New evidence that global warming will hurt US wheat production

May 12, 2015 by Bob Yirka, Phys.org report

Credit: Wikipedia
(Phys.org)—A trio of researchers, one each from Mississippi State University, Kansas State University and the University of Arkansas has found evidence that suggests global warming will cause a reduction in U.S. wheat production in the years ahead. In their study published in Proceedings of the National Academy of Sciences, Jesse Tack, Andrew Barkley and Lawton Lanier Nalley describe how they studied winter wheat production for an area in Kansas and compared it against weather data and what they found by doing so.

As the planet continues on its apparently inevitable march to a warmer future, scientists the world over are scrambling to understand what impact it will have—from rising ocean levels to crop production. In this latest effort, the researchers sought to find out what might happen to wheat yields in the United States as temperatures rise. To say that wheat is an important crop is an understatement, it accounts for 20 percent of total daily calories consumed by humans across the globe, and represents a far higher ratio for many people in third world countries. Scientists have been working hard for many years to increase the amount of that a farmer can get from a given field—currently such yields are still seeing increases of approximately 1 percent each year, which is remarkable. But that may change soon, this newest research suggests.

For over thirty years, winter wheat trials have been taking place in Kansas, home to one of the largest producers of wheat—$2.8 billion worth in 2013 alone. That trial has yielded a lot of data, some of which the research team found indicated that modern strains are vulnerable to both extremely high and low temperatures. The low temperatures are not much of a concern in this study of course, but the high temperatures appeared to cause significant yield reductions—they even found a cutoff point—34 degrees Celsius. Overall they found a 15 percent reduction in yields when temperatures rose on average just 2 degrees Celsius and a 40 percent decline when went up just 4 degrees. Sadly, they also found that more modern plants were more vulnerable than older strains.

What this means, the researchers suggest, is that places that currently grow wheat are likely to suffer as progresses. Currently, it is not clear if land lying north, where it will presumably be colder, will be able to support the level of predicted yield needs for the future.

Explore further: Study finds climate change may dramatically reduce wheat production

More information: Effect of warming temperatures on US wheat yields, Jesse Tack, DOI: 10.1073/pnas.1415181112

Abstract
Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985–2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September−May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields.

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23 comments

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Shootist
2.6 / 5 (14) May 12, 2015
And Canada and Russia will grow more wheat.

Climate Change. Shazam! Is there nothing it cannot do?
gkam
2.3 / 5 (15) May 12, 2015
Simpletonian logic will fail you.
antigoracle
2.4 / 5 (13) May 12, 2015
What an absolute joke.
The US has been cooling since the 1930s.
gkam
3.3 / 5 (19) May 12, 2015
Mister Political Prejudice, anti, shows us how silly one can get by sticking to a politically-derived rationale in science. I suggest he look up the ten hottest years ij history and get back to us.

We're waiting, anti, . . . .
jeffensley
3.2 / 5 (5) May 12, 2015
Perhaps this spells a return to older, hopefully non-GMO strains of wheat.
denglish
2.2 / 5 (13) May 12, 2015
Give us your money, or the earth gets it.

phys.org won't be the first rag to lose credibility fostering the AGW myth.
ryggesogn2
2.6 / 5 (10) May 12, 2015
What does it matter?
The 'in' thing is to go gluten free.
gkam
2.3 / 5 (12) May 12, 2015
"Perhaps this spells a return to older, hopefully non-GMO strains of wheat. "
--------------------------------------------

Interesting comment, Jeff. But I think it will make some profit-motivated lab to produce some GMO type to deal with the changing conditions. I do not know if that is good or bad, but our tools have outstripped our wisdom.
jeffensley
3 / 5 (3) May 12, 2015
Interesting comment, Jeff. But I think it will make some profit-motivated lab to produce some GMO type to deal with the changing conditions. I do not know if that is good or bad, but our tools have outstripped our wisdom.


"Sadly, they also found that more modern plants were more vulnerable than older strains."

That's what makes me think we'll see a comeback of older varieties.

antigoracle
2.3 / 5 (9) May 12, 2015
Bongstar420
3 / 5 (3) May 12, 2015
Interesting comment, Jeff. But I think it will make some profit-motivated lab to produce some GMO type to deal with the changing conditions. I do not know if that is good or bad, but our tools have outstripped our wisdom.


"Sadly, they also found that more modern plants were more vulnerable than older strains."

That's what makes me think we'll see a comeback of older varieties.



I always thought you plant what would likely do well. Obviously, a shift in cultivars and types is in order.
antialias_physorg
5 / 5 (10) May 12, 2015
I think a lot of people don't get what global warming means. It does not mean "everywhere will just get the weather they get now - just a degree or two warmer". If that were so, that would be bad enough (sea levels rising and whatnot).

But what it really means is more energy content in the atmosphere and in the oceans. Which means more weather EXTREMES. And even the most simple simpleton can understand that it doesn't take constant drought or a constant storm to ruin a harvest but just a very sudden/limited one.

It doesn't matter that your plants grow 1% better over a season when the likelyhood is 20% greater that 100% get destroyed. You still come out on the (very much) losing end on average.
jeffensley
1 / 5 (7) May 12, 2015
But what it really means is more energy content in the atmosphere and in the oceans. Which means more weather EXTREMES. And even the most simple simpleton can understand that it doesn't take constant drought or a constant storm to ruin a harvest but just a very sudden/limited one.


Are these statements based in fact or fear? I think you see what you want to see. Evidence currently indicates no such trend.

http://www1.ncdc....-EF5.png
https://wattsupwi..._year_19
http://onlinelibr...abstract
http://www.ic.ucs...ycle.pdf
dbsi
2 / 5 (3) May 12, 2015
...global warming will hurt US wheat production...
This might be that argument which makes a Global Warming skeptic, sceptic to Tea Party sponsoring. But then, who knows, he might discard his conservative profit caring and cheer instead his perverted conservatism.
dbsi
1.8 / 5 (4) May 12, 2015
...global warming will hurt US wheat production...

This might be that argument which makes a Global Warming skeptic skeptic to Tea Party sponsoring. But then, who knows, he might discard his conservative profit caring and cheer instead his perverted conservatism.
jeffensley
1 / 5 (6) May 12, 2015
jeffensley - did you read your own links? Here is a quote from the last one -
the weight of evidence is consistent with an ongoing and future intensification of the hydrologic cycle


Yeah which means an increase in volume of water evaporating, condensing, and falling down again as snow or rain. If you want to interpret that as support of increased "extreme" weather please have at it. I'll take the decrease in tornadoes, droughts, and hurricanes making landfall as indication that weather has NOT gotten more extreme.
EnricM
3 / 5 (4) May 13, 2015
but that term can include increased precipitation, flooding, and droughts. Again - look at table 1.


Actually, there is no need for global warming to see an increase in these: Desertification alone, without any other factor is doing a very good job doing that. If in doubt ask the Spaniards or South French. The Iberian Peninsula is plagued by cycles of droughts and heavy rains and while the alternation of dry / wet periods should be normal in the Mediterranean, their intensity and effects are not as in the past the tree and vegetation cover held the soil in place and attracted precipitation.

Trying to deny this sort of things just for the sake of fancy climate denialism is just utterly stupid. And please note again, that there is no need of Global Warming for this to happen as it is unrelated.

Ironwood
1.5 / 5 (8) May 13, 2015
Oh dear, another story about harm from climate change at phys.org. I also see four more pessimistic stories down below. If you only got your climate news here you wouldn't realize that current scientific studies show that the next 2 degrees Celsius of warming will be a net benefit to mankind. Current models predict we will be shivering in these less than ideal temperatures until around 2080.

antialias_physorg
4.7 / 5 (6) May 13, 2015
That's what makes me think we'll see a comeback of older varieties.

Well, that leaves two ways forward:
Plant the current crop types and risk the occasinal crop failure
or
Plant the old types and reap less per harvest

in both cases average yield goes down.

But I think it will make some profit-motivated lab to produce some GMO type to deal with the changing conditions.

It's an issue of energy. The amount of energy a plant can use is limited. GMOs do not create magically bigger/stronger/higher yield plants. GMOs simply shift the energy balance one way or another (e.g. increased resistance against some pest or bigger fruit). But that shift is always at a cost in all the other areas. There is no "free lunch" here.
jeffensley
1 / 5 (6) May 13, 2015
Again, people see what they want to see. Those most fearful of AGW will find a "negative" influence wherever they can and focus solely on that instead of actually looking at the hole picture. You pull one quote, I'll pull another.

"Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century."

So The Med is drier? Africa is greener. When will you all be willing to back off the catastrophe narrative?
ryggesogn2
1.1 / 5 (7) May 13, 2015
The amount of energy a plant can use is limited.

Limited by what?
But that shift is always at a cost in all the other areas.

What other areas?
gkam
3.4 / 5 (10) May 13, 2015
I can't believe Ryggy asked those questions. Does he not understand the limits of photosynthesis?
EnricM
5 / 5 (7) May 13, 2015
If you only got your climate news here you wouldn't realize that current scientific studies show that the next 2 degrees Celsius of warming will be a net benefit to mankind. Current models predict we will be shivering in these less than ideal temperatures until around 2080.


Sorry? You two last phrases look contradictory among themselves, unless I misunderstood the meaning of " shivering".

And where exactly are these fabulous studies about these benefits ? i

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