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Global Warming To Reduce Wheat Yields (According To Models!)

November 23, 2016

By Paul Homewood 




Today’s dose of grant funded junk science!




The potential impact of global temperature change on global crop yield has recently been assessed with different methods. Here we show that grid-based and point-based simulations and statistical regressions (from historic records), without deliberate adaptation or CO2 fertilization effects, produce similar estimates of temperature impact on wheat yields at global and national scales. With a 1℃ global temperature increase, global wheat yield is projected to decline between 4.1% and 6.4%. Projected relative temperature impacts from different methods were similar for major wheat producing countries China, India, USA and France, but less so for Russia. Point-based and grid-based simulations, and to some extent the statistical regressions, were consistent in projecting that warmer regions are likely to suffer more yield loss with increasing temperature than cooler regions. By forming a multi-method ensemble, it was possible to quantify ‘method uncertainty’ in addition to model uncertainty. This significantly improves confidence in estimates of climate impacts on global food security. 




Meanwhile, back in the real world:



  1. Graeme No.3 permalink
    November 23, 2016 11:06 pm

    Models don’t carry much weight, do they?

    • catweazle666 permalink
      November 24, 2016 12:15 am

      “The data doesn’t matter. We’re not basing our recommendations on the data. We’re basing them on the climate models.”

      ~ Prof. Chris Folland ~ (Hadley Centre for Climate Prediction and Research)

      • Gerry, England permalink
        November 24, 2016 1:37 pm

        ‘But just in case, we will fiddle the data to reduce unhelpful warm periods, use contaminated temperature stations and grid to the max.’ An aside was overheard that said ‘and we have to get those damn satellites.’

    • tom0mason permalink
      November 24, 2016 10:25 am

      As shown recently in the USA —

      Observation Trumps computer models!

  2. November 23, 2016 11:09 pm

    Reblogged this on Climatism and commented:

    If “Global Warming” is the demon it appears its evil byproducts – heat and CO2 are increasing (massively), not decreasing wheat crops in Australia alone…

    “Australian Bureau of Agricultural and Resource Economics and Sciences tips record national crop”

    What planet do these doomsday “scientists” live on?

    Sounds a lot like the planet of computer models, government grants and ideology.

    “Time To Drain The monopolistic climate funding Swamp.”

  3. November 24, 2016 1:53 am

    The key is to leave out CO2 fertilization effects. CO2 is positive and high temperature is negative. But the good outweighs the bad and of course you can grow crops further north

    In soybeans the seed rate is directly proportional to CO2 levels
    Growth rates

    During the linear phase of vegetative growth after full ground cover is reached, the growth rates of plants exposed to a range of CO2 concentrations varied from 5.0 to 20.7 g/m2/d for exposures from 160 to 990 m mol/mol (Allen et al., 1991). The total final dry weight ranged from 12.88 to 39.12 g/plant, and final seed weight ranged from 5.77 to 17.85 g/plant for CO2 treatments ranging from 160 to 660 m mol/mol.

    the same study has lots of actual data.

    So increasing CO2 increases crop yield based on lab tests and field tests also show a historical rise in yield. The forecast increase in temperature has not occurred so there has been a measurable direct benefit from the increase inc CO2 and no downside. The science is clear.

  4. Andy DC permalink
    November 24, 2016 2:01 am

    There is also a very strong correlation between atmopheric CO2 levels and corn yields in the US corn belt. There has been only one significant heat/drought reduction of the US corn crop during the last 28 growing seasons. There were four such reductions during the 1930’s alone. Apparently evil CO2 has been great for the corn crop! But you could never get an alarmist to admit a potentially beneficial result from so-called climate change.

  5. Stephen Lord permalink
    November 24, 2016 2:05 am

    They were honest and clearly stated their methodology. They just left out CO2 fertilization effect because of course it overwhelms the temperature effect which may not occur anyway. It seems the CO2 effect would be at least a 30% increase in yield so 30-4 is 26%. So headline should be global warming could reduce yields by a small amount but CO2 fertilization will significantly increase them.

    Here we show that grid-based and point-based simulations and statistical regressions (from historic records), without deliberate adaptation or CO2 fertilization effects, produce similar estimates of temperature impact on wheat yields at global and national scales.

  6. tom0mason permalink
    November 24, 2016 4:03 am

    I wonder how the researchers square the circle of the few results from these studies that show that wheat does very well with elevated CO2.

  7. November 24, 2016 7:08 am

    The amount of money that is wasted based on using the results of models which are known to have no validity must be humongous.

  8. NeilC permalink
    November 24, 2016 8:03 am

    They obviously never did O level biology. They may have learnt about something called photosynthesis sarc/

  9. tom0mason permalink
    November 24, 2016 9:58 am

    As Richard Feynman explained so well, pseudoscience has all of the attributes of scientific type methodologies with none of the rigor. Pseudoscience offers instant answers with none of that complicated validation or verification against the observed evidence.
    Pseudoscience is never unsure, uncertain, or unknowing.
    Pseudoscience is a triumph of the ego and hubris over observation.

  10. Gerry, England permalink
    November 24, 2016 1:42 pm

    Another case of conclusion first and ‘proof’ second? At least 97% of these papers work this way round.

  11. November 24, 2016 2:25 pm

    Yesterday, Rush Limbaugh gave the skinny on Trump’s meeting with the NY Times. The transcripts show a different meeting than reported by the Gray Lady. Below is from Rush’s transcript:

    “Trump was by turns solicitous, argumentative, evasive, joking and defiant with the nation’s most important newspaper, which has been among Trump’s top targets,” and they go on to describe some of the things that Trump may have changed his mind on — and he didn’t. If you read the transcripts, you can see clearly Trump spoke to them like he speaks to everybody. “Well, I’m looking into it.” “It could be.” “You know what? I don’t want it to have bad effect on business.” (Trump refuses to accept their premise).

    “Look, you want to talk about climate change? How about all those emails from East Anglia?” He mentioned this to ’em. I know they’ve been faking the data. The Times doesn’t publish that. doesn’t publish them. If you get the transcript of Trump’s interview, you find he threw it right back in their faces. But you’re not seeing that. You’re seeing, “Trump waffles,” “Trump caves on climate,” and climate change is big to them, folks. Climate change… If they could force Trump to capitulate on climate change that would almost be the equivalent of them winning the election.

    Because climate change has all the elements they believe in: Big Government, high taxes, limited liberty and freedom on the part of the people. The United States is guilty, the United States is to blame, the United States must bear the brunt of punishment. Everything that the left thinks about this country and everything they want to happen to this country is encapsulated in their beliefs and climate change.

    Donald Trump did not change his position or waffle. He did not accept the premise of man-caused climate change, he reminded Arthur Schultzberger who was bleating about storms around NYC: “Arthur, there have always been storms.” I was impressed that Donald Trump knew about the “Climategate” of East Anglia and threw it back in their face.

  12. Steve McIntyre permalink
    November 25, 2016 1:14 am

    I spent some time looking at similar claims by Lobell and Field. I meant to write it up because my results were amazing: in Lobell’s case, he did a regression against two highly correlated terms, one of which was temperature. The negative regression coefficient was an artifact of multicollinearity, not anything botanical. I suspect it’s the same with this new one.

  13. permalink
    December 2, 2016 10:46 am


    You have prompted me – many times – to think wider about what is going on with the world. I think we might agree that some kind of change is afoot. Peculiarities with climate and temperatures may be happening. Fir the sake of this note can we assume so?

    “They” are blaming the atmosphere for causing greenhouse effects etc. But suppose it is something else completely. You suggested sub-sea geothermal activity may be warming western Antarctica etc. Let us build on that. Suppose the Earth’s core is either warming up or, that the centre of heat of the crust is moving. Either of these will modify the surface temperature causing some of the effects we think we are seeing.

    Most surface warming will be at thin points in the crust – bottom of the sea. You have proposed one. How about the bottom of the Arctic Sea? If the hot centre has moved north a bit the latter effect may have happened melting the sea ice – with the opposite effect under Antarctica causing the reported ice build up and falling temperatures there?

    Iceland is clearly a geothermal hot spot – it is amazing it has ice at all – so a marginal crust temperature rise will easily melt its glaciers and ice cap. A northern shift of core hot centre will do that.

    So, why would the core not move around over the centuries – seems obvious to this Engineer that it would. It seems obvious that the hot hub will not be a neat sphere but maybe sausage shaped or even very complex shaped. This could give your hot spot in the Pacific at the same time as heating the north pole.

    Is anyone measuring temperatures down mines or on the deepest sea bed? Is there any evidence of increased of volcanic or earthquake activity? Is anyone looking for anything that could identify hot core relocation in any way?

    My other reason for writing is the Sir David Attenborough in his new series said that the Mongolian Plateau was warming faster than anywhere on Earth (second programme). First, is this true or is it BBC-prop? Second, if it is could it be that this high plateau could actually be a zone of thin crust beginning to be cooked from below? It looks a very geothermal unstable area to me – like Iceland?

    Any thoughts? If this is right it will make the Academic Cardinals in their sponsored Curia look very stupid indeed. This simple Engineer has always believed in looking for other reasons not just the obvious, when problems arise.

    Very best wishes

    Malcolm (Mike) Bell 9 Foxhill Green Weetwood Leeds. UK LS16 5PQ

    Tel 07802 920096


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