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Wheat Yields To Fall (As They Continue To Rise)!

October 2, 2018

By Paul Homewood


Silly season continues at the BBC:



Insects will be at the heart of worldwide crop losses as the climate warms up, predicts a US study.

Scientists estimate the pests will be eating 10-25% more wheat, rice and maize across the globe for each one degree rise in climate temperature.

Warming drives insect energy use and prompts them to eat more. Their populations can also increase.

This is bound to put pressure on the world’s leading cereal crops, says study co-author Curtis Deutsch.

"Insect pests currently consume the equivalent of one out of every 12 loaves of bread (before they ever get made). By the end of this century, if climate change continues unabated, insects will be eating more than two loaves of every 12 that could have been made," the University of Washington, US, researcher told BBC News.

Prof Deutsch, Joshua Tewksbury and colleagues have conducted a study on a global scale and looked at three different grain crops that are staple foods for billions of people.

The study, in the journal Science, uses data from across the globe to make a mathematical prediction that links the response of insects to temperature with the damage that is done to crops when the climate warms up.

Guy Poppy, who is Professor of Ecology at University of Southampton, UK, and works on food security said: "It is a novel piecing together of several pieces of a jigsaw".

The team put laboratory data from 38 insect species into the mathematical model. They looked to see how the energy use and growth responses of these insects to temperature might affect future crop losses.

There is already reckoned to be a direct effect of climate change on crops, with yields declining by about 5% for every one degree increase in temperature.

That loss will be 50% higher because of insect damage, said Prof Tewksbury from the University of Colorado Boulder, US.

So, this new research suggests the action of pests will accelerate temperature-induced impacts.

Which regions would be affected?

As the temperature rises insect populations grow and they eat faster. Prof Tewksbury added: "All of that adds up to bigger eating machines particularly in the temperate zone, like in the bread basket of Europe or in the corn belts of the US.

"In many European countries we’re predicting 50-100 % increases in the impact of pests on crops."

This could mean total losses in European wheat yield of around 16 million tons due to pests.

But in the tropics, insects are already closer to the optimal working temperature and a rise in temperature is actually likely to start limiting populations.

This would lead to fewer insects and fewer crops being damaged.

How will things play out?

Some of the world’s most productive regions of grain production are in the temperate zone and at risk, including US, France and China.



Meanwhile back in the real world:






  1. Lance permalink
    October 2, 2018 2:49 pm

    well here in Alberta….crops are being flattened by heavy global warming…about a foot here in the Calgary area alone…

  2. October 2, 2018 2:55 pm

    Climate impacts research is a wild and crazy thing.

  3. Ian Magness permalink
    October 2, 2018 3:39 pm

    What an absolute pile of steaming, modelled, delusional rubbish! Wrong on every level from non-declining wheat yields, through the greening effects of the magic molecule to the mitigating effects of pesticides and crop science evolution – and that’s before you even get around to examine whether global warming is happening to any degree material to plant growth.
    Dear me!
    Zero points out of ten.

  4. David Parker permalink
    October 2, 2018 3:51 pm

    below is data from the UK Agriculture & Horticulture Development Board Wheat growth guide 2018.

    Carbon dioxide: Atmospheric carbon dioxide is about 400 parts per million (ppm) and is increasing at about 21ppm per decade. In this range, crop growth relates almost directly to carbon dioxide concentration, so atmospheric change is increasing growth by about five per cent per decade. Variation in carbon dioxide concentrations is not significant on a regional or seasonal scale.

  5. Dr Alex Emodi permalink
    October 2, 2018 3:58 pm

    The sad truth is that all insects are in decline along with all the birds that eat them, so anything that would help reverse the decline of insects should be welcomed. Other than that it’s just another isolated piece of tomfoolery.

    • October 2, 2018 4:15 pm

      Quite right. Apparently the researchers haven’t been out in the field – the wheat field – recently. If they had, they would have observed fields that are all but sterile, where there is exactly one species of plant (the crop) and around about zero insects and zero birds. Yields have gone up and up because (in addition to fertiliser etc) the insects’ share and the share lost to weeds is now zilch. As you say, no pests, no weeds, no insects eating those weeds, no birds eating those pests or weed-eating insects. The result is countryside like desert. In theory such yields should leave space for nature elsewhere – but I’ve yet to see that happen at least in the UK.

      A little-remarked fact is just how rare a lot of plant species are that were formerly considered weeds.

      Pity that some prefer to make predictions based on an entirely virtual world. :/

      • John Palmer permalink
        October 3, 2018 8:12 am

        Way back in my youth- 40+ years ago we were always complaining about bugs on the windshield etc as we had constantly to be clearing them off.
        I now live in a ‘big-farm’ rural area and scarcely have to think about this issue.
        Very sadly there ain’t any bugs worth talking about.

  6. Phoenix44 permalink
    October 2, 2018 4:22 pm

    Why on Earth do they need a model?

    They have made a series of assumptions that can only result in their “answer”.

    “The model only reflects whatever spurious assumptions are put into it. Starting with the opposite assumptions would generate the opposite result. This is no route to a scientific finding.”

    • Curious George permalink
      October 2, 2018 4:59 pm

      It is a mighty model. It predicts what might happen.

    • martinbrumby permalink
      October 3, 2018 8:54 am

      Ah yes, Phoenix44.
      But it is precisely the route to a psuedoscientific funding.
      Fame, fortune, taxpayers’ paid visits to conferences in exotic vacation locations, promoting far-left greenie politics, what’s not to like?
      The real scientists have developed GM crops and are working to render mosquitoes sterile.
      Of course, our Beloved Leaders will pour taxpayer’s gold over the former team and attempt to shout down the latter.

  7. George Lawson permalink
    October 2, 2018 5:44 pm

    Do the grant givers ever look at the results of the research results for which the grant was given? What a waste of money this grant was. It is time that the grant distributors looked more carefully at the utter waste of the money they are distributing on many, almost laughable projects. They should ensure that the money is used instead on genuinely needed serious research subjects, such as medical and social projects,.and not on the increasing number of useless, money grabbing research projects we are now seeing. .This might then lead to the cycle of eco stupidity to be tamed a little.

    • John Palmer permalink
      October 2, 2018 6:57 pm

      ….and who’s money is it that’s being thrown at this pseudo-scientific garbage?
      Well.. guess who’s!
      And there I was thinking that it’s just that Corbynist Government money-tree stuff!

  8. Joe Public permalink
    October 2, 2018 5:54 pm

    Just what is the problem?

  9. tom0mason permalink
    October 2, 2018 6:54 pm

    Yes more pests to eat into our crop of observed and verified science.

    The pest IS Prof Deutsch, Joshua Tewksbury and colleagues along with the symbiot Guy Poppy, Professor of Ecology at University of Southampton, UK.
    These folk, and many ‘scientists’ like them, are reducing science to an unimaginative alarmist fantasy-land, where computer generated models trump rigorous field work, with results that are prescribed before any tests are run.

    Good field work, with verified observations and careful measurements, appear to be a thing of the past as the digital fantasy world of virtual reality science takes over.

    Paraphrasing Churchill —
    “Never in the field of human science has so much been extrapolated from so little.”

  10. Dave Ward permalink
    October 2, 2018 7:37 pm

    “Insect pests currently consume the equivalent of one out of every 12 loaves of bread (before they ever get made)”

    And how many “loves of bread” are not made because of crops being diverted to make Bio-Fuels?

  11. swan101 permalink
    October 2, 2018 7:40 pm

    Reblogged this on UPPER SONACHAN WIND FARM.

  12. October 2, 2018 8:42 pm

    yields declining by about 5% for every one degree increase in temperature.

    How many one degree increases are they expecting to get?

    • dave permalink
      October 2, 2018 10:06 pm

      UAH analysis of the satellites shows the global average figure for the lower troposphere brightness-temperature anomalies down again in September, to a mere + 0.14 C.

      I find it truly baffling that so much incessant discussion goes on about the effects of global warming, when it stopped twenty years ago. How can you have an effect without a cause?
      It is as if people huddle in a broom closet, looking for evidence of whether it is raining or not. I say, “Open the bloody door! and look!” Only, these people are so far along the path of literal madness, that they have what old- fashioned psychiatry bluntly called called ‘hysterical blindness.’

  13. October 3, 2018 2:05 am

    As Monty Pytjon said…it’s only a model

  14. October 3, 2018 1:26 pm

    Increased temperature will increase crop yields. Also since they are worried about CO2, the increase in CO2 will increase crop yields. If there is an increase in herbivores, there is also an increase in herbage.

  15. ellyssen permalink
    October 3, 2018 4:58 pm

    “There is already reckoned to be a direct effect of climate change on crops, with yields declining by about 5% for every one degree increase in temperature. That loss will be 50% higher because of insect damage, said Prof Tewksbury from the University of Colorado Boulder, US.”.
    Ok, I reckon I am confused. 5% for every degree, so does the 50% loss mean 10 degrees of temperature rise or 7.5 percent for every one degree? I am not being sarcastic, I do not know if I am interpreting it correctly. Any input folks?

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