| I wouldn't disagree with the high mortality from pollution toxins. I've never looked closely, but also seems common sense. As for how much greening benefits offset costs, I was mildly frustrated by the downvoting :) and went researching on the economic effects in particular. The only study I can find on CO₂ fertilization is recent and stunning: "we apply the CO₂ fertilization effect... backwards to 1940, and, assuming no other limiting factors, find that CO₂ was the dominant driver of [American agriculture] yield growth" https://www.nber.org/system/files/working_papers/w29320/w293... As they note, the extrapolation is from a study period of 2014-2020, but it's expected they have underestimated the prior role of CO₂ fertilization, as CO₂ response becomes saturated as levels rise and that's not represented in their model. This is 2021 research funded by DOE & USDA, run by NBER, with PIs from Harvard and Columbia who are well cited within their field of environmental economics. Given the pedigree and that conclusion, this should be front-page news in science mags at least. I couldn't find any reporting on it except for Epoch Times (https://www.theepochtimes.com/science/nasa-satellite-data-su...), which gets an eye-roll from me, but guess they got this one :) I read the full thing. It's great. Crosses high-resolution satellite CO₂ anomaly observations (NASA OCO-2) with crop yield records, wind modeling, sensitivity testing on non-ag land and the result is broadly repeated: +1ppm CO₂ -> +~0.5-1% yield. CO₂ levels went from ~310-410ppm in that period. If true, it seems at odds with the normal account that gave nitrogen fertilization the lead role for increasing crop yields this past century and lifting most of the world's population out of regular food insecurity, and the growth of our population into billions. Seems more likely both were necessary. It also makes sense, as C3 plants (e.g. soy, wheat and most plants besides hot/dry grasses) respond positively to CO₂ partial-pressures up to 800-1000ppm. C4 low-CO₂ adapted corn also fertilizes, just to a lesser extent. The authors also note the negative effects of heat stress, but this wouldn't have been as significant in the extrapolation period. From Epoch Times: “The paper’s first author, Taylor, said: 'We reiterate that climate change will have a large negative impact on agriculture in aggregate, especially in places exposed to extreme heat. And higher CO2 may even lower food nutrition. But the countervailing fertilization effect should also be taken into account.'” |