This seems questionable on several grounds. (1) Greenhouse growers often raise CO2 levels to ~1000 ppm to optimize growth (note this only works because all oth

This seems questionable on several grounds. (1) Greenhouse growers often raise CO2 levels to ~1000 ppm to optimize growth (note this only works because all other nutrients are supplied at ideal levels to sustain growth, however). These crops are not known to be nutritionally deficient and I'm pretty sure we'd have heard about it if they were. (2) Plants have a relatively stable ratio of nutrient requirements, with CHOPKNS CaFe Mg (mighty good) being an easy-to-remember acronym. We might be moving to a scenario in which CO2 is rarely if ever the limiting nutrient, however. Note also certain plants (C4 metabolism) have built-in CO2 concentration mechanisms, so rising CO2 might help C3 plants compete effectively. See: https://pubmed.ncbi.nlm.nih.gov/14757584/ https://pubmed.ncbi.nlm.nih.gov/14757584/ "Terrestrial plants require nutrients in similar proportions" (2004) It's more probable that there's a bit of a CO2 fertilization effect, so you get a slight increase in carbon fixation while nutrient uptake remains stable, which isn t really a 'decline' as we'd normally think of it. Basically you'd get a bit more cellulose and carbohydrate formation, but each cell still needs its normal amount of N, P, K etc. to sustain protein and DNA metabolism etc. Incidentally, the decline in insect populations mentioned in the article is largely attributable to extensive use of broad-spectrum insecticides, in particular the neonicotinoids, which are organic compounds based on the nicotine molecule with various additions (chlorine, etc.) to make them more persistent and toxic, and which were introduced in the 1980s. https://en.wikipedia.org/wiki/Neonicotinoid https://en.wikipedia.org/wiki/Neonicotinoid