The climate challenges that my morning toast poses

This isn’t a topic I’m particularly familiar with, but since people were commenting about the impact of climate change on agriculture, I thought I might reblog this as I think some will find it of interest.

Simple Climate

Britain's wheatfields could become even more productive as the world warms - but that will have implications for further greenhouse gas emissions and fairness to countries less well positioned. Image credit: Tim Gage used via Flickr Creative Commons license Britain’s wheatfields could become even more productive as the world warms – but that will have implications for further greenhouse gas emissions and fairness to countries less well positioned. Image credit: Tim Gage used via Flickr Creative Commons license

It may seem that nothing could be simpler than toast, but next time I see a slice pop up I’ll also see an emblem of the world’s future. That’s thanks to a UK study exploring the problems surrounding growing enough wheat for flour and other foods as the world warms and has ever more people in it. The issue is especially tangled, Mirjam Röder and her University of Manchester teammates show, as adapting farming for the future will likely increase greenhouse gas emissions, driving further warming. “Climate change and food security are two issues which can’t be decoupled,” Mirjam told me. “The same applies for mitigation and adaptation.”

Mirjam is part…

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46 Responses to The climate challenges that my morning toast poses

  1. > with worldwide productivity falling as temperatures rise

    I think this is wrong. What it probably means is, that the effects of GW will be negative on ag. However, that negative isn’t strong enough to remove the increasing trend coming from better tech. Or so I assert, if past increases are any guide.

  2. William,
    This isn’t really an area that I’m particularly familiar with. I’m hoping I might learn something through the comments 🙂

  3. Rachel says:

    My understanding is that rising temperatures up to a point (and I think we’re almost at that point) are beneficial to crops, but beyond that they have a negative impact on yields. This article in Plant Physiology, How Do We Improve Crop Production in a Warming World? says,

    With warming temperatures of 1°C to 3°C, yields at lower latitudes are predicted to decrease, although global food production is predicted to increase (Easterling et al., 2007). The IPCC projections assume that yield improvements from the latter half of the 20th century will continue into the future; however, based on historical temperature-crop yield relationships, potential ceilings to crop yields, and limitations to expansion of agricultural lands, that assumption may not be sound (Long and Ort, 2010). In fact, the relative rates of yield increase for all of the major cereal crops are already declining (Fischer and Edmeades, 2010).

    And this article from the National Bureau of Economic Research: Estimating the Impact of Climate Change on Crop Yields,

    Yields increase in temperature until about 29C for corn, 30C for soybeans, and 32C for cotton, but temperatures above these thresholds become very harmful. The slope of the decline above the optimum is significantly steeper than the incline below it.

    I’ve also read something about higher nighttime temperatures decreasing yields. Here: Rice yields decline with higher night temperature from global warming,

    Grain yield declined by 10% for each 1°C increase in growing-season minimum temperature in the dry season, whereas the effect of maximum temperature on crop yield was insignificant.

    Since I am soon to be moving to Scotland (yay!) I thought I’d have a look at the crops grown there and they include barely, wheat and oats. A simple way to reduce the greenhouse gas emissions of this sector is to reduce our consumption of animal protein. According to that link, 55% of the barley grown in Scotland goes into animal feed and so too does a proportion of the wheat although I am not sure how much.

  4. BBD says:


    I fervently hope you are correct, but it’s worth bearing in mind that past (and ongoing) increases in global agricultural productivity may not be a guide to future yields under different and changing conditions.

  5. On March 31 we will see, what AR5 WG2 tells about the food security as the almost final report will be made publicly available.

  6. BBD says:

    On the vexed question of uncertainty, there’s Gornall et al. (2010) Implications of climate change for agricultural productivity in the early twenty-first century.

    Richard Betts is a co-author.

  7. Marlowe Johnson says:

    BBD on this question I tend to take Robert Gordon’s view on this as he applies it to economic growth — we’ve picked all the low hanging fruit and there’s not much reason to expect significant future increase in yields absent some pretty significant technological breakthroughs that are deployed on a global scale. And just to be clear I doubt that GMO’s are likely to fit that bill.

    On a separate but related note, I was looking at the USDA’s long term (10 year) ag production forecast a couple days ago (available here: ) and based on their assumptions on the price projections for crude oil and oilseeds, biodiesel and renewable will be cheaper to make than diesel in less than 6 years, so maybe a little optimism is warranted

  8. I guess an issue with the possibility that we can use technology to overcome the impact of CC, is that it becomes regional. Regions that are wealthy may be able to maintain agricultural productivity through improvements in technology, but what about regions that are not? As I understand it, much of the impact will fall in these regions anyway, so it’s not clear to me that technology will be some kind of saviour (unless we suddenly become more generous in how we share our technology and how we fund technological advances in regions that are not economically strong).

  9. Steve Bloom says:

    “what about regions that are not?”

    One word: Triage. It’s their own fault for not being rich. This will get quite nasty.

  10. AnOilMan says:

    Plant growth depends on the plant. Every species is different and some have very different breathing mechanisms. Some interpret higher CO2 as death, as in a drought, so they reduce their ability to breath as well as loose water.

    This result shouldn’t be surprising as it’s the same as the oceans. Some species will thrive, however most will not, largely because of increased temperatures.

  11. Marlowe Johnson says:

    unfortunately the plants and animals that are the most adaptable are what we would consider weeds and pests. a real win-win situation for monsanto and dupont but not so much for the rest of us.

  12. BBD says:

    God it hurts, but once again, I find myself agreeing with Marlowe 😉

  13. Steve Bloom says:

    I see the current issue of PNAS has a big open-access section of papers related to this topic, the first fruits of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). The articles are all linked through a kick-off editorial.

    There appears to be much of interest, especially a paper finding, in contrast to the SREX conclusion beloved of RP Jr., that the projected increase in extreme precipitation events really will lead to more flooding.

  14. > we’ve picked all the low hanging fruit and there’s not much reason to expect significant future increase in yields absent some pretty significant technological breakthroughs

    Might be true in the West but not globally, e.g.

  15. William,
    So either that implies we’ll all be in trouble if we don’t improve technology in regions where advancements are possible, or it implies that we will be forced to invest in those regions, which could well be a good thing, or I’ve misunderstood your link 🙂 .

  16. AnOilMan says:

    William, I’m not really sure what that data measures. For all I know it measures deforestation. That would most definitely increase food production for a while. 🙂

    From personal experience all I can say is that I know Canada’s Prairie soil is really poor. It won’t support much. And I guess if you can remember the early days of climate denial, it was often thrown in our faces that northern countries would have vastly increased food production. Such claims IMO are only being made theoretically.

  17. Rachel says:

    I asked an Ag.Scientist about this and it was their view that global crop yields could be doubled for most foods not just through advances in technology but by implementing existing knowledge. This is especially so for developing countries. I haven’t got a link I can provide though, just the opinion of an expert 🙂

  18. AnOilMan says:

    Rachel, that sounds pretty theoretical. You’re talking about distributing chemicals, and mechanical equipment to third world countries. Of course that will also put all the farmers out of work because they will need scale to make it profitable. I guess I’m saying that I think its as far off as the West dealing with Climate Change.

  19. Rachel says:

    AnOilMan, yes I think he means fertilizers and weed and pest control but other things too like good agronomy which is essentially choosing the right varieties of plants and then managing them appropriately. I think there might also be other barriers to food production like conflict and war, lack of infrastructure and poor domestic agricultural policies. There are some very real gains to be made here. But this does not change the risk to food production that changing weather patterns – due to climate change – will bring.

  20. BBD says:


    Yes, that’s a view I’ve heard from tutors at Sparsholt Agricultural College which is just up the road. When asked about regional climate change later this century, they all agreed that it could be a significant brake on yield improvements. My understanding is that the mid-latitude NH is vulnerable to shifts in rainfall and crops in the equatorial band are at the edge of their thermal envelopes and can’t tolerate much higher temperatures.

  21. That's MR. Ball to you. says:

    Rachel: I asked an Ag.Scientist about this and it was their view that global crop yields could be doubled for most foods not just through advances in technology but by implementing existing knowledge.

    I’m a person with a botany degree, not an Ag scientist, but this is more or less my view. It goes along with “we can do pretty much anything if we put our minds to it” and probably more if we can convince the business world that there are jobs to be created here as well. But while they’re claiming that “climate science promotes a set of uncertain risks to justify unnecessary expenditures” as a delaying tactic, we’re getting nowhere.

    The reality is that we have a huge store of agricultural and other knowledge, and we could actively work to move desirable plant communities northward, while trying to (re-)create ecosystems that would store carbon and improve soil conditions for other types of agriculture. We could even do that and reduce our dependence on fertilizer and fuel inputs. Call it Permaculture on a large scale, if you want. It would also require a large-scale political culture change though, which I am less optimistic about.

  22. It goes along with “we can do pretty much anything if we put our minds to it” and probably more if we can convince the business world that there are jobs to be created here as well. But while they’re claiming that “climate science promotes a set of uncertain risks to justify unnecessary expenditures” as a delaying tactic, we’re getting nowhere.

    That’s been one of my issues with the climate science debate. Why don’t more people simply see it as an opportunity to both do more (develop technologies, create jobs, …) while at the same time hopefully preventing dangerous levels of warming. It seems some people think that when you spend money it simply disappears. Well it doesn’t. It may disappear from those who’d like to keep it to themselves, but it goes to others who are probably more than willing to work in order to get it and then spend it. I’m no economist, but I’m pretty sure that’s a fairly fundamental part of how an economy is meant to work.

  23. ATTP,
    The problem is that the only economic system known to work reasonably well is market economy. It’s possible to influence the markets in a beneficial way to reach desirable effects, but trying to force the markets very strongly leads to a poor outcome.

    In market economy few people or companies can afford to be ahead of their time. There are two reasons for that. One is that predicting future is difficult. Even, when the general ideas are understood well, the details are unknown. Therefore being ahead means very easily moving to a direction that’s too much off from the right one. For business that means losses. Quite a few companies have ended in bankruptcy for that reason.

    The other reason is that even views that turn out to be right in the long run may take too long to produce positive cash flow for the company to survive. (Or as Keynes said: Markets can remain irrational a lot longer than you and I can stay solvent.)

    Such considerations are, of course, the main justification for government support of R&D as well as some early investment. In the second case the result may be highly positive in the long run, but in the first even the government funds may turn out to be just wasted.

    Trying too large leaps, or trying to force progress to be faster than can be supported is inefficient. A right balance should be found, but finding the balance is mostly difficult, and getting such policies accepted that support the right balance may be even more difficult.

  24. Pekka,
    Yes, I didn’t say it was easy. Just because it’s difficult, however, doesn’t mean we shouldn’t at least try.

  25. That's MR. Ball to you. says:

    ATTP and Pekka,

    ATTP: “Why don’t more people simply see it as an opportunity to both do more”

    Pekka: “The problem is that the only economic system known to work reasonably well is market economy.”

    Pekka, this is the received wisdom, it’s not a natural law. To me it’s simply holding up another excuse for inaction. Business as usual.

    Here’s a positive example: 30 years ago, Amory Lovins (American physicist) was arguing that if you took the capital investment needed for the (then) six nuclear power plants planned or under construction in the US, and used it to pay for residential & commercial efficiency retrofits (insulation, lighting, heating) you could save an equivalent amount well before the end-of-life costs of those six plants. In the process, you would create roughly 20x the number of jobs, and most of the money would go into communities rather than the big electricity utilities. Sad to say, this never happened, but I still think it’s a workable idea, and apparently so does he.

    AnOilMan makes some great points about what we can accomplish with division of labour and effective project management in the thread next door. The amount of information and organization needed to build an aircraft carrier, a nuclear power plant, or to put a rover on Mars is inconceivable to me too, but you’re going to have a hard time convincing me that it can’t be done.

  26. Marlowe Johnson says:


    While I agree with much of what you say, IMO we aren’t even close to reaching the point where we could reasonably be accused by our descendants of going too fast, so that doesn’t seem particularly relevant to the discussion. Of course I may be wrong, but we’ll never know 😉 .

    I’d also suggest that that ‘efficiency’ in the economic sense that you imply is not the only or even the most important element that democratic societies consider when weighing various policy options for a given problem. Thankfully the world is not run by Richard Tol.

  27. BBD says:

    Who’s going to tell Richard?

  28. One thing is what we should do collectively and in general terms, but all practical action is done by someone and in a concrete way. It’s easier to agree in principle than to agree on specific policies. Policy measures like carbon tax or cap & trade encourage private action, but someone must still do the actual decision to act.

    I do support carbon taxes. They are the best choice for policy action in my view, but I’m afraid that the results will be less than many consider necessary unless the tax level is very high, and very high taxes may lead to wrong paths again. Many of the other possible decisions are less certain to lead to positive net outcome than taxes that are not too high. (Cap & trade is closely related, but less efficient than carbon taxes of comparable cost level.)

  29. Tom Curtis says:

    Pekka seems to be saying that:
    1) No economic system is better than a market economy;
    2) The market economy is causing a problem that may well be catastrophic; and
    3) The market economy cannot move fast enough to solve that problem.

    While this may merely be tragic rather than strictly inconsistent, we would be foolish to not at least challenge one of (1) or (3) in the situation. Most sensibly, we must require the market economy to move faster. If it is genuinely unable to do so, then with regret we must abandon it for an economic system that can move fast enough.

    Fortunately I think he is wrong about (3). He is merely confusing “unwilling” with “unable”.

  30. CCL’s plan is careful to gradually ramp up the revenue-neutral carbon fee, starting at $15 USD/ton of CO2. This only raises gasoline prices by about 15 cents/gallon. This small increase isn’t unusual or scary and it’s refunded to citizens anyway.

    I like CCL’s plan because it specifies that the carbon fee increases by $10 per year so in the second year each citizen gets dividends from a $25 USD/ton fee. Etc.

    I’m no economist but Dr. Shi-Ling Hsu is, and he seems to agree (see third video) that starting small and ramping up at a predictable rate will allow businesses to plan for the future.

    But we need to take that first step soon by raising the carbon fee above $0/ton, or just stop pretending we care about the future of our civilization. Because no civilization that treats its only breathable atmosphere like a free sewer will survive very long.

  31. Tom Curtis says:

    Dumb Scientist, however favourably I might view it, a flat rate dividend from a fee and dividend scheme is progressive. That is, it moves income from the wealthier members of society to the poorer members of society. That is an inevitable barrier to conservative or right wing voters and politicians. If we are serious about tackling climate change, we need to start proposing fee and dividend structures which minimize that effect. Something like a dividend proportional to the greater of income tax paid and/or social welfare payments received would do the trick. The conservatives may still not come on board, but then it will be because they object to tackling climate change rather than because our climate change solution contains further increases current transfers of wealth through taxation and welfare.

    Another alternative for power generation would be a carbon fee on emissions, with dividend to the producing companies proportional to total power from any source sold. Such a scheme would be as close to price neutral as is possible so would not require direct compensation. It is, however, limited to just one area of the economy, and perhaps difficult to expand beyond it.

  32. Lomborg says a carbon fee would harm the poor, so it can’t be progressive. That’s actually the most common reason contrarians accuse me of murder and genocide.

    A flat dividend protects the poor against higher prices, because heating/cooling/transportation costs are a bigger percentage of a poverty-level income. Ironically, some Republican members of Congress have expressed concern to me that their poorer rural constituents might not break even under a flat dividend. They were implicitly arguing for an even more progressive dividend structure.

  33. Tom Curtis says:

    Dumb Scientist, I am tempted to say that if Lomborg disagrees with me, I must be right 😉

    I in fact agree that heating/cooling/transport are a bigger percentage of poverty-level expenditure; and also that the wealthy can more easily implement measures to reduce their emissions, ie, install solar panels, improve insulation, etc. Consequently a dividend proportional to income tax/welfare receipts would be regressive in its effect. However, it will not be as regressive as the consequences of climate change. Further, while the Republican Congressman may be right in particular instances, those are exceptional cases. I do not think there can be much doubt that a flat dividend is, overall, progressive. (Lomborg’s point is based on the impact on the globally poor, not the relatively poor of Western nations, so is moot.)

    We cannot take the position that climate change is so serious a problem that we will not sacrifice any of our policy preferences to mitigate it, and expect to be taken seriously. In this case, if accepting a more regressive dividend structure will get you a strong fee and dividend legislation, with progressively increasing fees over time – that is a solid gain for the world, and even for the poor in the long term. We can then return to fighting for more equitable distribution of income/ or the ensuring that minimal needs are met knowing that we have a future in which to achieve those outcomes.

  34. “if accepting a more regressive dividend structure will get you a strong fee and dividend legislation”

    That’s a big if. Frankly, none of the objections I’ve encountered seem sincere. And I worry about what would happen when the fee started getting high enough to matter if the poor didn’t get an equal cut of the dividends. While it’s possible that the result would be better for the poor than in a world without a dividend at all, I think it’s also possible that the dividend would simply be repealed due to the public outcry. That might actually be worse.

  35. Tom Curtis says:

    Dumb Scientist, assume a fee and dividend is effective. That is, introduction of a fee and dividend over time reduces GHG emissions to zero. It follows that at that point there are no fees paid, and no dividends paid out. The entire remaining cost of the scheme is the difference in cost between generating power using fossil fuels, and that cost using what ever mix of renewables and nuclear in use at that time. At that time, there is no difference between different dividend structures. It follows that after a certain point, no matter what the dividend structure, the net cost to a particular social group will move inexorably towards the net cost with no emissions (and hence no dividend). Consequently while it is possible for a fee and dividend scheme to start out regressive and become more so over time, there is a limit on how far that can progress.

    Further, it is unlikely that a fee and dividend will become significantly more regressive than it is at the start. That is because the restriction on the poor that makes the fee and dividend potentially regressive is that they are price takers, with little ability to independently lower their emissions. That means their emissions will track downwards with that of the general electricity supply, and with a short delay, with general transport. And, of course, the emissions of general electricity supply will fall rapidly under a sensible fee and dividend scheme (and if it will not, we need a better policy in any event). For the fee and dividend to become significantly more regressive, reduction of emissions by the wealthier portions of the population must occur very much more rapidly than for the general electricity supply, which is unlikely.

  36. If Republican opposition to a carbon fee centered around the fact that CCL’s plan gives an equal share to all citizens rather than giving more of the fee to rich citizens, then I’d agree that we should pass a regressive carbon fee. I’m skeptical, though, because again most of the opposition I’ve faced from conservatives is completely different. They seem to be worried that a carbon fee will kill poor people and be siphoned off to rich people like Al Gore. I think making the carbon fee more regressive would merely strengthen their opposition, so I’m skeptical that this would help pass a carbon fee faster.

  37. Rachel says:

    I found this graph of optimum day/night temperatures for rice and wheat. For rice it’s 30/24 and wheat is 25/19.

    Rice and Wheat temperature optimums

    Source: Differences between rice and wheat in temperature responses of photosynthesis and plant growth.

  38. AnOilMan says:

    Rachel, it think that’s too narrow a view. Granted wheat and rice are the staple for the majority of the population, but humans eat more than that. Locally a few farms are growing asparagus, however their yields are 20%, that of farms in California, mainly because temperatures are too cold. So if California hits 60C+, temperatures in the Canadian Prairies would be ideal. 🙂

    Ahhhh… It was a hydroponic test. Not really relevant in the real world.

  39. Tom Curtis says:

    Dumb Scientist, I cannot speak to Republican opposition, but it is a very common charge that Global Warming is just a pretext to introduce socialism by stealth. I suspect that is a charge that resonates strongly with the Republican base. Further, I long ago learnt not to believe what politicians say, but how they act. Republicans are not concerned about the fate of the poor. If they were, they would not be Republicans.

  40. I agree that the “socialism by stealth” charge resonates strongly with Republicans because most of my family (in Louisiana and Alabama) are Republicans. I also agree that such concerns could be reduced by a regressive carbon fee. If that concern is the primary reason why we’re still treating the atmosphere like a free sewer, then I’d support a regressive carbon fee despite my misgivings.

    I just worry that this is actually another catch-22, where a flat dividend is attacked as socialist, and a regressive dividend is attacked as killing poor people.

  41. Tom Curtis says:

    “I just worry that this is actually another catch-22, where a flat dividend is attacked as socialist, and a regressive dividend is attacked as killing poor people.”

    I think that is a very fair concern. Working from “believe what they do, not what they say”, Republicans will not accept fee and dividend under any dividend structure. Nor will they accept any other method of putting a price on Carbon, or of regulating Carbon emissions. However, when all proposals for a price on carbon result in a clear income shift, we are making life to easy for them. We should at least propose a range of dividend structures and invite them to negotiate the final structure they think is best. That will at least make their refusal to do so a clear rejection of action on GHG emissions. They will not be able to hide behind claims of “socialism by stealth” or “concern for the poor” when they are presented with a flexible proposition with room to negotiate on those concerns. (I should say, “they will not be able to rationally hide”, or course. Denial is the gift that keeps on taking.)

  42. We should at least propose a range of dividend structures and invite them to negotiate the final structure they think is best.

    That’s a wise course of action, and one which CCL has been trying to implement for years. Sadly, no Republicans currently in Congress have accepted our invitations.

  43. Steve Bloom says:

    In my experience the “socialism” charge is mainly a way of avoiding having to think about things.

  44. Tom Curtis says:

    Steve Bloom, you only say that because your a watermelon – green on the outside and red on the inside 😉

    I, in contrast am a sort of pinkish brown on the outside, and red on the inside. I think that is because I am a (caucasian) human.

    I have to wonder what sort of weird aliens Republicans are, given that by their own testimony they are not red on the inside at all.

  45. AnOilMan says:

    Steve Bloom, Tom Curtis,

    In arguing with conservatives, I’ve found it useful to argue more conservatively about everything they say. Its not like its hard, because they are almost always supporting some sort of Corporate Welfare. (Free money for big business.) For instance there were many arguments over oil tankers in BC. The usual enviros versus jobs, blah blah blah. Then I pointed out that all oil tankers are subsidized in Canada. They only carry $35 million in insurance, and that leaves the tax payers on the line for the rest in the event of an accident. I saw people arguing against enviros suddenly switch gears to anti-tanker. This is a key element of the BC government’s opposition at this time.

    Bob Altemeyer’s Book, The Authoritarians, goes a long way to discerning what is going through those little minds; ( I just so happens that Authoritarian supporters happen to occupy what we North America call the Right. There are a lot of conservative people out there who are very reasonable and understanding. But they aren’t the problem.

    This may not be the case in other parts of the world. But I believe it is on the rise because.. i dunno… they take money from anyone to get what they want. The Koch brothers created and funded the Tea Party to blindly argue for what they want (they recently shutdown the US government over Obama Care);

    I guess I’m saying that there are a lot more shades of Red in those Republicans. Many of the conservative stripe have valid concerns. Too bad about the rabid attack dogs running the show.

  46. Rachel says:

    A paper published today in Nature Climate Change says Climate change will reduce crop yields sooner than we thought.

    A study led by the University of Leeds has shown that global warming of only 2°C will be detrimental to crops in temperate and tropical regions, with reduced yields from the 2030s onwards.

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