually rising ambient rates over the span of years. It stands to reason that the body would adapt to higher CO2 levels over longer time ranges vs. just injecting a sudden pulse of 2500 ppm into a closed chamber.
    - Robotbeat 5y ago
      Well, good news! We’re conducting a planetwide, n = 8 billion, study on this topic right now! We don’t have a control group, though, except maybe a handful of rich folk who can afford to scrub CO2 from their penthouses.

morpheos137 5y ago

Do you got a source for the idea that human mental preformance suffers in the the hundred ppm CO2 range? I don't see how it would since the body has homeostatic mechanisms. CO2 has only increased by several hundred ppm since the industrial revolution. Maybe you are confusing CO2 with CO which has completely different biochemistry (it binds more efficiently with hemoglobin than oxygen and or does not release as easily once bound).

Robotbeat 5y ago
No, I'm not confusing CO for CO2. Yes, I do have sources that human mental performance suffers at elevated CO2 levels (800-1000ppm, not uncommon in buildings... but could be the CO2 level outdoors and even if it's not quite that high, it'll be harder and harder to keep building CO2 levels below that as external CO2 levels increase). https://www.nature.com/articles/s41370-018-0055-8 https://www.nature.com/articles/s41370-018-0055-8 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037 Current levels aren't really problematic except in stuffy buildings. But if we don't stop changing the chemistry of the atmosphere, it becomes a problem.
- morpheos137 5y ago
  It would be interesting if the study could be duplicated. More importantly it does not seem to distinguish between the acute effect of a sudden increase in CO2 in an experimental setting and the chronic effect of gradually rising ambient rates over the span of years. It stands to reason that the body would adapt to higher CO2 levels over longer time ranges vs. just injecting a sudden pulse of 2500 ppm into a closed chamber.
  - Robotbeat 5y ago
    Well, good news! We’re conducting a planetwide, n = 8 billion, study on this topic right now! We don’t have a control group, though, except maybe a handful of rich folk who can afford to scrub CO2 from their penthouses.