From AARHUS UNIVERSITY and the department of shredded wheat, comes this story. Maybe they should get out more.
Climate model predictions are telling a consistent story
Three independent methods of modelling climate change impact on yield display the same bleak tendency: When global temperature increases, wheat yield will decline. This is demonstrated in a study carried out by an international group scientists, including Professor Joergen E. Olesen and Postdoc Mohamed Jabloun from the Department of Agroecology at Aarhus University.
The good news is that the comparison of the three very different climate models allowed the scientists to be even more precise in their projections and enabled them to put more accurate figures on the relation between global warming and declining yields. The models unanimously demonstrate that for each 1°C that the global temperature increases, the global wheat production is projected to decline by an average of 5.7 percent.
Evidence-based action is necessary
The world population continues to grow and the standard of living continues improving. These two factors result in an increasing demand for food production. However, due to global warming we run the risk that food production decreases. Wheat is one of the world’s most important food crops and we face an important problem if yields fall concurrently with an increasing demand.
– When talking about global food security it is important to understand how climate change will impact crop production at a global level in order for us to develop fact-based mitigation and adaptation strategies, says Joergen E. Olesen.
Three ways to predict the future
The scientists compared three very different crop model types: grid-based, point-based and regression-based. The two first were simulation models while the third was based on statistical data analyses. Each type included a series of different models and thus included actual implementation of the model types.
A simulation model creates a model of reality based on the existing knowledge of reality. The model makes it possible to predict what will happen if some of the conditions/parameters are changed. Examples of input include facts on how crop growth periods and productivity react to temperature, precipitation and CO2 levels, and how evapotranspiration depends on temperature and atmospheric CO2 concentration. In such models you can tweak the temperature and find an answer to the question “What will happen if the global temperature increases by 5°C?”
Regression models use a statistical process for estimating the relationship between data. For instance, observed crop yield is statistically related to temperature and precipitation during the growing season. This estimated relationship can then be used to predict crop yield when temperature increases.
Grids, points and numbers
The grid-based model used by the scientists was based on the division of the world into geographical grid cells according to longitudes and latitudes. Together with climate and crop system data this division was used to estimate yields and production across the world in present production areas.
The point-based model applied data from 30 different locations (points) representing two thirds of the global wheat production. Results from these 30 locations were up-scaled to cover geographical areas with similar conditions.
The regression-based model was based on global and country-level data. This type allows for indirect effects such the impact of climate variation on crop pests and diseases, or crop adaptation to climate change.
Warmer regions suffer the most
Depending on the model in question, the expected wheat yield will decline between 4.1 and 6.4 percent with each 1°C global temperature increase. Warmer regions are most likely to experience the greatest decline in wheat yield.
This projected impact was similar for major wheat-producing countries such as China, India, USA and France but less so for Russia due to the generally cooler conditions of Russia’s wheat-producing areas.
– By combining several models we were able to improve the confidence of the estimates in relation to climate change impact on global food security, says Professor Joergen E. Olesen.
Read the scientific article “Similar estimates of temperature impacts on global wheat yield by three independent models” in Nature Climate Change here.
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The models unanimously demonstrate that for each 1°C that the global temperature increases, the global wheat production is projected to decline by an average of 5.7 percent.
Perhaps these guys should look at some “evidence based action”, such as crop yields in the “hottest year ever”.
Meanwhile, there’s so much wheat, that prices have been dropping sharply:
The long term trend seems to favor warmer temperatures and more CO2. But what do I know, I’ve only got some graphs of actual data, while these guys have a unanimous consensus of three computer models.
Historical Wheat yields From the USDA:
Year Yield
Bushels / acre
1950 16.5
1960 26.1
1970 31
1980 33.5
1990 39.5
2000 42
2010 46.1
Data extracted from
http://usda.mannlib.cornell.edu/usda/current/htrcp/htrcp-04-14-2016.pdf
So while temperatures and Co2 levels have been rising, the yields have also been rising.
Of course, CO2 is plant food !
This is the Technology contribution.
At what costs?
Harm it created to environment!!!
If we account all these, then the best yield is 1950 yield only.
Dr. S. Jeevananda Reddy
For the global temperature to rise by 5º something globally incredible has to happen. Something so incredible that humans haven’t the capacity to cause it or prevent it. If something that incredible happens wheat will be the least of our worries. The premise of this study requires a world that is inconsistent with life as we know it and there would be so many challenges to focus on that picking out wheat yield from the full scope of things that would change is silly and borders on fear mongering.
…When global temperature increases, wheat yield will decline. …
Probably not true, but it doesn’t matter, at least for the United States, because:
http://oi63.tinypic.com/156fl8y.jpg
Maximum summer temperatures have been declining for 80 years. For most states east of the Rockies the decline extends back to the 19th century.
http://oi68.tinypic.com/5pgzmf.jpg
The increase is in the minimum temperatures. The climate is getting milder. When our friends on the left tell us that extreme weather will be the new norm, they will have to talk about extreme mildness (-:
It looks to me that the maximum Summer temperatures have been increasing since about 1965. As much as I’d like to believe your claim, cherry picking end-points opens you to criticism from alarmists AND those who are objective.
If all the data are shown, it is not cherry picking. Multiple analyses can be performed, for longer and shorter periods, as the analyst may desire. A curiosity would be to see if US wheat yields vary in parallel with the chart such as it is.
The data for each state was downloaded from NOAA’s Climate At A Glance and analysed to see how far back in time you could go and still find a negative trend for the Maximum temperature. Try it yourself, go to Climate at a glance and pick any one of those states in the Mississippi or Ohio River valley and select the Max Temp, 4 months ending in September and display trend. Nearly all of them trend negative since 1895. There isn’t any cherry picking here.
Clyde, did you not notice that it goes UP, then DOWN, then UP…? What comes next, UP or DOWN ?
Read Bob Tisdale’s book “Who Turned Down the Heat?”. He has examples of what the minimums (and extremes) have done. I see that in a number of places in Environment Canada Data also.
I have a little different take, the extremes are not as extreme (UHI, GW, Clouds – who knows?):
https://www.dropbox.com/s/73bzb5btpja32ms/MedicineHatExtremes.tiff?dl=0
Just one example of many but 125 years of EC data on this location.
Well, of course the models are consistent, they all contain the same gross exaggeration CO2’s net forcing effect. Water vapor is the Elephant and the remaining GHGs are ants trying to steer it.
If you ate today, thank a farmer.
If cried yourself to sleep because you think that the world is going to end because of climate change, thank a computer modeller, a well-funded greenscare campaign and politicians who think you are as stupid as you appear to be.
A year of summer would be highly preferable to a year without summer from my view. Heres hoping that history doesn’t repeat itself soon.
Let’s see; models based on flawed models, or reality. Which to choose? Life is full of difficult decisions.
“When global temperature increases, wheat yield will decline. ”
Cool, so obviously models show that global cooling increases wheat yield right?
“Arse University”
’nuff said.
I am not sure if scientists are not taught the meaning of words, but the better word choice would be as follows:
“The models unanimously PREDICT that for each 1°C that the global temperature increases, the global wheat production is projected to decline by an average of 5.7 percent.”
It would be even better yet if the scientists got the science right!
Going by the logic we should get greater yields the colder it gets !
A significant weakness in the statistical analysis (and probably the other models as well) by the authors is in using average temperatures. A single-killing frost arriving prematurely can decrease the yield, yet not show on the temperature average. The theory of AGW predicts that most of the warming should be occurring at night and in the Winter. I demonstrate that in my article: http://wattsupwiththat.com/2015/08/11/an-analysis-of-best-data-for-the-question-is-earth-warming-or-cooling/ A slight increase in night-time temperatures will be benign, if not helpful, and crops (except Winter wheat) don’t grow in Winter. So, the mastication of the data by the authors simply confirms the old admonition — Garbage In, Garbage Out.
Practical farmers obviously know the extremes are bad, drought, early frost, hail, etc.
Here is a plot of extreme drought in the US.
https://www.epa.gov/climate-indicators/climate-change-indicators-high-and-low-temperatures
The 1930s were by far the worst decade for extreme drought.
“The 1930s were by far the worst decade for extreme drought.”
And the 1930’s were by far the hottest decade from that time to today.
It’s ridiculous for the climate alarmists to claim the 21st century was as hot or as dry as the 1930’s.
I live in an ag area. The grain elevators are full. The farmer’s bins are full. They are piling the grain on the ground. They are filling these giant white Ag-Flex bags to store even more. This is true for corn, wheat, millet, sorghums, and oats. I heard today that there is a 4 year supply of wheat in the world.
Time to brew beer, anyone?
Hefeweizen!
That darn climate change is producing lots of unforeseeable results like this-
http://www.msn.com/en-au/news/world/global-warming-alters-arctic-food-chain-scientists-say-with-unforeseeable-results/ar-AAkEiUQ?li=AA5249&ocid=spartandhp
The Arctic is greening along with the rest of the planet. Greenies hate that.
I guess every unforseeable Arctic greening has its silver lining for these people. Ever more grants to study the looming whale/seal/polar bear obesity problem.
On the bright side, the “work” was done at a Danish university so probably I didn’t pay for any of it.
Sorry..That darn foreseeable climate change….
“Evidence-based action is necessary”
True but where is the evidence again? Oh your computer models? Forgive me but I though those were theoretical simulations. Dang!
Cheers
Roger
http://www.rogerfromnewzealand.wordpress.com
Why won’t people just farm in higher latitudes? Why won’t people change from wheat to corn or some other warm weather crop?
Agricultural field corn needs more water. Most crops are limited by growing season and water.
The Church of CACA claims, when it suits its adherents, that a warmer world will be and must be a wetter world, contrary to the evidence.
They can’t gin up Catastrophic Anthropogenic Climate Alarmism without the positive feedback effect of more water vapor in the air, hence presumably more rain.
Do they put the correct amount of dust in their models?
To reduce, yet more ,uncertainties!!! Clouds! Dust!
“The modeling showed that if dust had even relatively small impacts on sea surface temperatures, this could have pronounced impacts on precipitation and winds both in the north Atlantic and over North Africa,” McGee says. Noting that the next key step is to reduce uncertainties in the modeling of dust’s climate impacts, he adds: “We’re not saying, the expansion of monsoon rains into the Sahara was caused solely by dust impacts. We’re saying we need to figure out how big those dust impacts are, to understand both past and future climates.”
Read more at: http://phys.org/news/2016-11-scientists-huge-reduction-african-plume.html#jCp
“We’re not saying, the expansion of monsoon rains into the Sahara was caused solely by dust impacts. We’re saying we need to figure out how big those dust impacts are, to understand both past and future climates.”
Someone has to break it gently to these guys that the science is settled.
The models unanimously demonstrate that for each 1°C that the global temperature increases, the global wheat production is projected to decline by an average of 5.7 percent
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So why has that not happened over the past 150 years, while temperatures have gone up 1C?
Oh yes, our models cannot predict the past, but they for sure can predict the future.
Please don’t confuse polemicists with facts. If the facts disagree with the models, the models are right. Because otherwise, no money.
Global wheat production and yield have increased so spectacularly in the past 150 years in part because of warmer weather. Even limiting it just to areas already producing wheat then.
Chimp, you were almost right.
It should read ” if the facts contradict the models, then the facts must be disposed of”
Seems to be the way of the Global Warmist Religion.
I stand corrected.
Post-modern science, in which inconvenient truths must be disposed of.
http://timesofindia.indiatimes.com/india/Rabi-marketing-Season-foodgrain-production/articleshow/35437468.cms
Punjab, in India, is not doing too bad, considering it never really gets cold…
https://www.yr.no/place/India/Punjab/Jalandhar/statistics.html
So because all the other models have been BANG ON, we need to give credence to this?
Stealing money I say, stealing money…
Food production and development never remains static. It improves. Don’t think they put that in their fractured models.
Where does the best wheat in the world grow? What is the climate like there?
Gareth–the best wheat for what? Hard wheat makes good pasta and bread, but lousy cake, which requires soft wheat. I think the growing requirements are different between the two types, too.
Not all wheat is created equal.
There are three basic types, to wit, hard, soft and durum. Do you want bread or pastry? Cakes or ale?
But the best wheat of all types is grown in the USA. We export wheat for spaghetti to Italy, because ours is better. We export wheat to Asia for noodles, because ours is better. Unfortunately for US growers, the strong dollar prices our varieties out of international markets.
The best wheat of all types is grown on “Chernozem” (see wikipedia), a byproduct of “extreme” climate (quite hot in summer, pretty cold in winter –killing pest and preventing quick rot, so roots turn into humus and fertilize following year crop). Found in USA, true, but also Canada, Ukraine, Russia, etc.
I don’t believe it for a moment. Crop yields have continued to grow as the planet got warmer and CO2 higher. However should these scientists be right, maybe we should stop using 40% of the American grain crops to make biofuels to run our cars on.