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On a quick read of the paper (thanks for the link) I was bothered that I found no mention of the fact that the per-acre yield also goes up with increased CO2.
by nkurz 7y ago
On a quick read of the paper (thanks for the link) I was bothered that I found no mention of the fact that the per-acre yield also goes up with increased CO2. Each grain of rice (likely) has slightly less nutrients, but more grains of rice are produced in a given field. From other articles I found, it looks like the yield is expected to increase by about 13%. Omitting any mention of this feels like a political decision.
It's also worth noting that the paper doesn't really try to prove that nutrition levels will drop, but instead concentrates on showing that if nutrition levels in rice drop that more people may experience deficiencies. In particular, it cites a paper that actually did the experiment, and found no decrease in nutrients other than Nitrogen: http://sci-hub.tw/https://doi.org/10.1016/j.fcr.2004.01.004 http://sci-hub.tw/https://doi.org/10.1016/j.fcr.2004.01.004. This experiment implies that it's at least possible to grow rice under high CO2 levels without experiencing the drop.
I also thought the mitigation section was odd. It points out that only a few countries currently fortify rice with Vitamin B. It notes that fortification is inexpensive and effective, although it would require a major effort to begin doing so in other countries. The paper also shows that nutrient deficiency is already a large problem, and that increase caused by a decrease in foliate levels in rice would only be 1.5%. Maybe a better conclusion would be that these countries should really be fortifying their rice?
I didn't think it was a bad paper, and it wasn't "bunk". I agree that knowing what sort of changes to expect from an increased CO2 level is a good thing. But it did seem like it might be pushing an agenda more than just trying to lay out the scientific conclusions.
- chrisco255 7y agoIt's especially weird since crop yields are up like 30-40% since 1988. Not that rice is especially nutritious in the first place. It's basically a bunch of carbs with miniscule levels of vitamins.
- sedachv 7y agoYou need read up on agriculture basics before posting junk comments. > From other articles I found, it looks like the yield is expected to increase by about 13%. Omitting any mention of this feels like a political decision. That is because CO2 enrichment as a way to increase yields is decades old common knowledge and a widespread practice in greenhouses. Just because you did not know that, does not mean there is a conspiracy here. > It's also worth noting that the paper doesn't really try to prove that nutrition levels will drop Because nutrient density decrease is something that has already happened: https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511 https://www.politico.com/agenda/story/2017/09/13/food-nutrie...
- esyir 7y agoThe issue here is the notoriously shit science media with no room for nuance. This one goes in along with "SCIENTISTS CURE CANCER" in which you get potentially interesting findings that get blown horribly out of proportion by whatever rag that decides to post it, often with a political spin to boot.
- kaitai 7y agoWhile... blunt... your comment is exactly right. I don't mention the definition of degree of polynomial when I write an algebraic geometry paper. The knowledge that CO2 increases yields is universal among scientists reading this paper.
- nkurz 7y agoPerhaps obviously, I disagree. It's not that every paper has to mention everything that's obvious, but my point was that the choice of how to frame the problem can be a political decision. There was no attempt to explain why micronutrient per serving of rice was the right metric, and I think using it can be misleading if the amount of rice grown changes for the same reason that the nutrients are dropping. And while "everyone knows" that yields will increase, there is disagreement on whether the increase in yield is dependent or independent of the change in nutritional value. By the way, I liked your comment elsewhere in this thread about eating plain rice. But rather than lamenting that all the references are behind paywalls, I personally think it's better just to give the DOI's and a link to http://sci-hub.tw http://sci-hub.tw. Or even better yet, just link to the papers, profits of publishers be damned. The world is better off when more people read the actual science.