Another bad paper in Nature

Increasing CO2 threatens human nutrition” boldly proclaims a new paper from last week in Nature by Samuel Myers of Harvard and 19 co-authors (press release here). I don’t have time for this, but something needs to be said and if I don’t do it, I betcha nobody will.

Papers can be bad for various reasons, obviously. Logically enough, this is most often due to poor methodology. But it can also be because the science is more or less OK, as far as it goes, but the importance of the principal claim(s) of the paper does/do not really follow from the study’s actual findings. By “principal claim” I mean the one or two main points most emphasized, perhaps in the concluding paragraph, or the abstract, or even just the title itself, like in this case. This paper has both problems, but especially the latter.

Nature publishes a lot of bad science frankly, but I’m surprised more than normally at the audacity of this one. This thing shouldn’t have been published in Nature in the first place. I get the strong impression that Nature and other glamour journals are counting on people just reading the title and skimming the paper, without any real critical evaluation. Why? Because if you have any basic sense of the issues and read this paper, there’s no way you can accept that title as stated based on the study performed, even if the paper’s methodology were entirely sound, which it is not. Who exactly do they think is reading these papers, and indeed, who is reading them? Not skimming, I mean really reading closely. Well we have no idea, because critical, in-depth commentary on papers is rare indeed.

Think about the claim in the title for just a second; better yet, try to imagine that you’d never heard about carbon dioxide in relation to climate change. This is a very major claim, and a fairly novel one, so we should naturally ask questions like “How exactly, by what mechanism?”, “How much?”, “Under what kind of time frame?”, “What portion of humans are threatened?”, “What aspect of nutrition, exactly”, and any number of similar, critical questions.

I won’t even get into the plant physiology and/or genetics involved here (at least not now), but undoubtedly many issues could be raised thereon, because the effects of elevated CO2 on plant physiology and productivity is a very much unsettled topic with conflicting evidence from various types of studies, molecular to system-level. The lead author of the paper is not a plant biologist as far as I can tell. It is not clear to me whether or not the lead author is a plant physiologist. But the essence of the paper is plant physiology, not human nutrition, and moreover, it’s a meta-analysis combining some of their data and some from previous studies. And meta-analyses are frequently invitations to analytical problems because of the different methods, assumptions and purposes between the various studies comprising them. I’ll keep this simple, but it would still help if you looked it over–the tables and figures (in both the paper and the supplement) are freely available via the above link, as is the abstract. You can also of course request the full paper from the lead author, as I did.

Their basic meta-analysis finding is in fact very modest: that zinc, iron and/or total protein will decline by somewhere between 0 and 10 percent in the edible portion of multiple cultivars of three major cereal grain (wheat, rice, corn), two legume (soybean and garden pea), and one sugar/ethanol (sorghum) crops, in response to an increase in [CO2] to levels approximately double (i.e. 550-580 ppm) that of pre-industrial (~278-280 ppm). In most cases these declines are in the 4 to 8 percent range and in some cases there are in fact increases, not decreases.

The key communication problem is the way they expand this rather minor finding into a major, sweeping generalization, and the key methodological issue is the apparent failure to take into account one of the simplest of potentially complicating factors. Specifically, if you decrease the percentage composition of some component x (here, nutrient concentrations) in some material y (grain and seed), but you also increase the total amount of y, then even if the concentration of x has in fact decreased…well so what, you have a partially to completely compensating mechanism via the increase in total seed mass. That’s not a difficult concept and you’ve got twenty authors here–and not one of them (nor any of the three reviewers) can spot this issue? That should be one of the very first things you should think about, especially given that evidence for biomass increases with increased atmospheric [CO2] in C3 plants (e.g. wheat, rice, soy), is abundant.

I could get into at least 5 to 10 more points but will keep it to just three here: (1) How sure are they of the sources from which they get their claim that 2.3 billion people in the world suffer zinc and/or iron deficiences, putatively causing the loss of “63 million life-years annually”, (2) Even if they are right about these deficiencies, and their plant physiology work is robust and dependable, how can they assume this will in fact necessarily “threaten human nutrition”–do they think there are no other possible solutions to zinc and iron deficiencies in those claimed 2.3 billion people that are already deficient? (ever heard of supplements for example?), and (3) Their computations of how long it will take to reach ~ 560 to 580 ppm CO2 are off. We’re at about a 2 ppm/yr increase rate now (generously), there is no definite evidence for a strongly positive carbon cycle feedback, and so that rate equates to something like 80-90 years to 560-580 ppm, not their stated 40-70 years. They’re exaggerating, and then Harvard press release amplifies this by using the lower end of that range, claiming that we’ll be there by 2050. Two minutes for hooking and another two for embellishment, rules the referee.

And if you want to know the growing conditions used in the various FACE experiments involved, well they’re not summarized–you’re instead directed to five other papers scattered throughout the literature to get that information. How many people do you think are going to do that?

This paper should have been titled something like “Doubled CO2 may decrease zinc, iron and protein concentrations in several major crop species” and been submitted to Crop Science or Plant Physiology or similar journals. And, if an increase in total grain amount did in fact accompany the decline in nutrient concentrations, then the title should have reflected this reality.

My default position toward Nature (and PNAS for that matter), at least for environmental science papers (including climate science and ecology), has shifted from innocent until proven guilty, to roughly the opposite. I just don’t believe what they claim until I’ve read the paper involved closely, and since I don’t have time to do that, that means I basically don’t accept what they claim. I’ve just seen too much bad science and I don’t trust them to be fully objective and place scientific veracity over hype and headline. Sorry.

p.s. Please don’t just take my word on all this–look at the available tables and graphs at the Nature website and make your own decision, and better yet, read the paper.

Advertisements

31 thoughts on “Another bad paper in Nature

  1. Who was it who said “Just because it’s in Nature doesn’t automatically mean it’s wrong”?
    I think it was Carl Wunsch.

    Have you thought of joining the advisory board of GWPF?

  2. “Hockey Schtick” submitted a comment and I approved it, but neither it, nor my reply, will appear, and I have no idea why.

    Hockey Schtick: “As a suggestion, you may want to change the name of your blog from “Ecologically Orientated” to “Ecologically Oriented” since “orientated’ is not a word and detracts from your message. Thanks for your posts.”

    Me: I did that on purpose actually, just being in a weird mood the day I set the thing up. Just picked a slightly wrong blog name, grabbed a picture of the dog, and off I went.

    • That was my first reaction to the word too, but then I looked it up and apparently it’s one of the odd English English things; kind of like favourite.

      Glad to find your blog, Jim (thru Bishop Hill). The really poor science in the climate area is very dispiriting; and it parallels the poor nutritional science that has led us quite astray there over the last half century or so. But the ideologues continue their fight against the evidence regardless of the established facts.

    • Human health and nutrition is one of the most important topics that scientists (and others) can address, because it directly and very strongly affects human well-being in many ways. Obviously, there are many many factors that go into human nutrition, many many factors indeed. It burns me when I see topics like this, which are mostly not related to atmospheric [CO2] issues, and for which we have very strong and definite evidence of other much more important factors, get hijacked just because CO2 is the hot, go-to topic right now. This is not acceptable; it diverts everyone from a true and balanced understanding of the problem, and hence, its solution. These authors make no attempt whatsoever to place these small Zn and Fe decreases over multiple decades in the context of larger issues. What’s the point of having 20 authors if you’re not going to engage in a wide-ranging discussion and place the findings in context?

  3. very nicely summarized. succint. “climate change causes (enter your disaster here), all children will die. cue hype and dismay. alert press. move on to next grant/funding. repeat.

  4. … Who exactly do they think is reading these papers, and indeed, who is reading them?..

    They are published so that they can be cited as absolute truth by activists who are campaigning for environmental legislation. You can see exactly the same thing happening with the EPA in the US – remember their Polar Bear argument for specifying CO2 as a pollutant? Look at the papers they cited – all papers with alarmist titles and conclusions, but ones where the data did not justify this at all….

    • You put your finger on a big problem. A lot of non-scientists think publications in Nature and such are like an authoritative, or even final, word or something. Unfortunately, a lot of scientists are more than willing to play along on this, and indeed, a lot of them believe it themselves.

      Lots of smoke and mirrors involved, and much of the public has no idea. But then, they really shouldn’t have to have doubts about the quality of the science being put out by these journals, so I don’t blame them. In fact, I used to believe the same thing.

  5. Not wanting to nitpick, but as an Englishman I can attest to the validity of the word “orientated”. Still, as a nation who cannot decide even how to pronounce certain words consistently (e.g. a sporting “defense” versus the Secretary of Defense – also, you can’t spell defence properly) I guess I can let you off. 😉

    Now, time for my meds…

  6. To discover that “orientated” isn’t a word would come as a surprise to millions of British English speakers, also a number of lexicographers. Google it and read about the long controversy over “oriented” and “orientated”.

    Fact is, whether a word is regarded as valid is determined–in the English language at any rate–by usage. It’s not like French, where correct words have to receive official imprimatur from the Académie française (in no small part, incidentally, owing its existence to the chauvinistic desire to prevent French becoming sullied by the absorption of English words).

    Words are what people actually use, and accepted usage varies in time and according to location.

    • I understand that French was not universally spoken throughout France until the late 19th Century, so the obsession with defending the ‘correct’ language was very much about control of the ‘provinces’, As someone once said, a language is a dialect with an army and a navy.

  7. BTW, Dr. Bouldin, I long ago gave up on Nature. It seems to exist for a similar reason to a Credo in religion: it’s the go-to source whenever you want your orthodox beliefs backed up by supposedly unimpeachable authority.

    • I once had a ‘Correspondence Arising’ published in Nature, on the erroneous construction of climate science underlying climate negotiations – such as treating the problem as one of annual emissions, rather than accumulated stocks (with a 100 year residence time). Even though I was below the word limit, they cut the point that this changed the responsibility for the problem from the current emissions (eg USA) to Europe (Germany and Britain, which industrialised much earlier and share greater responsibility for elevated levels). A truth too inconvenient for them, I guess. I decided it was better to let them publish and then be able to tell the story than to withdraw consent, but it gives you an idea of their political sensitivities.

  8. You might want to add the obvious about those who are malnourished. If they get another mouth full on their plate (an extra 20% food) they will eat it.

  9. With climate change being blamed for almost everything these days, the one phenomenon that seems to have escaped the notice of scientists, environmentalists and the media alike is that, perhaps above all, climate change is making us stupid.

  10. Pingback: default position … “loss of trust” | pindanpost

  11. Here is another on for you Jim

    The rate of sea-level rise
    http://www.nature.com/nclimate/journal/v4/n5/full/nclimate2159.html

    Measurements show that the rate of sea level rise has slowed down in the last few years. So what we have to do is apply a “correction”. They “removed short-term variations in thermal expansion from the GMSL record”. After doing that they found that “there is no rate difference between the 1990s and the 2000s: the GMSL has almost linearly increased during the past 20 years”.

  12. My default position toward Nature (and PNAS for that matter), at least for environmental science papers (including climate science and ecology), has shifted from innocent until proven guilty, to roughly the opposite.

    You were young. It’s alright.

  13. (3) Their computations of how long it will take to reach ~ 560 to 580 ppm CO2 are off. We’re at about a 2 ppm/yr increase rate now (generously), there is no definite evidence for a strongly positive carbon cycle feedback, and so that rate equates to something like 80-90 years to 560-580 ppm, not their stated 40-70 years.

    According to the fossil fuel & cement emissions data stored at CDIAC preliminary information for 2012 emissions indicates the total was about 40% greater than in 2002, and about 90% greater than in 1982. There may not be a positive carbon cycle feedback over the next several decades but there’s no justification for a calculation which assumes human emissions won’t change.

    Tracking past fossil fuel + land use emissions with CO2 concentration growth, under the assumption of a net neutral carbon cycle feedback, indicates the current annual rate should be about 2.3ppm/yr. This is reasonably consistent overall with Mauna Loa and global marine CO2 measurements in recent years, including those for this year so far, despite persistent La Niña conditions.

    If the 40% decadal acceleration persists 560ppm would be reached at about 2055 with annual growth rate at that point being about 7.5ppm/yr. Being more conservative and assuming emissions growth acceleration will decline to a 20% decadal rate, 560ppm would be reached by about 2065.

    Whether or not these scenarios will transpire is entirely up in the air, but an estimate based on extrapolating a static growth rate into the future is less justifiable than the numbers given in the paper, and certainly provides no basis for criticism of such scenarios.

    • Good points Paul.

      I think there is some justification for a slowdown in the rate of pre-2008 atmospheric [CO2] acceleration however, given the observed decrease in the rate of increase since then and the increasing emphasis on alternative energy implementation. However, to the degree that this slowdown was due to a temporary economic recession, and/or La-Nina induced low C feedback rates, and not to any real change in energy policy/goals, then your point is well taken.

  14. More comments and replies not appearing when approved, no idea why.

    Comment from “Onlooker”:
    “That was my first reaction to the word too, but then I looked it up and apparently it’s one of the odd English English things; kind of like favourite.

    Glad to find your blog, Jim (thru Bishop Hill). The really poor science in the climate area is very dispiriting; and it parallels the poor nutritional science that has led us quite astray there over the last half century or so. But the ideologues continue their fight against the evidence regardless of the established facts.”

    My response:
    Human health and nutrition is one of the most important topics that scientists (and many others) can address, because it directly and very strongly affects human well-being in many ways. Obviously, there are many many factors that go into human nutrition, many many factors indeed. It burns me when I see a topic like this, which is mostly unrelated to atmospheric [CO2] issues, and for which we have very strong and definite evidence of other much more important factors, get hijacked just because CO2 is the hot, go-to topic right now. This is not acceptable; it diverts everyone from a true and balanced understanding of the problem, and hence, its solution. These authors make no attempt whatsoever to place these small Zn and Fe decreases over multiple decades in the context of larger issues. What’s the point of having 20 authors if you’re not going to engage in a wide-ranging discussion and place the findings in context?

  15. Jim, this is a poor effort and comes across as sour grapes or a spot of professional envy. (Perhaps you’re thinking about taking up Paul Matthews on his suggestion.)

    You wrote: ” It is not clear to me whether or not the lead author is a plant physiologist.” A thirty second google search would have given you your answer.

    http://chge.med.harvard.edu/about/people/samuel-s-myers

    Did you check the bibliography and listed WHO resources about risk factors relating to human nutrition?

    It’s an error to merely linearly extrapolate from current emissions to future emissions. Current emissions are causing an increase of just over 2 ppm globally on average (since 2000). The way things are going there is no reason not to think that emissions won’t follow the RCP8.5 pathway. Think about how much is already in the pipeline. The world is still building more GHG factories than replacing them with renewable energy.

    http://pdf.wri.org/navigating_numbers.pdf

    http://www.iea.org/publications/freepublications/publication/name,44381,en.html

    PS I was sorry to hear about your recent, um, malady. I hope you are soon feeling better and back to your normal self.

    • Oh OK, you want to get into a fight with your innuendo and attitude, do you?

      It’s entirely clear from your blog that, like many, you’re very one-sided on climate change issues and hence, very unlikely to criticize studies that claim negative effects of climate change or CO2 increase, or which involve bad methods. Just because A. Watts is very wrong on a lot of things doesn’t mean all the science–or scientists–are sound. Like a number of people, you see this whole thing as an “us vs them” battle of righteousness, whereas as a scientist, I’m simply concerned with the overall quality of the science. I’ve demonstrated this in many different ways with my writings here and elsewhere. Based on what I see you write, it’s not likely you’re ever going to understand that, and I ain’t the least bit interested in your simplistic, black/white view of the world, which is essentially what causes all the problems in the first place.

      As matters of fact, regarding your statements:
      1. Your opinion on the quality of the effort and how it “comes across” is irrelevant to me, and you are most certainly wrong in implying that envy has anything whatsoever to do with it. The fact that you would say such a thing pretty much illustrates your mindset.
      2. I did in fact spend quite a bit more than 30 seconds trying to find Myers’ information at the Harvard website, but without success. However, I did in fact discover, that just as I initially thought and stated, he is not in fact a plant physiologist, but rather a physician. In the process I’ve discovered some other interesting things about this topic and this paper, from actual plant physiologists who have worked on the topic, which if I get time, I’m going to get into.
      3. No, I have not yet had time to check their sources for claims about the number of people affected by Zn and Fe deficiencies and the number of person-years supposedly lost thereto, but my point was to question how sure they were of these claims, given that many exaggerated claims are made about the effects of carbon dioxide and climate change and they are throwing out very large numbers. Furthermore, I am not necessarily done with this topic, time permitting. But the main point is that the onus of demonstrating the veracity of a claim is on the claim maker, not the reader.
      4. Paul S has already raised your point on CO2, to which I’ve responded, and at any rate it’s a minor point in my overall argument. I should have known somebody would quibble on that, and could have raised any number of other points instead. Furthermore, your claim that a linear extrapolation is necessarily “an error”, is incorrect, since we’re talking about the future here. We won’t know until it actually happens.

      Given how you and your hostile attack dogs like Doug Bostrom responded to me at your website, when I gave an innocuous opinion on the usefulness of consensus arguments (and Cook’s paper) as defenses of the science, and given (1) that not a few days earlier I was very complimentary of what you were doing overall, and (2) your inability to be objective on science topics that you in fact don’t really understand the ins and outs of, there’s little point in interacting with you. I know exactly where your strategy originates in the blog-based climate discussions, believe me, a large part of which involves discrediting any scientist who is critical of any science related to climate change or CO2*, as well as the selective choice of articles to cite and the often biased interpretation of them. And I’m sorry that according to your website you apparently have some type of problem with men, but that’s not my problem, and if you think I’m going to spend my very limited time and energy arguing with you on quibbles and whatnot, either here or at your blog, you’re quite mistaken.

      *unfortunately, this problem originates from a few defensive and aggressive scientists, and certain bloggers take their lead from these people, one pernicious one in particular.

  16. I remember when I used to eagerly await the arrival of Nature at the library and, later, Sunday mornings perusing it on the web. It’s not worth much time anymore: too much proselytizing and shonky science. PNAS was always a bit weak, but is often embarrassing now. Oh well, I guess that is post-normal science.
    I saw a proposal for an IPCC-like UN assault on antibiotic-resistant bacteria this morning. I’m a bit surprised that MRSA hasn’t been blamed on CO2 yet. Perhaps I missed it or they’ve been saving antibiotic resistance for when the wheels fall off the global warming wagon. I once would have whole-heartedly supported such an endeavour, but the global warming fiasco has pretty much convinced me that no good would come of having an IPAR and probably a lot of bad.

Have at it

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s