Study: climate change accounts for only 1/3 of crop yield variation

From the University of Minnesota:

When it comes to variations in crop yield, climate has a big say

Discovery of the huge but varied role of climate change in food production provides valuable insights for preparing for future conditions

The connection between climate and yield variability differs around the world. It is strongest in the red areas and weakest in the light green and gray areas. Credit University of Minnesota Institute on the Environment

The connection between climate and yield variability differs around the world. It is strongest in the red areas and weakest in the light green and gray areas.
Credit
University of Minnesota Institute on the Environment

What impact will future climate change have on food supply? That depends in part on the extent to which variations in crop yield are attributable to variations in climate. A new report from researchers at the University of Minnesota Institute on the Environment has found that climate variability historically accounts for one-third of yield variability for maize, rice, wheat and soybeans worldwide — the equivalent of 36 million metric tons of food each year. This provides valuable information planners and policy makers can use to target efforts to stabilize farmer income and food supply and so boost food security in a warming world.

  • The work was published today in the journal Nature Communications by Deepak Ray, James Gerber, Graham MacDonald and Paul West of IonE’s Global Landscapes Initiative.
  • The researchers looked at newly available production statistics for maize, rice, wheat and soybean from 13,500 political units around the world between 1979 and 2008, along with precipitation and temperature data. The team used these data to calculate year-to-year fluctuations and estimate how much of the yield variability could be attributed to climate variability.
  • About 32 to 39 percent of year-to-year variability for the four crops could be explained by climate variability. This is substantial — the equivalent of 22 million metric tons of maize, 3 million metric tons of rice, 9 million metric tons of wheat, and 2 million metric tons of soybeans per year.
  • The links between climate and yield variability differed among regions. Climate variability explained much of yield variability in some of the most productive regions, but far less in low-yielding regions. “This means that really productive areas contribute to food security by having a bumper crop when the weather is favorable but can be hit really hard when the weather is bad and contribute disproportionately to global food insecurity,” says Ray. “At the other end of the spectrum, low-yielding regions seem to be more resilient to bad-weather years but don’t see big gains when the weather is ideal.” Some regions, such as in parts of Asia and Africa, showed little correlation between climate variability and yield variability.
  • More than 60 percent of the yield variability can be explained by climate variability in regions that are important producers of major crops, including the Midwestern U.S., the North China Plains, western Europe and Japan.
  • Depicted as global maps, the results show where and how much climate variability explains yield variability.

The research team is now looking at historical records to see whether the variability attributable to climate has changed over time — and if so, what aspects of climate are most pertinent.

“Yield variability can be a big problem from both economic and food supply standpoints,” Ray said. “The results of this study and our follow-up work can be used to improve food system stability around the world by identifying hot spots of food insecurity today as well as those likely to be exacerbated by climate change in the future.”

###

Advertisements

109 thoughts on “Study: climate change accounts for only 1/3 of crop yield variation

  1. Global annual production of maize, rice, wheat and soybean is about 2,400 million mt. The annual variability caused by climate is 36 million mt. or 1.5%. Is that significant? They say so but I have no objective way of evaluating that.

    • My first job , so many years ago, was with a Govt Agricultural Lab that often dealt with the problems of ex- colonial nations such as India . The senior scientists there told us that one of the main food problems in tropical and semitropical countries in the developing world was not yield , increased enormously by the new varieties , but long term storage of foodstuffs. In the 60s/70s it was estimated that as much as 1/3 of the stored food in India was lost to rats, mice , monkeys etc as well as fungal disease. One of the latter , caused by Aspergillus , caused many deaths through the formation of carcinogenic metabolites , for which it was our job to establish simple tests .
      I am sure that the problem is much better now , not least because the UK Govt set up a complete Res lab to tackle the problem of tropical food storage, as part of a Govt initiative to aid Commonwealth countries , but losing just 1.5% to climate change seems a very minor problem to losing 33% to animal and fungal attack and surely not beyond the wit of man , and woman , to counteract. .

      • Last I heard (and this was some years ago) refrigerated trucking had helped some. However, bureaucratic red-tape often tied up the trucks beyond the use-by date for the food contained therein. Two steps forward and one step back.

      • My uncle was and agricultural research scientist who spent time in India in the 1970s. He was so dismayed at the food losses to various creatures that he cut his stay short. He said they didn’t need his kind of expertise. Maybe that has improved now?

      • As of 2012 when Gaia’s Limits was published, India was losing 7-10% of its wheat to spoilage (mold, vermin, in that order), and up to 25% of its perishable produce (e.g. onions, tomatoes, melons) from inadequate transportation infrastructure, cold storage, in that order.
        But solving those problems completely would not make India self sufficient for more than another decade. Yields of important Indian staples (green revolution wheat (Nobel winner Borlaug’s semi-dwarf rust resistant), pulses, and potatoes were illustrated) have been plateaued for all of this century, mostly for reasons having to do with the inherent biology of improving cultivar yields (food mass to necessary plant mass) and the Indian climate. Irrigated land has plateaued and some is being poisoned by salt buildup, a loss of now up to 5%/year depending on where (worse in northern India). Arable land has plateaued, and has declined by half per capita since 1960 to levels (0.16 hectare/person) below what FAO says (0.21 hectare per person) are the minimums to produce a healthy diet. Yet to maintain India’s present (inadequate) caloric intake, and assuming no further iincrease in meat consumption, India will need to expand domestic food production by more than 60-70% by 2050 IF India meets the UN projections for slowing population growth before then. So far, it isn’t. One can foresee a big crackup coming in a couple of decades. The solution will be either massive food imports that India cannot now afford, or famine like that in the 1960s which is estimated to have taken 60 million Indian lives in about 2 years. Except this time with no possibility of relief. The alternative of several hundred million Indians migrating to food surplus places like North and South America is implausible. India is simply too big for the Irish potato famine solution. An example of why the book was ttitled Gaia’s Limits. Bit of a data slog through a lot of obscure stuff. India is a particularly grim case because its scope and scale and demographics.
        China, interestingly, is not a real concern with respect to domestic calory productionin 2050–if they can curb their drift toward increased meat calories as their wealth grows. So far, that’s not happening either.
        Globally, neither food nor water is the shoe that pinches first except on a very regional basis, like in India. Those that disagree might want to read the book before screaming Paul Ehrlich and Club of Rome were wrong. Agreed, they sure were. But every species in every environment eventually reaches its carrying capacity. The most interesting question is whether that carrying capacity is reached as a soft or hard limit. There, folks do IMO have some choices to make.

    • 1.5%? They say 1/3. But somehow they have managed to make it sound negative. The reality is that world food production has climbed pretty steadily and very significantly for several decades, and if “climate change” has been responsible for 1/3 of that then it is very beneficial indeed.
      For anyone that doesn’t get it, please note that “very beneficial indeed” refers to a good thing not a man-made disaster.
      Unfortunately my gut feeling is that they have overstated the case, and that while “climate change” is beneficial, it may not be quite as beneficial as they make out.

      • A lot of people seem to be misreading this. One-third of the VARIABILITY is allegedly explained by CC, not 1/3 of production.
        BCBill is correct — this says climate variability affects world food production by a percent or two.

      • Small problem : annual variability is weather not climate. If it’s climate as they claim then it applies to the longer-term trend. Somewhere along the line, one has to reinterpret what they’ve said, to make it work. I’ve gone one way, others have gone other ways. Between us we’ve hopefully got it covered…..

      • Global food losses due to lack of refrigeration is a strong argument to provide cheap and abundant energy to developing countries. If fossil fuels are the answer then so be it. The biosphere has responded in a positive way to increased co2. The Sahel has also been greening during our time of inclement climate.
        Is it just possible that global warming of 2C might be net beneficial during the rest of this century? I don’t know.

    • BCBill, I think your math is off. They indicate about 1/3 of the variability is due to climate, based on a sample — not the entire global production.

      • See talldave2 above. They give quantities for the what the 1/3 of the variability constitutes, i.e., 36 million mt. The world produces about 2,400 million mt of those commodities per year. As soon as I started reading the article I noticed the failure to report the amount as a proportion of production. That usually means there is a reason for not reporting that most obvious statistic.

      • Seems someone is not actually reading. See the word “worldwide” in the text?
        climate variability historically accounts for one-third of yield variability for maize, rice, wheat and soybeans worldwide — the equivalent of 36 million metric tons of food each year.

    • And they are using year to year variations in temperature & precipitation related to crop production. This is not climate change this is year to year variability due to weather. Had they compared 1979 to 2008 production and corrected for all other variables (new varieties, fertilizer rates, and ha of crops planted), then they would have had production data at the beginning and end of one 30 year period used to define climate for that period. In short this is a study of year to year weather variations on crop productions–not climatic variations.

    • If they have, as seems to be the case, ignored CO2 levels and the effect they have on crop growth and yield then their study is meaningless.

    • I wonder if they factored in the lost food production from climate change policies – switching from food to bio-fuel production ? Probably not ….. for too many warmists the odd million deaths a year from starvation seem to be a small price to pay for replacing fossil fuel with biofuel made from much needed food .

    • The research team is now looking at historical records to see whether the variability attributable to climate has changed over time — and if so, what aspects of climate are most pertinent.

      If bad climate means yields go down in the US then is it possible that yields will go up in Canada? What about northern Europe and mid to northern Russia and China?
      Historically what will people in 2030 see during our time of climate panic? We have just come out of the ‘hottest decade on the record’ and last year was the ‘hottest year evaaah’. What are the results?
      FAO – 11/12/2014
      World cereal production in 2014 to surpass the record in 2013
      “World cereal production in 2014 is forecast at a new record of 2 532 million tonnes (including rice in milled terms), 10 million tonnes higher than last month’s forecast and 7 million tonnes (0.3 percent) above last year’s peak.”
      http://www.fao.org/fileadmin/templates/worldfood/images/home-graph_4.jpg
      Here is another lesson from history. Below are some of the effects of the Little Ice Age from the peer review.
      We had crop failures, hunger, mass migration, epidemics, great storms in the North Atlantic, Europe wide witch hunts, endemic Malaria in England & part of the Arctic Circle, higher wildfire frequency in circumboreal forests, strong droughts in central Africa (1400–1750), social unrest in China, dead Central American coral reef, century-scale droughts in East Africa, large increases in flood magnitude (upper Mississippi tributaries), environmental and economic deterioration in Norway, decline in average height of Northern European men, climate became drier on the Yucatan Peninsula, sudden and catastrophic end of the Norse Western Settlement in Greenland, River Thames freeze-overs, agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century.

      • Here are the effects of another warm period in the most populated region, the northern hemisphere.
        Here is Dr. Michael Mann’s paper.

        Medieval Climatic Optimum
        Michael E Mann – University of Virginia, Charlottesville, VA, USA
        It is evident that Europe experienced, on the whole, relatively mild climate conditions during the earliest centuries of the second millennium (i.e., the early Medieval period). Agriculture was possible at higher latitudes (and higher elevations in the mountains) than is currently possible in many regions, and there are numerous anecdotal reports of especially bountiful harvests (e.g., documented yields of grain) throughout Europe during this interval of time. Grapes were grown in England several hundred kilometers north of their current limits of growth, and subtropical flora such as fig trees and olive trees grew in regions of Europe (northern Italy and parts of Germany) well north of their current range. Geological evidence indicates that mountain glaciers throughout Europe retreated substantially at this time, relative to the glacial advances of later centuries (Grove and Switsur, 1994). A host of historical documentary proxy information such as records of frost dates, freezing of water bodies, duration of snowcover, and phenological evidence (e.g., the dates of flowering of plants) indicates that severe winters were less frequent and less extreme at times during the period from about 900 – 1300 AD in central Europe……………………
        Some of the most dramatic evidence for Medieval warmth has been argued to come from Iceland and Greenland (see Ogilvie, 1991). In Greenland, the Norse settlers, arriving around AD 1000, maintained a settlement, raising dairy cattle and sheep. Greenland existed, in effect, as a thriving European colony for several centuries. While a deteriorating climate and the onset of the Little Ice Age are broadly blamed for the demise of these settlements around AD 1400,
        http://www.meteo.psu.edu/holocene/public_html/shared/articles/medclimopt.pdf

  2. What was the estimated increase in food production because of increased CO2 ? Vegetation that is no longer on the edge of CO2 starvation mean very large increases in growth, this is a well known and experimentally proven (not modelled). CO2 injection into hot house operations is standard practice to increase yields.

    • Sun Spot
      What was the estimated increase in food production because of increased CO2 ? Vegetation that is no longer on the edge of CO2 starvation mean very large increases in growth, this is a well known and experimentally proven (not modelled). CO2 injection into hot house operations is standard practice to increase yields.

      See http://www.co2science.org for far more details, but ALL plant life on earth is growing 12% to 27% faster, higher, deeper, greener and more drought resistant because of the recent CO2 injection into the atmosphere from 280 ppm to today’s 400+ ppm. exactly how much each plant species is improving depends on the kind of plant (Type 1, Type 2, Type 3, etc.) but ALL are growing faster.
      More food, more fodder, more feed, more farms, more fuel (if you burn wood or plant matter) .. What’s not to like?

      • What’s not to like? I don’t think you’re factoring in that global warming will awaken a giant fire-breathing monster lizard that will reek havoc across gaia. /s

      • In addition to the settled science on fire-breathing monster lizards and giant mutant space goats, it is also well-established that warmer temperatures lead to colder temperatures.

    • in modern agricultural systems with plenty of water and nutrients and optimized cultivars, CO2 is the limiting production factor. However, many agricultural operations (such as in the developing world – Africa mostly) CO2 is not the limiting factor. So let’s not extrapolate greenhouse data to the real world.

    • You beat me to it.
      About 32 to 39 percent of year-to-year variability for the four crops could be explained by climate variability.
      Year to year variability absolutely is weather, not climate. They’re taking known agricultural research and trying to dress it up as climate change research. Further, I’ve no idea how they could actually separate climate factors in the first place. Over the last century we’ve seen major changes in farming practices ranging from specific strains grown (many of those developed for specific climates!), low till or zero till, no more stubble burning, herbicides, pesticides, even treatments to initiate ripening to control harvest time. How would you possibly separate out all these (and other factors) from changes of a few tenths of a degree over a century?
      But hey, I’m OK to take their word for it. The converse of their statement is that 2/3 of crop variability is not due to climate, it is due to factors under our control. Which is why crop yields are the highest they have ever been. They are tacitly admitting that our ability to adapt trumps climate variability (and hence the need to mitigate) by a wide margin.

      • I’ve said this many times here: “The single biggest factor in crop yield is water”. Specifically, insufficient water reduces yields. It’s why humans now sequester ~50% of rainfall.
        No surprise that peasant agriculture is less affected; we knew that 30+ years ago. Traditional crop varieties don’t yield as much as under ideal growing conditions as more modern high yield varieties. However, modern high yield varieties are far more sensitive to water deficit. Thus traditional varieties will outyield modern varieties when conditions depart significantly from optimum.
        The economic impact of this is rarely considered by armchair pundits. If you have higher yield when conditions are optimum, that is when prices are low because there’s more tonnage, you don’t necessarily make very much money from your extra tonnage. Conversely, if you have a higher yield when growing conditions are less than optimum, you will likely make more per tonne.
        The financial outcome of course depends a great deal on how much grain is stockpiled, government interventions of various sorts, etc. Ceteris paribus and all that…

      • There are other things outside of our (complete) control, such as pests, which may be directly related to climate. I also suspect there are many aspects of climate (or weather) that they did not consider in their analysis, such as the timing of rains, and thus weather/climate is actually responsible for more than 1/3 of the variability. Not sure, though, as I haven’t read the paper.

      • Barry
        Pests are related to local conditions in a particular year. That’s weather, not climate. For me this was the “year of the cutworm”. I suspect this was due to a marked decline in the small bird population that usually manage to control the moths whose larvae constitute cutworms. The decline in small birds is likely due to the egg-eating habit of kookaburras whose numbers have been on the increase.
        Kookaburras are a protected species even though they are not native to Tasmania. I’m not sure how effective that protection is when there’s nobody watching 😉

      • davidmhoffer,
        Further, I’ve no idea how they could actually separate climate factors in the first place.
        – Neither do they, but that doesn’t stop them pretending …

      • “Over the last century we’ve seen major changes in farming practices ranging from specific strains grown (many of those developed for specific climates!), low till or zero till, no more stubble burning, herbicides, pesticides, even treatments to initiate ripening to control harvest time. How would you possibly separate out all these (and other factors) from changes of a few tenths of a degree over a century?”
        Production variability is measured against ‘Trendline Yield” The upward sloping trendline in all crop production encompasses the technology advances. A yield miss (up or down) is measured vs the trendline estimate of that year.
        I know some of the Ag professors at the U of M and they are quite reasonable and smart guys. I don’t see their names on this paper. I dont’ think they would sign off on the misleading message.
        Can we please put a chronological number on how many years it takes to move from weather to climate. To me, climate is 1,000 years. Weather is a lifetime (100 years). Big grey area between those two numbers, but certainly you can not measure climate by a wheat plant that grows for 90 days per year.

      • Mr. Git,

        “For me this was the “year of the cutworm”. I suspect this was due to a marked decline in the small bird population…”

        If that is truly the case then we have another reason why the eco-loons are pushing more wind turbines. More turbines means fewer birds means more bugs means less food and therefore fewer people. The wind turbines also have the “plus” of making irrigation pumping less reliable as well, following your point about water made at the top of this thread… again with the end result being fewer people (or more people living at Stone Age levels.)

      • …It was caused by Robert Mugabe, who gave the land back to it’s rightful owners. Catastrophe ensued, of course. Check out the number of tractors purchased by Zimbabwe during that time period. They went from being the breadbasket of Africa to just another steaming pile of poo in a few short years, thanks to social justice.

      • Eric.
        You forgot to put ‘rightful’ in quote marks. If you park a car on the street for 20 years and never touch it, there will come a point in time when you find you are not the ‘rightful’ owner you thought you were.
        R

      • Eric Sincere
        January 22, 2015 at 11:44 am
        … thanks to social justice.

        So you’re against social justice. Does that mean you support social injustice?
        People have a sense of fair play. When they feel that they are being cheated, it’s easy for a tyrant to step in and make things even more unfair. Just because someone uses the phrase “social justice” it doesn’t mean that they actually intend to create social justice.
        I remember UDI. How did that turn out?

  3. A warmer climate is more stable, with less seasonal variation. A cooler climate is prone to much wilder swings of weather, temperature, and precipitation. Which is better for agriculture?

  4. When the continent-spanning glaciers again advance, how will this affect ‘food security in a cooling world’?
    We don’t know why cyclic major glacial advances occur but we know with high probability it’s going to happen again. It’s just a matter of when……
    Attempting to present annual variations in regional crop yield data as witness marks for ‘climate variability’ is misrepresentation at best… and willful perversion at worst.

  5. Am I missing something. Didn’t we already know that precipitation and temperature affect crop yields. I think the first humans who found they could harvest their own food figured this out fairly rapidly.
    If the effort is to quantify a relationship between precipitation, temperature, and crop yields so they can then model future scenarios into climate models then they are getting paid to waste their time. The 33% figure and the term “climate variability” are more vague climate terms and ignores the most obvious; for farmers and everyone else on the planet all weather is local.

  6. Many farmers in the USA choose fertilizer additions and seed/plant spacings appropriate for above average rainfall conditions for their areas. Historically, this planting ‘strategy’ has produced very high yields when moisture is plentiful at regular intervals during the growing season. In drier years, the yield is reduced but still usually sufficient to cover the planting costs and provide a modest profit. Averaged over the years, their profits are higher than if they just planted for a ‘normal’ rainfall year all the time.

  7. Another waste of money to tell us what I could have said sitting in my armchair. Bad weather affects crops. You will notice bigger problems with bad weather where crops grow really well than places where they are bad to begin with!
    Can I have some cash now?

  8. Went and read the open access paper and the SI. Massive data massage to show the obvious, that weather affects crop yields some. Just like on my farm, every year.
    But on shakier grounds concerning how much. The statistical work did not distinquish irrigated from unirrigated land. It did not distinquish cultivars (wheat is not separated into winter and summer types, yet only one ‘typical’ wheat growing season was input from a separate reference). The ‘political units’ vary vastly in size. County level data for the US midwest is not the same as provincial level data from China. The only way they get the stats they do is by the massive data block (13500 units x 30 years, each tested separately for several equation best fits). And even then, some of results are p 0.05 or even p 0.1. Shakey stuff.

  9. It’s amazing how scientists can find the effects of climate change…when the temperature does not change

    • That’s because climate isn’t temperature no matter how the CAGWers huff and puff. From the OED:

      Climate: Condition (of a region or country) in relation to prevailing atmospheric phenomena, as temperature, dryness or humidity, wind, clearness or dullness of sky, etc., esp. as these affect human, animal, or vegetable life.

  10. I wonder how they could combine temperature and precipitation to a single number and call a change in that number a climate change. How many combinations of these two variables would give the same “climate or weather”?
    I really miss the climate science to tell how to combine all the parts in climate to a single significant number, so that you could tell if it got worse or better.

  11. But I thought they say that climate isn’t variable – it is only increasing in heat??
    They’re really just trying to confuse people with words like variability and change. Isn’t variability the same as change?
    They’re out to prove a point, and they will say/do anything to do that.

  12. Basically, just a grant-farming mechanism to get “climate change’ funds for their database of crop production statistics. As a number of people have pointed out, this is just confirmation that weather affects crop production. Add in the subtle morph from weather to climate change and sneakily switch into variation in yield (as opposed to total yield) and you can get a headline of “30% due to climate change”. Clever headline writing, but nothing else.

  13. depending on the crop, and phase of the growing season, crops are hurt by too much rain, too little rain, too hot, or too cold. Since climate change causes all of these, crop production will drop. QED.
    See how easy it is to argue their side?

  14. I’ve a problem:
    “The links between climate and yield variability differed among regions. Climate variability explained much of yield variability in some of the most productive regions, but far less in low-yielding regions. “This means that really productive areas contribute to food security by having a bumper crop when the weather is favorable but can be hit really hard when the weather is bad and contribute disproportionately to global food insecurity,” says Ray. “At the other end of the spectrum, low-yielding regions seem to be more resilient to bad-weather years but don’t see big gains when the weather is ideal.” Some regions, such as in parts of Asia and Africa, showed little correlation between climate variability and yield variability.”
    The point starts out talking about climate, then switches to weather. I thought that we’d been told, over and over again, that weather isn’t climate. Unless, of course, it needs to be to prove a point?

  15. The climate has been amazingly good for agriculture.
    http://thebreakthrough.org/index.php/programs/conservation-and-development/can-we-grow-more-food-on-less-land
    “That’s why I was surprised to find what appears to be good news lurking in global data (from the U.N. Food and Agriculture Organization, FAO 2014) while I was doing research for a chapter in an upcoming book (Agricultural Resilience: Perspectives from Ecology and Economics – coming from Cambridge University Press later this year).
    I found that, while the global food supply per person has increased over the last 15 years, we have simultaneously decreased the total amount of land we’re using to produce it”

  16. “•About 32 to 39 percent of year-to-year variability for the four crops could be explained by climate variability” it seems like they should be saying the weather of a given year is the issue not the climate, though they are going to get more money for studying it if they say climate and bad in the same paper.
    Joe Civis

  17. “The research team is now looking at historical records to see whether the variability attributable to climate has changed over time.”
    Shouldn’t they have done this work prior to quantifying how climate has effected crop yield?

  18. Jean-Louis of Agence France-Presse has a story that is spreading fast in the CAGW-infested MSM, and it is telling a different story!!!
    23 Jan: Sydney Morning Herald: Jean-Louis Santini/Wires: Climate change brings world closer to ‘doomsday’, scientists say
    Climate change and the danger of nuclear war pose an ever-growing threat to civilisation and are bringing the world closer to doomsday, a group of prominent scientists and Nobel laureates said Thursday.
    “It is now three minutes to midnight,” said Kennette Benedict, executive director of the Bulletin of the Atomic Scientists, as the group moved its symbolic “Doomsday Clock” two minutes forward…
    “Efforts at reducing global emissions of heat-trapping gases have so far been entirely insufficient,” said ***Richard Somerville, a member of the Science and Security Board, Bulletin of the Atomic Scientists, and a distinguished professor emeritus and research professor at Scripps Institution of Oceanography, University of California San Diego.
    “Unless much greater emissions reductions occur very soon, the countries of the world will have emitted enough carbon dioxide and other greenhouse gases by the end of this century to profoundly transform the Earth’s climate,” he said, noting that 2014 was the hottest on record and that the tipping point of ice loss in west Antarctica has been reached, meaning the melt is now unstoppable…
    http://www.smh.com.au/environment/climate-change/climate-change-brings-world-closer-to-doomsday-scientists-say-20150122-12wex9.html
    ***2011: WUWT: Bogus claims on Australian and Brazilian floods from ABC and Dr. Richard Sommerville
    http://wattsupwiththat.com/2011/01/14/bogus-claims-on-australia-and-brazilian-floods-from-abc-and-dr-richard-somerville/

    • seems like we’ve been minutes to doom since I was a kid = long time now (but we’ve had those other wars on poverty, drugs, communism . . . and now climate or warming or CO2 or tipping poles)

  19. I think the authors of the study are kerfluxing climate and weather. The climate has not changed nearly enough nor often enough to be blamed for anything. On the other hand farming technology, hybridization, irrigation, and other related factors change and improve frequently and not always for the better, and changes in technology can easily mask effects of weather. Moreover, farming has moved en mass to marginal areas where cheap energy, good will, and tax dollars permit it but where weather, soil, and labor-intensive technology discourages long term success. What comes to mind is Canadian wheat and trying to grow anything in arid Africa. I would bet that more food acreage is lost to biofuel policies than is lost to weather variability.
    Another factor is politics and meddling in agriculture. Here in our region we watched acres and acres of apple trees drop fruit and then the felling of the trees as orchardists gave up trying to make a living. I can easily see in my lifetime, and I’m old, when labor costs are so high that apples will have to be imported like cheap plastic products from Asia – exactly what happened to cane sugar and pineapples from Hawaii.

    • I disagree, I think they read “grant money” with excellent accuracy, comprehension and perspicacity.

    • if I remember correctly the Hawaiian sugar issue was due to Reagan’s policy trying to promote use of high fructose corn syrup to benefit the corn growers, by instituting/raising the tax on sugar. It is/was political meddling as you mentioned. As with most if not all government policies the secondary affects are rarely considered and if they are considered they are routinely discounted as being insignificant.
      Cheers!
      Joe

  20. In the Horn of Africa, Ethiopia etc, crop yields are nothing to do with climate change and everything to do with changes in farming practices since the 1980’s famine!

  21. Curiously the Chart shows ‘Climate Change’ as having no effect on production in Australia! Agricultural production in Australia has always had wide swings caused by variations in the weather. This omission throws the rest of the Chart into severe question and suggests that it has just been ‘made up’.

    • The open access paper and SI do show major swings for Australian wheat.
      And the paper didn’t try to cover PompousGit’s amazing potato yield. Man, good underlying growing conditions. More of northern Wisconsin is getting into fancy potatoes, converting from vegetables in ‘the sand hill country’ that produces lots of US frozen veggies. Comparative potato yields are pathetic, but then they are only the high priced fancies.
      We are mainly maize, soy, oats (alfalfa first year cover crop) and alfalfa on my SW Wisconsin biggish ( barely top 25% in the state) dairy farm. Sometimes some winter wheat depending on the fall harvest timing. Sell excess maize to ethanol distillers, get back distillers grain to reduce the alfalfa/ chopped green corn component of dairy feed. Allows a changed cropping rotation on the contours. About 1.8 to 2 million pounds of Class A milk/year the main product, lots of veal/steers since only females milk (and because of the US beef situation given semidrought elsewhere, we presently get $400/ head for a week old steer! Minting money, since used to be $25. So you know that won’t last—just weather and farmers), some beef the minor. Hamburger is what happens to dairy cows after a few freshenings when their milk production drops. And, PG, cowbarn manure makes great nitrogen/phosporus fertilizer. We produce lots for free…except for the expensive manure spreaders. Only supplement K. But apparently you don’t need any, and we could not afford to ship it to you anyway. Regards.

      • Based on some trials I had a hand in some 20+ years ago, we could do better than that. Artificials applied at about half the recommended rate plus the organic fertilisers I use (compost, aged animal manures and regular foliar applications of fish & seaweed emulsion) and, critically, sub-surface irrigation at a carefully controlled rate. A farmer I know managed 120 tonnes/Ha on his first go.
        What the armchair pundits don’t realise is it’s the yield at the bank that counts. Maximising yield per hectare is never going to be good for the bank balance. Maximising yield per man-hour makes more sense, but then it too fails to take into account many other important factors. But then you already know that as a farmer.
        Yes, FYM is invaluable stuff and happily Australian farmers are rediscovering it.
        Sounds like you are creaming it with the beef 🙂 Congrats.
        You’re correct we don’t need, or could afford to purchase your manure. Interesting you need K supplement. When I first purchased the farm, K was ca. 40 ppm so I applied some muriate of potash. Three years later it had reached 268 ppm, way higher than what I had applied. Organic matter had gone from 8% to 14 % and CEC from 8.86 to 20.14. Available P from 89 ppm to 463 ppm.

  22. reality check on the loss due to “climate variability” -36 million tonnes vs 2.3 BILLION tonnes
    http://www.unep.org/wed/2013/quickfacts/
    •The amount of food lost or wasted every year is equivalent to more than half of the world’s annual cereals crop (2.3 billion tonnes in 2009/2010).

    • Perhaps it would be more clear if I stated it as 36 million tonnes vs.HALF of 2.3 BILLION tonnes.

    • The problem is, when you dig into the UNEP and FAO country level data, it just is not true in any literal sense. Certainly not true for all the major big four staple grain producers like US, Canada, Brazil (soy), Argentina, Russia , Ukraine (wheat), China (rice, maize–and guess who is the number 1 producer of potatoes in the world? Some hints. Ain’t the US. Russia is #3, India is #2), Australia…
      Maybe its that ‘equivalent to’ thingy given an 1:4 caloric conversion to meat protein from maize and soya, so this is really a UNEP vegan plea…? Makes more sense that way. Good researching spot, but just shows more UN duplicity.

    • In my calculation above I just looked at the crops they specified, wheat, rice, corn and soybean. I still think the correct comparison is 36 million tonnes versus 2,400 million tonnes of those crops produced. Anyway, the proportion affected is not very big.

  23. From the University of Minnesota:
    When it comes to variations in crop yield, climate has a big say
    Discovery of the huge but varied role of climate change in food production provides valuable insights for preparing for future conditions
    Maybe they should just stick to cheese?
    michael

    • No, No, No.
      Wisconsin does cheese. Proof, Green Bay Packers cheesehead fans.
      Minnesota does hogs. Proof, Hormel (Spam) headquarters.
      Although Iowa is giving Minnesota a run for their money concerning ‘hog heaven’. Proof, new US senator Joni Ernst.
      With apologies to North Carolina concerning hogs but NOT cheese.

  24. @The Pompous Git January 22, 2015 at 11:29 am
    …I’ve said this many times here: “The single biggest factor in crop yield is water”. Specifically, insufficient water reduces yields. It’s why humans now sequester ~50% of rainfall…
    Really? Do you have a cite for that? Even counting all the dams in all the world, and all the aquifers as sequestered rather than natural, half of all our rainfall sounds rather a lot to me…

      • Comes from a slide presentation linked to by Roger Pielke Sr several years ago. Since the PPS wasn’t located on Pielke’s website, searching there requires me to remember the context. Aaargh!
        Why is the Internet so slow today? 12 Mb/s my arse!
        Sarah Postel has a paper saying 54%, but the execrable Ehrlich is a co-author. See: Human appropriation of renewable fresh water 1996. http://www.sciencemag.org/content/271/5250/785.short
        It would appear that 11-13 % is sequestered behind large dams (http://www.giss.nasa.gov/research/briefs/gornitz_06/)
        but that doesn’t include rainfall that is sequestered in small and medium sized dams, general agricultural produce, and forestry. We are also using fossil water (underground aquifers) faster than replacement. Obviously ~50% didn’t appear outrageous to Pielke Sr, and it doesn’t to me. But then I’m a farmer who sequesters his local rainfall.

      • I intended to write: “But then I’m a farmer who sequesters most of his local rainfall.” Most of it grows grass for cattle. Run-off only occurs during heavy rainfall, and wintertime when pasture has low water needs.

  25. The best I can do for water use estimates involves back of the envelope calculations from figures in the wiki, so nothing below is reliable. But my estimates are:
    Of total world annual water use, 70% goes to agriculture. This is given as approx. 2 x 10 to the 9 cubic meters. Which suggests that total world annual water use is approx. 3×10 to the 9 cu.m.
    Total world annual rainfall is 5×10 to the 14 cu.m. Assuming we sequester ALL the water we use, we sequester approx.1/500,000 of total rainfall.
    Unless someone who knows better can correct me?

    • DG, your surface water ag use numbers are roughly right. But you missed some very important things hidden in the UN water data background. For serious referenced details, see the water chapter of ebook Gaia’s Limits. Too convoluted (and ‘shocking’ concerning yet more UN deception) to explain in a brief post here. Regards.

  26. But does not the IPCC say that until 2060 at least — using their greatly highballed projections — there will be what they quaintly call “net beneft” for both man and beast?

  27. The biggest threats for food production from an historical perspective isn’t climate.
    1. Centralist experiments like the USSR under Stalin triggering the biggest famine of our modern history killing 20 million Russians
    2. Centralist mandates transforming 40% of the maize crops in Europe and the USA into bio ethanol.
    3. Lying Green Activists delivering fraudulent reports resulting in the ban of pesticides (dying of bees)
    4. Big money and political zealots blowing up the financial system using Government debt bonds to back derivatives trading.
    5. Sanctions and war
    Yes, political man and financial man teaming up with green zealots, the worst enemies of human kind.

  28. “The results of this study and our follow-up work can be used to improve food system stability around the world by identifying hot spots…

    I see what they did there.

  29. This was published so that ” …information planners and policy makers can use to target efforts to stabilize farmer income and food supply and so boost food security in a warming world.” Evidently to introduce the two words “warming world” that draw funding. They only looked at variations within fairly normal range. Actually things are much worse than that. During the Little Ice Age millions died because of crop failures due to climate change.

  30. Then there’s crop spoilage. Rye grown in cold wet times can play host to ergot, a nasty fungus. That spoilage can waste a big proportion of the crop. Ergotism is … unpleasant.

  31. LOL!! Wow…. So these brilliant researches found that when the weather is good, crop yields are good….. and… when the weather is bad, crop yields are bad….. Who knew?
    In the US, crop yields have increased a whopping 80% just since the 1980’s… Obviously a lot of this increase is due to advances in: farm machinery, high-yield seed development, fertilizers, irrigation, insecticides, herbicides, etc., but increased CO2’s fertilization has also contributed to the rapid increase in global crop yields:
    http://data.worldbank.org/indicator/AG.YLD.CREL.KG
    IPCC’s AR5 report also admits that global severe weather frequency and intensity have been flat for the past 50~100 years so what the heck are these researches trying to prove?:
    http://wattsupwiththat.com/2013/10/03/pielke-jr-agrees-extreme-weather-to-climate-connection-is-a-dead-issue/
    Why the heck is CAGW still taken seriously? Why is taxpayer money still being thrown down rabbit hole for these inane and worthless “research” papers that vainly try to contrive support for the disconfirmed CAGW hypothesis?
    Isn’t a good thing global temps have recovered 0.75C since the end of the Little Ice Age? Won’t this small amount of warming make winters milder, extend growing seasons, increase arable land area in the Northern latitudes, slightly increased precipitation, extended treelines, etc.?
    Where is the catastrophe?
    How long will this insanity continue?

    • Watch out for the claim of herbicides increasing yields. Usually it’s the reverse. Roundup Ready crops are resistant, not immune to glyphosate. The crop recovers and the weeds die. If you sow an RR crop into a weed-free paddock and use tillage for weed control, the yield is considerably higher.
      Here’s an experiment you can conduct at home if you have a spare patch of grass and clover lawn. Spray off a patch with glyphosate (Roundup/Zero) and inspect it every few days. At first it looks as though both clover and grass will die, but after a couple of weeks, while the grass is dead, the clover will be well on the road to recovery. Selective herbicides are designed to increase profits, both of the manufacturer of the herbicide and the farmer. Chemical ploughing is supposedly less expensive than mechanical ploughing. Very often it’s used to conserve organic matter and topsoil.

      • The Pompous Git– Obviously, since farmers use herbicides, they serve a purpose. If herbicides decreased profitability and/or crop yields, then farmers would stop using them…
        Many of my relatives are farmers and I worked many summers on my grandfather’s farm.
        Trust me, farmers know what they’re doing; at least the ones that still remain in business. Many farmers have gone out of business or have been bought out by large farm conglomerates, but that’s just how the market works.
        In the 1930’s, there were about 7 million farms in the US. Now there are only around 2 million farms and only about 2% of the US population actually work on them (used to be around 30+% in the1900’s).
        Farming is a very tough and competitive business. If you don’t get everything exactly right, you go bankrupt… I think I read somewhere that only 25% of family-owned farms make more than $50,000/yr in profit. A typical profit margin for a farm is just 9% (used to be closer to 30%)….

      • Perhaps you should read what I wrote, rather than what you wish I wrote:

        Selective herbicides are designed to increase profits…

        The rule of thumb I was taught was that selective herbicides decrease yields in cereal crops by 10–15%.

  32. That the climate has an impact on crops is not new: grapes were harvested farther North in Europe during the warm Roman period, and Greenland was green.
    That the climate has an impact on crop yield variability will remain unknown for a very long time, if at all possible.
    Why should a slow and steady change have an impact on short term variability? Is it important?
    No control experiment can be undertaken (crop with climate change compared to crops without climate change).
    And if other long term observations could serve to seek correlation with climate change, then all other parameters would need to be filtered out, such as short term weather variations (1 to 7 seasons involving many individual parameters), agronomic changes (plant varieties, fertilization, pest control, etc.).
    To get statistical significance would require an impossibly gigantic set-up, and centuries.
    Historic records will not provide such data. Models are worse.
    Useless study, and, most probably, totally wrong (there is a 99.99% confidence that it is totally wrong, the rest leaves room for partial correctness).
    If the people doing it were actually intelligent, they would dedicate their efforts and intelligences to more purposeful endeavours.

  33. The world warmed 0.12ºC per decade during 1951-2012, according to the IPCC (AR5 Summary for Policymakers, p. 5), which implies an overall warming of about 0.72ºC. What happened to global average wheat yields during that period?
    I haven’t found data for 1951-1960. However, average global wheat yields increased by 33% in the 1970s, 27% in the 1980s, 20% in the 1990s, 9% in the 2000s, and 10% during 2010-2014. Average yield was 149% higher in 2010-2014 than in the 1960s (my calculations based on USDA data: http://www.ers.usda.gov/datafiles/Wheat_Wheat_Data/Yearbook_Tables/World_Production_Supply_and_Disappearance/wheatyearbooktable03full.pdf).
    Similarly, average global output increased every decade and during the past five years. Average output was 157% higher in 2010-2014 than in 1960-1969, increasing 16% in the 1990s (allegedly the warmest decade of the millennium) and 12% in just the past five years.
    That is all the more remarkable considering that Russian grain production fell by nearly 40% in the 1990s after the collapse of the Soviet Union (http://dash.harvard.edu/bitstream/handle/1/9556127/Hamm_gsas.harvard_0084L_10406.pdf?sequence=1).
    If recent history is any guide, the ingenuity of farms will continue to trump climate change over the next several decades.

  34. I doubt, this type of research has any meaning yet all. Crop yields are highly variable under irrigated agriculture and under rainfed agriculture. How, any body could estimate a decrease in yield with climate change. What is climate change? Climate is represented by several meteorological parameters. Crop growth is affected by different parameters while development is affected by different parameters. The soil type plays important. Some of these I discussed in my two books available at http://www.scribd.com/Google books — Agromet/Agroclimatological methods: As applicable to dry-land agriculture in developing countries [1993] and “Green” Green Revolution: Agriculture in the perspective of climate change [2011]. Let me give an case: In late 70s, ICRISAT.Hyderabad tested a model developed at AM Texas, known as “SORGF”. They conducted experiments in India as well some other developing countries [collaborative experiments]. With this data the model was tested for its application to tropical countries. The correlation coefficient achieved with biomass and grain yield was very low. Then they tried by changing energy sub-model and yet no improvement. At the meeting, the Director General of ICRISAT Dr. Swindale [a former professor from Soils from Hawaii University] asked me to change the water balance sub-model with my model [ICSWAB — published in International Agricultural Meteorology Journal in 1983]. The modified results were presented at the next day meeting. The correlations improved significantly [around 0.3 to around 0.8]. Also, a series of papers appeared in the same journal on the energy efficiency terms. My comment on these articles were also published in 1994. That means,in tropical countries energy factor is not that much important as that in extra-tropical countries. In tropical countries moisture is the major limiting factor. Also, in India the wastage of food is as high as 40-50%. This I presented on All India Radio talk in 2010 and the Finance Minister said the same in his 2011 budget speech.
    In 2008, when with the mis-use of water in a dam, the Rabi paddy crop in the state of Andhra Pradesh in India has no water, then the Chief Minister of the state used innovative technique [bore wells in river Godavari] and resulted bumper yields. These are nothing to do climate or weather.
    Dr. S. Jeevananda Reddy

  35. # “climate change accounts for only 1/3 of crop yield variation”
    … and the other 2/3 is due to …
    … is due to …
    … is due to …
    WHUT

  36. “More than 60 percent of the yield variability can be explained by climate variability in regions that are important producers of major crops, including the Midwestern U.S., the North China Plains, western Europe and Japan.”
    All being regions that will get adversely effected by increased negative NAO/AO in the weaker part of this solar minimum from late 2015 to 2024. Also more frequent El Nino will increase drought in Australia, and with increased positive Indian Dipole events increasing drought in India/Indonesia. I doubt that Asia will be that resilient, especially India. For example the Agra famine of 1837/38, that kind of weather is just round the corner through 2016/17.

  37. I would say the climate change, that has been in part generated by humans, had taken already a big toll. And it also costed alot of money, spent with intention or circumstancially…..

Comments are closed.