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IPCC Special Report on Land

Thread for discussions of the new special report. [Boosting a comment from alan2102].

Climate Change and Land
An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems


Land degradation accelerates global climate change. Al Jazeera English
Published on Aug 8, 2019

New UN report highlights vicious cycle of climate change, land degradation. CNA
Published on Aug 8, 2019

New IPCC Report Warns of Vicious Cycle Between Soil Degradation and Climate Change. The Real News Network
Published on Aug 8, 2019

75 Responses to “IPCC Special Report on Land”

  1. 1
  2. 2
    alan2102 says:

    Keith Woollard: yeah, it is impressive to see it depicted in that way. I posted about this “greening” a few days ago on Forced Responses; the view expressed in the paper I cited was that it has been in good part due to deliberate land use changes. Nice to know that we humans can do good as well as ill; let’s hope it is the beginning of a big and enduring trend.

  3. 3
    Keith Woollard says:

    Yes, nice to imagine that it is a deliberate action, and they are welcome to their opinion, but it’s simply not true for the vast majority of the land surface. Mostly it is CO2. And certainly in Australia the huge areas of WA and NT have nothing to do with land use change

  4. 4
    Dan DaSilva says:

    Keith Woollard, the CO2 deprived plants are getting what they need. This will be met with derision because it does not comply with extreme alarmism. Science thrives in an atmosphere of the open mind just as plants thrive in an atmosphere of CO2, it is sad therefore that some would like to lower the value of both.

  5. 5
    Ray Ladbury says:

    Dan DaSilva,
    Yes, the poison ivy is thriving!

  6. 6
    David Appell says:

    Greening isn’t all good.

    Greening is a positive feedback on global warming, due to a change in albedo.

    Greening increases insect life, which affects crops humans depend on.

    Greening requires more water use by plants, when humans are already using about 1/2 the world’s supply of freshwater and many nations are on the brink of running out of water (see the NY Times the other day).

    Of course, if CO2 were so great for plants Venus, where the atmosphere is 96% CO2, would be teeming with plant life….

  7. 7
    Eli says:

    Keith Woollard – A picture may be worth a thousand words but you still need to understand what you’re looking at. Some of the greening is intentional. For example the impressive results of the “Great Green Wall” tree planting effort in China. But a lot of it is due to intensification of agriculture in vulnerable areas – e.g., areas reliant on irrigation from dwindling groundwater. Further, “… greening achieved through intensive agriculture does not have the same effect [on climate] … Instead, carbon absorbed by crops is quickly released back into the atmosphere.” https://www.futurity.org/green-leaf-area-earth-1985522-2/

    In addition, “… the gain in greenness seen around the world and dominated by India and China does not offset the damage from loss of natural vegetation in tropical regions, such as Brazil and Indonesia. The consequences for sustainability and biodiversity in those ecosystems remain.” https://www.nasa.gov/feature/ames/human-activity-in-china-and-india-dominates-the-greening-of-earth-nasa-study-shows

  8. 8

    Time to stop this tortured trope that somehow increased CO2 levels will feed the future. There are so many studies about atmospheric pollution and agriculture. One set is about how increased tropospheric ozone levels harm plants and all living tissue. Federal studies since 1961 have dug into this. Any increase in growth rate is more than offset by the caustic effects of ozone – from tomatoes to tobacco plants, ozone harms yields.

    https://e360.yale.edu/features/ground_level_ozone_harming_plants_humans

    https://scied.ucar.edu/blog/how-does-ozone-damage-plants

  9. 9
    Dennis N Horne says:

    #4 Dan DaSilva. Many plants thrive in warmer climes too but keep heating them and you’ve cooked dinner.

    Have you ever stopped to wonder why you imagine you know more about climate change than the global community of scientists? I assume you don’t feel the same about relativity, quantum mechanics, plate tectonics, evolution…

    Actually, please tell me you do…

  10. 10
    alan2102 says:

    Dan DaSilva 9 Aug 2019:
    “the CO2 deprived plants are getting what they need. This will be met with derision because it does not comply with extreme alarmism.”

    Plants are not “CO2 deprived”. They grow somewhat faster, other things equal, with more CO2. That increased growth comes at a price (relative depletion of other nutrients), if other things ARE equal. The nature and implications of that price are being teased-out as we speak; more publications on it almost every month. Nevertheless, this greening — more primary production — is generally a good thing. It is just unfortunate that it has fed into denialist narratives and been presented as though indicating that everything is hunky-dory.

    I’ve experienced that “derision because it does not comport with extreme alarmism”, but not from scientists. The scientists get it. Greening is described frankly on page 6 of this new report, paragraph A2.3. There is no controversy about it. It is a fact, and to a limited extent an encouraging one. It is one factor in a complex, multifaceted interactive mess that is still incompletely understood. The denialists pay no attention to that context of complexity, however, yanking the naked fact of greening out of that context and presenting it as though it were THE REALLY BIG THING that Proves The Liberal Tree-Hugger Climate People All Wrong. Idiots.

    But you’re correct that certain alarmist types, doomers, Luddites and committed Malthusians are offended by the idea that anything could possibly go right, and that maybe the hated “industrial civilization” IS capable of effective self-corrective action, after all. Hence the snarky remark at the end of my recent post on the subject:
    http://www.realclimate.org/index.php/archives/2019/07/forced-responses-aug-2019/#comment-742155

    Regarding “if other things ARE equal”: They don’t have to be, and we can ensure that they aren’t. Can you guess how?

  11. 11
    alan2102 says:

    #3 Keith Woollard 9 Aug 2019:
    “Yes, nice to imagine that it is a deliberate action, and they are welcome to their opinion, but it’s simply not true for the vast majority of the land surface. Mostly it is CO2.”

    According to the paper I cited, it is at least one third due to the “direct factor” (deliberate human intervention, not CO2):
    http://www.realclimate.org/index.php/archives/2019/07/forced-responses-aug-2019/#comment-742155
    quote: “Our results indicate that the direct factor is a key driver of the “Greening Earth”, accounting for over a third, and likely more, of the observed net increase in green leaf area.”

    Not mentioned is the possibility that with committed, organized and persistent effort, we could (and should) raise that fraction to two thirds, perhaps, or even more. We need a much better, more self-conscious Greening Earth initiative, to do it RIGHT from this moment forward, instead of continuing the half-assed and problematic way we’ve done it so far. It is good as far as it goes, but it does not go nearly far enough.

  12. 12
    William B Jackson says:

    No 4 Studies have shown that trees grown under higher CO2 conditions are weaker and more prone to failure under high wind condition, and further that the leaves,seeds and fruits of all kinds of plants are of lower nutritional value. So much for that!

  13. 13
    nigelj says:

    Regarding the comment @1 related to the so called “greening of the planet” due to elevated CO2 levels: Clearly there is an effect that is well well documented, but leafier trees are of no use unless this has a powerful effect on drawing down atmospheric concentrations of CO2, and clearly the MLO data does not show such an effect, as it continues to go up!

    Regarding the impact of elevated CO2 levels on crops, the news is not all that good:

    https://www.nasa.gov/feature/goddard/2016/nasa-study-rising-carbon-dioxide-levels-will-help-and-hurt-crops

    “Studies have shown that higher concentrations of atmospheric carbon dioxide affect crops in two important ways: they boost crop yields by increasing the rate of photosynthesis, which spurs growth, and they reduce the amount of water crops lose through transpiration. Plants transpire through their leaves, which contain tiny pores called stomata that open and collect carbon dioxide molecules for photosynthesis. During that process they release water vapor. As carbon dioxide concentrations increase, the pores don’t open as wide, resulting in lower levels of transpiration by plants and thus increased water-use efficiency….”

    “Results show that yields for all four crops grown at levels of carbon dioxide remaining at 2000 levels would experience severe declines in yield due to higher temperatures and drier conditions. But when grown at doubled carbon dioxide levels, all four crops fare better due to increased photosynthesis and crop water productivity, partially offsetting the impacts from those adverse climate changes. For wheat and soybean crops, in terms of yield the median negative impacts are fully compensated, and rice crops recoup up to 90 percent and maize up to 60 percent of their losses.”

    So to get some rather limited advantage from higher CO2 levels requires a doubling of CO2 levels, so potentially dangerous levels of climate change based on IPCC assessments. This looks like a deal with the devil to me, that isn’t compelling, especially as humanity has many other options to increase agricultural yields such as improved crop varieties, genetic engineering, or just wasting less food and getting population numbers down.

    Another view:

    https://www.scientificamerican.com/article/ask-the-experts-does-rising-co2-benefit-plants1/

    “Climate change’s negative effects on plants will likely outweigh any gains from elevated atmospheric carbon dioxide levels”.

  14. 14
    Dan DaSilva says:

    Dennis N Horne quote “Have you ever stopped to wonder why you imagine you know more about climate change than the global community of scientists?”

    That has never crossed my mind because I do not know more about climate change than the global community of scientists. I may not even know more than you.

    Has a person ever disagreed with a global community of scientists and been correct? Who cares, if you want to take everything from authority just stop thinking and go with the consensus, you will usually be right. You will also be functionally brain dead.

  15. 15
    Matthew R Marler says:

    5, Ray Ladbury: Yes, the poison ivy is thriving!

    Is it?

    Could a change toward a greener environment occur that did not promote poison ivy along with everything else? Does increased CO2 (or increased temp or increased rainfall) give poison ivy a competitive advantage.

  16. 16
    Sou says:

    There are some ominous messages in this latest report, including that land is finite (duh), arable land is finite (duh again), food security is at risk, and deforestation must be addressed urgently.

    I’ll be reading it over the next few days (maybe weeks). There is a lot to digest and, at first look, some parts I’d regard as overly optimistic, and some parts gloss over important issues.

    One small example is this sentence (from 5.5.2.1), which is part of a discussion about mitigating climate change by changing diets. It dismisses the problems of abandoned pastoral land thus:

    “When the transition to a low-meat diet reduces the agricultural area required, land is abandoned and the re-growing vegetation can take up carbon until a new equilibrium is reached. This is known as the land-sparing effect.”

    If only. It is likely that “re-growing vegetation” will be weeds or saltpans. Land doesn’t return to its pre-agricultural state by magic. It takes deliberate action to restore it.

    I’d warn against assuming that changing diet or reducing food waste will directly lead to reduced emissions. It is more likely that this will help food security and be a beneficial adaptation rather than mitigation. That is, maybe if food waste is successfully reduced and diets change, there’ll be enough food produced to feed everyone without clearing too much more land for farming, as population increases.

    Overall, for people who were not aware of the impending food supply problems, or not aware of the damage caused by deforestation, this report is a good start. The detail has some problems IMO. All in all, it’s a cause for concern and a call to action rather than a message of hope.

    I hope to blog about this report sooner rather than later. Maybe I will find some points to celebrate, though I fear there won’t be too many.

  17. 17
    Dennis N Horne says:

    #14. Dan DaSilva: Has a person ever disagreed with a global community of scientists and been correct? Who cares, if you want to take everything from authority just stop thinking and go with the consensus, you will usually be right. You will also be functionally brain dead.

    When you get out of bed in the morning do you check to see if you are walking on the ceiling?

    Accepting a solid consensus based on the evaluation of masses of evidence by experts is not submitting to authority without thinking. It’s what rational people, including scientists, do.

    Consensus is not part of doing science, but it is a natural consequence of doing it right. You can’t wave that away with banal comments.

    You do not exhibit a healthy scepticism and a search for understanding, merely invincible ignorance and tiresome incredulity.

    Be not concerned about seeming “functionally brain dead”.

  18. 18
  19. 19
    CCHolley says:

    re. DaSilva @14

    Has a person ever disagreed with a global community of scientists and been correct? Who cares, if you want to take everything from authority just stop thinking and go with the consensus, you will usually be right. You will also be functionally brain dead.

    If someone disagrees with a global community of scientists and turns out to be correct it is because they actually have some knowledge of what the science actually says with additional knowledge to base their disagreement. Not so for the likes of Dan DaSilva, who even admits to an inferior level of comprehension. There is a big difference in taking everything from authority versus actually attempting to understand what the science actually tells us and formulating a position based on analysis of information and the use of critical thinking skills. DaSilva apparently does not recognize the distinction nor does he recognize a sound argument when it is put right in front of his nose. The irony clearly lies in DaSilva proclaiming who is functionally brain dead.

  20. 20
    barry says:

    A fraction of a fraction of a percent change of CO2 in the atmosphere couldn’t possibly have an effect on the biosphere, but – lo! – it is responsible for greening the planet. At the same time, such an insignificant amount could not possibly affect global temperature. Because it’s insignificant.

    Is there a coherent thesis for rejecting AGW, or is it all simply denial?

  21. 21
    Al Bundy says:

    Dan DaSilva: Dennis N Horne quote “Have you ever stopped to wonder why you imagine you know more about climate change than the global community of scientists?”

    That has never crossed my mind because I do not know more about climate change than the global community of scientists. I may not even know more than you.

    Has a person ever disagreed with a global community of scientists and been correct? Who cares, if you want to take everything from authority just stop thinking and go with the consensus, you will usually be right. You will also be functionally brain dead.

    AB: Has a person ever bought a lottery ticket and won? I’ve got a lottery ticket I’ll sell you for a mere $1000. “It could happen” or even “It must happen somewhere” says essentially nothing about the odds that the ONE ticket in my hand being a winner.

    And read your comment. You’re saying that you are most likely flat-out-wrong yet you don’t approach the science from a “what can I learn and contribute” angle but “how can I become the heaviest anchor?” The way to tell the difference is your second or third comment on a subject. Sure, start with “But CO2 is a raw material for plant growth”. Then folks-who-aren’t-as-bone-ignorant-as-you tell you the various reasons and studies (lower strength, lower protein, lower vitamins, lower phytonutrients, more drought, more flood damage, etc etc etc..) Why, you surely look at the USA’s breadbasket and laugh at the farmers who are whining about the impossible: floods and drought in a single growing season. Obviously, as every anchor knows, the two are mutually exclusive so the only conclusion is that USAian farmers are horrible at farming. Why, they’re even benefiting from increased CO2 and nothing is anywhere near as important to my argument than that (“importance to my argument” is light-years more critical than “importance to the physical system”).

    …and at that very moment you have a choice. Do you want to remain an ignorant anchor or to learn and contribute? So far your choice has been consistently anchoresque.

    Kind of a DK corollary: Even when a person knows he is ignorant and non-expert, if he’s stupid enough he’ll hold onto his ill-formed conclusions for dear life.

    Oh, and by the way, anchors are functionally brain-dead so you’ve stumbled into being exactly what you dissed above.
    ________________

    Matthew,
    “These elevated carbon dioxide levels are creating bigger, stronger poison ivy plants that produce more urushiol, the oil that causes the allergic reaction and miserable poison ivy rash. The urushiol isn’t just more plentiful; it might also be more potent.”
    “In the last 50 years, Ziska says, the growth rate of the poison ivy plant has doubled.”
    https://www.webmd.com/skin-problems-and-treatments/features/climate-change-brings-super-poison-ivy#1

  22. 22
    Dan DaSilva says:

    Al Bundy
    The poison ivy gets stronger while helpful plants get weaker. That is the ultimate proof of just how selectively evil increased a level of CO2 really is (sarcasm). This is the same thinking that maintains that every possible outcome of increased global warming is bad. This thinking is called Idelogicall Possession. No real thinking is required, just run every thought through your ideological filter. This thinking can never be penetrated so I am writing this for those who are self-aware enough to judge on merits or lack thereof.

  23. 23
    Al Bundy says:

    CCHolley: If someone disagrees with a global community of scientists and turns out to be correct it is because they actually have some knowledge of what the science actually says with additional knowledge to base their disagreement.

    AB: Generally, no. This is an actuarial problem somewhat equivalent to the “broken clocks are right twice a day” joke. You gather 7 billion folks onto a planet and most assuredly thousands and thousands of them will randomly be correct in their unwavering belief that scientific consensus is wrong and they’s right about one factoid or another. But then, you’d have better odds betting on 00 in roulette than on betting that one individual denier is correct and consensus is wrong about even one significant and relevant factoid.

    “Dan’s” lesson is that unless you are ready, willing, and able to do the work (and already have) then you MUST use “argument of authorities” (“I’m ignorant but these folks seem trustworthy”). And if you are deciding who’s trustworthy do you think it’s the barely bright who scarf up every dollar they can or the brilliant folks who voluntarily work in cinder block offices for middle class wages?

    Seriously, Dan DS, no BS. WHO would YOU trust with your cash if you KNEW that one and only one of the above would rip you off? That’s a friggin’ real question. Do you have the balls and the integrity to answer honestly?

    _______________
    barry: A fraction of a fraction of a percent change of CO2 in the atmosphere couldn’t possibly have an effect on the biosphere, but – lo! – it is responsible for greening the planet. At the same time, such an insignificant amount could not possibly affect global temperature. Because it’s insignificant.

    Is there a coherent thesis for rejecting AGW, or is it all simply denial?

    AB: you win the Comment of the Day Award! (Yeah, I’m not a moderator/owner of this site and there is no prize, but still…)

  24. 24
    nigelj says:

    Al Bundy@23, “you gather 7 billion folks onto a planet and most assuredly thousands and thousands of them will randomly be correct in their unwavering belief that scientific consensus is wrong and they’s right about one factoid or another.” Yes but the same people will mostly be incorrect about other consensus issues. Only people with expertise would have a good track record of being correct in identifying bad science. Agree about the other points.

  25. 25
    Lynn says:

    Just downloading the report. I wrote an article years ago “Food Rights, Food Frugality, and Climate Change” for Foodways, came out in 2012 (so it’s out-of-date now): https://www.tandfonline.com/doi/abs/10.1080/07409710.2012.652028

    ABSTRACT: Climate change-related food issues are key problems affecting the world today and into the future. This paper investigates how climate change is harming and is expected to harm food sources on land and in the sea, and how food production itself, especially industrialized agriculture and meat production, contributes to climate change. This article uses human rights discourse to frame the unequal contributions to and harms from climate change among developed and developing nations, and how these affect and are affected by involuntary and voluntary food frugality and dietary choices.

  26. 26
    CCHolley says:

    AB @23

    I guess I didn’t make myself clear. My point was that science is generally advanced by those knowledgable in the given field who gain new information through observation and/or experimentation, not some random denialist. The odds of Dan DaSilva ever being right is about as far as you can possibly get from happening because he is not interested in actually doing any work to gain knowledge beyond his politically motivated denialism. To me his inaccurate accusation of people solely relying on an appeal to authority to make their case on this site is just an excuse for his denialism. You stated it better.

  27. 27

    Ah, CO2 and poison ivy! As Hank Roberts used to say–and maybe still does, though I haven’t seen him say it lately–“‘Oogle is your friend.”:

    It is not known how poison ivy might respond to increasing concentrations of atmospheric carbon dioxide (CO2), but previous work done in controlled growth chambers shows that other vines exhibit large growth enhancement from elevated CO2. Rising CO2 is potentially responsible for the increased vine abundance that is inhibiting forest regeneration and increasing tree mortality around the world. In this 6-year study at the Duke University Free-Air CO2 Enrichment experiment, we show that elevated atmospheric CO2 in an intact forest ecosystem increases photosynthesis, water use efficiency, growth, and population biomass of poison ivy. The CO2 growth stimulation exceeds that of most other woody species. Furthermore, high-CO2 plants produce a more allergenic form of urushiol. Our results indicate that Toxicodendron taxa will become more abundant and more “toxic” in the future, potentially affecting global forest dynamics and human health.

    https://www.pnas.org/content/103/24/9086/

    Related team, a year later:

    Overall, these data confirm earlier, field-based reports on the CO2 sensitivity of poison ivy but emphasize its ability to respond to even small (∼ 100 µmol mol−1) changes in CO2 above the mid-20th century carbon dioxide baseline and suggest that its rate of spread, its ability to recover from herbivory, and its production of urushiol, may be enhanced in a future, higher CO2 environment.

    https://www.cambridge.org/core/journals/weed-science/article/rising-atmospheric-carbon-dioxide-and-potential-impacts-on-the-growth-and-toxicity-of-poison-ivy-toxicodendron-radicans/4DED41371F319726B3F54D579817DD20

    So, yeah, there’s some fairly good reason to think that poison ivy (along with other climbing vines) will/are benefitting preferentially from CO2 fertilization. It’s purely anecdotal, of course, but that sure seemed to me to be the case on my old place in Georgia, and I think also here in South Carolina.

  28. 28

    Is there a coherent thesis for rejecting AGW, or is it all simply denial?

    No.

    The narrative is that “It isn’t happening, but no-one denies that it’s happening, and besides it’s happening at the same rate on Mars, Jupiter, and Pluto (which we can measure precisely because there’s no urban heat effect there), and if it were happening it would be the sun, but it couldn’t be because the Earth is so big. And if it were happening, it wouldn’t be a bad thing, anyway, because it would just be an Ice Age recovery.”

  29. 29
    Matthew R Marler says:

    27, Kevin McKinney: may be enhanced in a future, higher CO2 environment.

    may be? Has it been observed to date?

  30. 30
    Matthew R Marler says:

    21 Al Bundy, thanks for the link.

  31. 31
    alan2102 says:

    #7 Eli 9 Aug 2019
    “a lot of it is due to intensification of agriculture in vulnerable areas e.g., areas reliant on irrigation from dwindling groundwater.”

    Good point, but is it really “a lot of it” or just a modest fraction of it? We don’t know. We do know that a large portion of it was forest, not cultivated area. As for the latter, what fraction is/was irrigated is not known.

    Regardless, your point about water is well-taken. Water is a serious global problem. However, I think it is SOMEWHAT less of a problem than you might imagine, both in China and elsewhere. I will post a few notes on the subject later, separately.

    “Further, ‘greening achieved through intensive agriculture does not have the same effect [on climate] Instead, carbon absorbed by crops is quickly released back into the atmosphere.'”

    Also a good point, with a couple exceptions.

    1. Carbon sequestration is not the only important thing. Plants provide numerous vital ecosystem services.

    2. Carbon absorbed by crops is less important than carbon sequestered in soil. There is consensus that soil carbon is a large potential sink. The greening resulting from agricultural intensification is associated with mineral fertilizer application. This fertilizer use increases soil carbon, in China and elsewhere:

    http://www.ncbi.nlm.nih.gov/pubmed/27251021
    Sci Rep. 2016 Jun 2;6:27199. doi: 10.1038/srep27199.
    Changes in soil organic carbon in croplands subjected to fertilizer management: a global meta-analysis.

    http://www.ncbi.nlm.nih.gov/pubmed/30479909
    PeerJ. 2018 Nov 16;6:e5983. doi: 10.7717/peerj.5983
    Recommended nitrogen fertilization enhances soil carbon sequestration in China’s monsoonal temperate zone.

    http://www.ncbi.nlm.nih.gov/pubmed/29035007
    Glob Chang Biol. 2018 Mar;24(3):987-1000. doi: 10.1111/gcb.13898
    Large soil organic carbon increase due to improved agronomic management in the North China Plain from 1980s to 2010s.

    …. in other words, the greening that we see is a sort of “tip of the iceberg”, likely reflecting changes in soil carbon — a very good thing.

    All that is apart from the fact that in China, at least, most of the greening resulted from afforestation (much longer carbon sequestration). China’s example suggests that, with proper planning and effort, further greening could be more in the forest than agricultural sector, thereby promoting longer-term carbon sequestration.

    “In addition, ‘the gain in greenness seen around the world and dominated by India and China does not offset the damage from loss of natural vegetation in tropical regions, such as Brazil and Indonesia.'”

    No, of course it doesn’t, and only denialist idiots would suggest otherwise. But let’s not turn into equal-and-opposite idiots by dismissing a manifestly good thing. Would you really rather be living in a world in which those tropical regions are damaged as they are, but NOT accompanied by the greening in question? No, of course you wouldn’t.

    To say that something good happened does not mean that that (good) thing compensates for all the bad things that are happening; it just means what it says: something good happened.

    Any good thing that you can possibly imagine will not, in isolation, compensate for all the bad things. But we’ll take them, because a good thing is a good thing, even if it does not solve all of the world’s problems. And if we make enough good things happen — who knows? — maybe we can recover from the awful mess we’ve created.

  32. 32
    alan2102 says:

    #8 Richard Pauli 9 Aug 2019
    “Time to stop this tortured trope that somehow increased CO2 levels will feed the future.”

    Increased CO2 will have a positive quantitative effect on agricultural productivity, probably not enough to compensate for the negative effects of other aspects of climate change, and also with negative side-effects, notably nutritional depletion. Only denialist idiots suggest that increased CO2 is a wonderful blessing, (I agree that it is a “tortured trope” with them), but let’s not turn into equal-and-opposite idiots by denying the facts of CO2 fertilization. The IPCC doesn’t; the scientists don’t; why should we?

  33. 33
    alan2102 says:

    #12 William B Jackson 9 Aug 2019
    “trees grown under higher CO2 conditions are weaker and more prone to failure under high wind condition”

    Soils are depleted of the elements necessary for synthesis of structural carbohydrates that impart strength and elasticity, notably silicon and boron. Silicon in particular has been massively depleted over many decades of intensive grain cultivation without compensatory repletion:

    DOI 10.1007/s40011-013-0270-y — “the silicon removed from world arable soils is estimated to the tune of 210-224 million tons annually (FAO estimate).”

    We could resolutely sit on our hands and fail to replete soils with these elements; that failure would result in numerous problems including, but far from limited to, the weakness you mention. OR we could do otherwise. Our choice.

    Higher CO2 conditions are baked into the cake for many decades. It is a *fait accompli*, whereas soil nutrient depletion is not.

    “the leaves, seeds and fruits of all kinds of plants are of lower nutritional value.”

    Indeed. Same point: We could resolutely sit on our hands and fail to nutrify soils with the elements required to compensate for the dilutional effect of higher CO2; that failure would result in numerous problems including, but far from limited to, the nutritional problems you mention. OR we could do otherwise. Our choice.

    Further: said soil nutrification needs to be done ANYWAY, climate change or no. A couple billion humans are already malnourished with these elements and desperately need a comprehensive, widely-implemented soil nutrification program to correct or mitigate. This is an urgent global public health priority, being made still more urgent by the onrushing climate crisis.

  34. 34

    #29, MRM–

    Read the study, if you care; I provided the links. I merely quoted what they said in the abstract.

  35. 35
    Matthew R Marler says:

    20, Barry: Is there a coherent thesis for rejecting AGW, or is it all simply denial?

    AGW subsumes a lot of propositions about processes and their rates.

    So it makes more sense to ask the question about particular propositions, their evidentiary support, and contradictions and critiques.

    Increasing CO2 in the atmosphere will cause warming of the troposphere. Some people dispute that — I am not one of them, and their writings strike me as, shall I say, “unhinged”.

    Warming the troposphere will cause warming of the surface. Again, some people try to dispute that on spurious 2nd law of thermodynamics grounds, but I agree with the proposition.

    The climate sensitivity to a doubling of atmospheric CO2 is in the range 1.5K-4.5K (90% CI). Higher estimates tend to be older (at least in my reading) and based on uniform priors that put, for example, 10% probability in the intervals 3-4 and 9-10, which I think is unreasonable. Later estimates (again, in my reading) eschew the Bayesian methods and get estimates toward the lower end. But the range of uncertainty has hardly changed in 20 years, as no estimation procedure produces a precise result. I presented a calculation a couple years ago supporting a surface climate sensitivity less than 1K; I am a priori unlikely to be correct, and I would like to see more work along the path I outlined.

    and so on, up to things like AOC’s Green New Deal.

  36. 36
    Dan DaSilva says:

    26 CCHolley says
    “The odds of Dan DaSilva ever being right is about as far as you can possibly get from happening”
    Being right about what? I agree that there is AGW, is that right? This whole discussion has very little to do with facts. Which why it is so appropriate that Gavin has posted “Just the Facts?”
    To stir up this site’s comment section simply state the most obvious fact to indicate some small deviation from alarmism and off we go. You guys realize that this is not SLATE.COM do you not? Maybe we need a new site “realclimatefeelings.org”.

  37. 37
    Al Bundy says:

    CCHolley: I guess I didn’t make myself clear

    AB: Naw, I was too focused on Dan. My other thought (unstated) was that since the experts’ ad nauseum mantra is, “It’s worse than we thought”, several non-experts here can claim that they’ve “beat the experts” (Killian comes to mind). Note that such “winning” hasn’t and won’t advance diddly (but it strokes the ego). None of this detracts from your point.
    _____

    Dan DaSilva: Being right about what?

    AB: The full comparison was, “being right where scientific consensus is wrong”. Methinks you just reinforced CC’s point.

  38. 38
    William B Jackson says:

    No 33 What does soil depletion have to do with an excess of CO2? I am all for fixing soil levels of silicon et al but….

  39. 39
    Al Bundy says:

    Dan DaSilva: The poison ivy gets stronger while helpful plants get weaker. That is the ultimate proof of just how selectively evil increased a level of CO2 really is (sarcasm). This is the same thinking that maintains that every possible outcome of increased global warming is bad.

    AB: Basically, you’re accusing facts of not aligning with your

    DDS: Idelogicall Possession. No real thinking is required, just run every thought through your ideological filter

    AB: which is why I never comment with the expectation that folks like you will ever recognize that your complaints exactly describe yourselves. I love to entertain while educating (not you but using you). Thanks for being your “idelogicall” self. A visualization: weeds are generally hardier than crops because weeds are opportunistic and crops have been warped into a narrow niche where they need help to survive, and crops’ value to humanity suffers when said niche is changed because the crops need to become weedier to survive outside of their comfort zone. What’s amazing is that even when the facts are pointed out in an irrefutable fashion

    DDS: This thinking can never be penetrated

    AB: Oh, by the way, based on the smoke coming out of your ears methinks your filter needs changing. Understandable. It must take a lot of energy to warp pure science and fact into an irrelevant and moronic political diatribe.

    Please entertain us with the alternative facts that Drumpf reality. (Start with your answer to my trust question above) And a tip: writing with all the skills of a fifth grader who’s flunking English isn’t a grand way to impress anyone with more than the Donald’s IQ.
    ____________

    MRM: The climate sensitivity to a doubling of atmospheric CO2 is in the range 1.5K-4.5K (90% CI). Higher estimates tend to be older (at least in my reading)

    AB: Actually, the opposite. The newest estimates are trending higher, with at least eight models estimating 5+C.
    https://science.sciencemag.org/content/364/6437/222

  40. 40
    CCHolley says:

    DaSilva @36

    Being right about what?

    Remember you wrote: “Has a person ever disagreed with a global community of scientists and been correct?”

    Meaning as Al Bundy said: “being right where the scientific consensus is wrong”

    Speaking of facts, the fact is, you fail to learn what the facts actually are. Therefore, the likelihood of the likes of you disagreeing and being correct is less than one in a billion.

  41. 41
    alan2102 says:

    #48 William B Jackson 14 Aug 2019
    “No 33 What does soil depletion have to do with an excess of CO2? I am all for fixing soil levels of silicon et al but….”

    CO2 is a plant nutrient, but it is only one of dozens. It stimulates growth of inferior quality, just as you asserted: “trees grown under higher CO2 conditions are weaker and more prone to failure under high wind condition”. And why are they of inferior quality? Because of oversupply of the naked nutrient CO2 in the absence of an adequacy of the panoply of nutrients needed for healthy, strong plants (and soils, and animals, and people). It is an imbalance problem. We could invoke Liebig’s law of the minimum, and in this case that which is at “minimum” is everything except for one thing — CO2!

    The problem you cite — “weaker and more prone to failure” — is not caused by some mysterious, heretofore unknown direct toxic effect of CO2. It is caused by CO2 acting as a growth stimulant without the necessary complement of nutrients that impart strength. Like if you came up with some strange hormonal/chemical treatment for short children that caused rapid longitudinal bone growth, but forgot to accompany that with the nutrients required for strong bones, resulting in long but porous and weak bones — “weaker and more prone to failure”.

    The problem of pre-existing soil depletion is different but related; it exacerbates the problem just described above. In other words, we would be in trouble with higher CO2 levels even if we were dealing with virgin, nutrient-rich soils not having been depleted by extractive agriculture for a century. However, we ARE dealing with such depleted soils, hence the problem is much worse than it would have been. The non-CO2 nutrients have been depleted (most of them, at least*) while CO2 has been increased. Double-whammy.

    Understand? Please let me know if you don’t. I want to do my best and I would like the feedback. Thanks.

    ……..

    * A few nutrients are routinely supplemented, notably nitrogen, and some phosphorus and potassium. Nitrogen acts, like CO2, as a growth stimulant, and there is no denying the greatly increased yields that result. But again, it is increased yield at a price, and the price includes further depletion of the non-supplemented nutrients, numbering in dozens, notably Zn, Fe, Cu, I, B, Si, Mg, Ca, S.

  42. 42
    alan2102 says:

    Extinction Rebellion’s Roger Hallam, in an interview by Chris Hedges (on RT about a week ago): “We’re looking at the collapse of the world’s agricultural systems”. Many others have made similar remarks, including people on this (RC) forum in past years.

    What is the basis for such an outlook? Is there any evidence for it? Not that I’ve seen, and I’ve now read quite a bit. True that absence of evidence is not evidence of absence, but still, a prediction of imminent doom (outside a religious context; “armageddon”) ought to be accompanied by at least some empirical support. I’m not seeing it.

    Scientists in the relevant areas (agriculture, agronomy vis a vis climate) — in my experience having read hundreds of papers and perhaps a couple thousand abstracts — NEVER speak of forthcoming collapse, and I don’t just mean that they do not use the word “collapse”, but rather that their projections and speculations never convey anything remotely like collapse. They speak in cautious terms of incremental effects on, say, wheat yields; they project that yields might decrease (or increase) to some degree, usually a single-digit or low double-digit percentage, over a period of years or decades, in a given locale, given different variables or combinations of variables including climate and abiotic stresses. But again, nothing remotely corresponding to “collapse”.

    So, where does this idea about “collapse of the world’s agricultural systems” come from? It sounds to me like pure apocalypticism. Fear-mongering.

    If anyone has a fact-based, non-religious argument for “collapse of the world’s agricultural systems” — an argument linked (even tenuously!) to the scientific literature — then please present it.

    ……………

    Nota bene: Please do not infer from the above that I am generally optimistic or that I don’t think there will be famines and starvation. I am not optimistic and I think there will likely be famines and starvation (just as there are right now, only worse). The question is of CAUSE. I do not see a basis for the belief that those terrible things will be caused by a collapse of the world’s agricultural systems. Convince me that I am wrong.

  43. 43
    Al Bundy says:

    Alan2102,

    Agreed, and I note that plants adjust the number of stomata (holes where CO2 can get in) in their leaves to accomodate different CO2 levels over geological time. IF CO2 were “pure good” THEN stomata would maximize and stay that way regardless of CO2 levels. But we see that when CO2 levels go up they protect themselves from excess CO2 by evolving to have fewer stomata. (Cooling et al are also involved in the “equation”)

  44. 44

    ab, #43–

    (Cooling et al are also involved in the “equation”)

    Good ol’ H2O being a notable one of the alii…

  45. 45
    mike says:

    lmgtfy, Alan 2012:

    http://www.lloyds.com/~/media/files/news%20and%20insight/risk%20insight/2015/food%20system%20shock/food%20system%20shock_june%202015.pdf

    https://www.birdlife.org/europe-and-central-asia/news/intensive-farming-shepherding-collapse-living-world

    https://socialnewsdaily.com/71947/society-collapse-2040/

    https://www.progress.org/articles/us-agriculture-will-collapse

    I don’t know how likely the collapse is because I think the studies and predictions are generally based on models run on a BAU trajectory. But, as to the question, does anyone know of a fact-based, non-religious argument for “collapse of the world’s agricultural systems”

    there it is. I don’t think religion is a factor in these arguments.

    Should be ok, 7 fat years, then 7 lean years. It all works out.

    Warm regards

    Mike

  46. 46

    a 42: “We’re looking at the collapse of the world’s agricultural systems”. Many others have made similar remarks, including people on this (RC) forum in past years.

    What is the basis for such an outlook? Is there any evidence for it? Not that I’ve seen, and I’ve now read quite a bit. True that absence of evidence is not evidence of absence, but still, a prediction of imminent doom (outside a religious context; “armageddon”) ought to be accompanied by at least some empirical support. I’m not seeing it.

    BPL: http://www.ajournal.co.uk/pdfs/BSvolume13(1)/BSVol.13%20(1)%20Article%202.pdf

  47. 47

    #45, mike–

    Links worth a look. Having looked, though, only #3 actually projects a system-wide agricultural collapse. (#1 says the system is vulnerable to a “shock”, which would clearly be Very Bad Thing, but not as permanent. #2 says EU ag policy is wrecking nature–again, a Bad Thing. #4 says US ag will collapse because of unsustainable water use–specifically, the depletion of aquifers by over-pumping.)

    The only one really reporting in any depth is #1, and even there one sees a jarring superficiality, largely because it’s scoped toward relevance to the insurance industry–you actually get “Millions of people could die, but at least there will be opportunities for insurers!”

    #3 comes from the Global Sustainability Institute at Anglia Ruskin University–their page on “risk and resilience research” is here:

    https://aru.ac.uk/global-sustainability-institute-gsi/research/global-risk-and-resilience

    “mintpressnews” had a 2015 report discussing both the Lloyd’s work and the GSI report, by Dr. Nafeez Ahmed:

    https://www.mintpressnews.com/society-to-collapse-by-2040-due-to-catastrophic-food-shortages-environmental-disaster/206797/

    Apparently both reports stem back to the GSI, and have significant British governmental support and involvement, chiefly through the Foreign & Commonwealth Office (FCO). I’m still trying to find a link for the actual report on system collapse itself–difficult, as no-one, including Ahmed, seems to want to give the actual name or publication date of the damn thing.

    Possibly, there isn’t yet an actual publication. Ahmed says he attended “an invite-only GRO steering committee meeting of scientists, technologists, financiers, economists, and academics, where GSI’s Director, Dr. Aled Jones, delivered a detailed presentation on the modelling work done so far…” So maybe publication is pending–or not. At any rate, the research focus seems to be more about resource constraints in general, not about agricultural collapse, which (I remind myself) is what I’m supposed to be looking at here.

    The Global Resource Observatory, at least, is here:

    https://aru.ac.uk/global-sustainability-institute-gsi/research/global-risk-and-resilience/global-resource-observatory

    This is an overview paper which seeks to clarify what we might mean by “collapse” anyway, and what some folks have written about it so far:

    https://mahb.stanford.edu/wp-content/uploads/2019/03/cumming2017_UnifyingResearchonSocial-EcologicalResilience.pdf

    This is a link to the recent CSIRO update of the famous “Club of Rome” research, which essentially says that CoR was probably right, and we’re well down the road to hell, with only a few of us checking off the landmarks as we pass:

    https://espas.secure.europarl.europa.eu/orbis/sites/default/files/generated/document/en/MSSI-ResearchPaper-4_Turner_2014.pdf

  48. 48
    Matthew R Marler says:

    39, Al Bundy, AB: Actually, the opposite. The newest estimates are trending higher, with at least eight models estimating 5+C.
    https://science.sciencemag.org/content/364/6437/222

    Thanks for the link.

    Doesn’t that predict a warming of 3C for the 20th century, for CO2 alone?

  49. 49

    #48, MRM–

    Doesn’t that predict a warming of 3C for the 20th century, for CO2 alone?

    No, because ECS (‘Equilibrium Climate Sensitivity’) is defined on an instantaneous doubling of CO2. We still haven’t reached that doubling, as 20 years into the 21st century the increase in CO2 stands a little over 45%. And moreover, the lag time to “equilibrium”–which we will never reach in reality, anyway–is, AFAIK, not well constrained.

    (Corrections from the more knowledgeable appreciated.)

    Sanity checks on the ‘not well constrained’ comment:

    1) Li et al (2013): https://link.springer.com/article/10.1007/s00382-012-1350-z

    “We integrate the coupled climate model ECHAM5/MPIOM to equilibrium under atmospheric CO2 quadrupling. The equilibrium global-mean surface-temperature change is 10.8 K. The surface equilibrates within about 1,200 years, the deep ocean within 5,000 years.”

    2) Gregory et al (2004): http://s3.amazonaws.com/zanran_storage/langley.atmos.colostate.edu/ContentPages/47804763.pdf

    “Averaged over years 1100–1200,dT(2xeff)= 4.1 ± 0.1 K (uncertainty is the interdecadalstandard deviation).” Their Figure 2 shows temperature response of several experiments plotted over 1000 years, with equilibrium still not achieved.

    (Cited as “accurate within 10%” by Li et al.)

    An important clue (I think) is given in this statement:

    “In method A, a climate model is run to a steady state with known forcing, and [alpha] is given by F/dT. This method is practicable with a ‘‘slab’’ model (an atmosphere GCM coupled to a mixed-layer ocean), because such models take only 10–20 years to reach a steady state. Coupled atmo-sphere-ocean GCMs (AOGCMs), however, take millennia, making this method computationally very expensive…”

    In other words, and as I take it, unrealistically simple models of the ocean lead to unrealistically short equilibrium times.

    3) AR5, Chapter 9 considers the question, of course, and a direct link is here: https://pure.mpg.de/rest/items/item_1977534/component/file_3040450/content

    “In CMIP5, climate sensitivity is diagnosed directly from the AOGCMs following the approach of Gregory et al. (2004).”

    Interestingly, the paper just cited! The discussion continues:

    “In this case the CO2 concentration is instantaneously quadrupled and kept constant for 150 years of simulation, and both equilibrium climate sensitivity and RF are diagnosed from a linear fit of perturbations in global mean surface temperature to the instantaneous radiative imbalance at the TOA…”

    Then ECS is contrasted with the ‘Transient Climate Response’ (TCR):

    “The transient climate response (TCR) is the change in global and annual mean surface temperature from an experiment in which the CO2 concentration is increased by 1% yr–1, and calculated using the difference between the start of the experiment and a 20-year period centered on the time of CO2 doubling. TCR is smaller than ECS because ocean heat uptake delays surface warming. TCR is linearly correlated with ECS in the CMIP5 ensemble (Figure 9.42), although the relationship may be nonlinear outside the range spanned in Table 9.5 (Knutti et al., 2005).”

    Clearly TCR more closely models the reality.

    Among many other interesting things in the chapter, there’s an apparent direct response to the question MRM posed, and which I quoted above:

    “High climate sensitivity values above 5°C (in some cases above 10°C) are found in the PPE based on HadAM/HadCM3. Several recent studies find that such high values cannot be excluded based on climatological constraints…”

    4) By the way, Knutti et al is here:

    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005GL023294

    It runs out temperature response to 2400 CE.

    Sanity check result: equilibration time is better constrained than I thought, and also longer than I remembered.

    My overall takeaway is that, yes, long equilibration times are problematic because they imply considerable uncertainty in using relatively short spans of observations (such as “20th century warming”) as a constraint on sensitivity estimates.

  50. 50
    Russell says:

    A decade ago I remarked in Foreign Affairs than mankind has already, for better or worse, altered the albedo of half the land surface of the Earth.

    It’s a relief to see the IPCC willingly expand its attention beyond the limits of fashion, for we clearly need to mitigate more than atmospheric radiative forcing.