Harvests in the U.S. to suffer from climate change, according to study

January 19, 2017
Credit: SC Department of Agriculture

Some of the most important crops risk substantial damage from rising temperatures. To better assess how climate change caused by human greenhouse gas emissions will likely impact wheat, maize and soybean, an international team of scientists conducted an unprecedentedly comprehensive set of computer simulations of U.S. crop yields. The simulations reproduced a strong reduction in past crop yields induced by high temperatures, thereby confirming that they capture one main mechanism for future projections. Importantly, the scientists find that increased irrigation can reduce the negative effects of global warming on crops—but this is possible only in regions where sufficient water is available. Eventually, limiting global warming is needed to keep crop losses in check.

"We know from observations that high temperatures can harm crops, but now we have a much better understanding of the processes," says Bernhard Schauberger from the Potsdam Institute for Climate Impact Research, lead author of the study. "The computer simulations that we do are based on robust knowledge from physics, chemistry, biology; on a lot of data and elaborate algorithms. But they cannot represent the entire complexity of the crop system; thus, we call them models. In our study, they have passed a critical test." The scientists compare the model results to data from actual observations. Thusy, they can determine which critical factors to include in their calculations, including temperature, CO2, irrigation and fertilization.

Without efficient emission reductions, yield losses of 20 percent for wheat are possible by 2100

For every single day above 30°C, maize and soybean plants can lose about 5 percent of their harvest. The simulations have shown that the models capture the effects of small heat increases beyond this threshold, which result in abrupt and substantial yield losses. Such temperatures will be more frequent under unabated climate change and can severely harm agricultural productivity. Harvest losses from elevated temperatures of 20 percent for wheat, 40 percent for soybean and almost 50 percent for maize, relative to non-elevated temperatures, can be expected at the end of our century without efficient emission reductions. These losses do not even consider extremely high temperatures above 36°C, which are expected to lower yields further.

The effects go far beyond the U.S., one of the largest crop exporters; world market crop prices might increase, which is an issue for food security in poor countries.

Irrigation could be a means for adaptation—but only in regions where there's sufficient water

"The losses were substantially reduced when we increased the irrigation of fields in the simulation, so water stress resulting from temperature increase seems to be a bigger factor than the heat itself," says co-author Joshua Elliott from the University of Chicago. When water supply from the soil to the plant decreases, the small openings in the leaves gradually close to prevent water loss. This precludes the diffusion of CO2 into the cells, which is an essential building material for the plants. Additionally, crops respond to water stress by increasing root growth at the expense of above-ground biomass and, eventually, yields. "Irrigation therefore could be an important means of adaptation to dampen the most severe effects of warming," says Elliott. "However, this is limited by the lack of water resources in some regions."

Burning fossil fuels elevates the amount of CO2 in the air. This usually increases the water use efficiency of plants since they lose less for each unit of CO2 taken up from the air. However, this cannot be confirmed as a safeguard of yields under high temperatures, the scientists argue. The additional CO2 fertilization in the simulations does not alleviate the drop in yields associated with above about 30°C.

The comparison of different simulations and their impacts is at the heart of the ISIMIP project (Inter-Sectoral Impacts Modelling Intercomparison Project) comprising about 100 modelling groups worldwide. The simulations are generated in cooperation with AgMIP, the international Agricultural Model Intercomparison and Improvement Project.

Explore further: Dust Bowl would devastate today's crops, study finds

More information: Bernhard Schauberger, Sotirios Archontoulis, Almut Arneth, Juraj Balkovic, Philippe Ciais, Delphine Deryng, Joshua Elliott, Christian Folberth, Nikolay Khabarov, Christoph Müller, Thomas A. M. Pugh, Susanne Rolinski, Sibyll Schaphoff, Erwin Schmid, Xuhui Wang, Wolfram Schlenker, Katja Frieler (2017): Consistent negative response of US crops to high temperatures in observations and crop models. Nature Communications, DOI: 10.1038/NCOMMS13931

Related Stories

Dust Bowl would devastate today's crops, study finds

December 20, 2016

A drought on the scale of the legendary Dust Bowl crisis of the 1930s would have similarly destructive effects on U.S. agriculture today, despite technological and agricultural advances, a new study finds. Additionally, warming ...

Could global warming's top culprit help crops?

April 18, 2016

Many scientists fear that global warming will hit staple food crops hard, with heat stress, extreme weather events and water shortages. On the other hand, higher levels of carbon dioxide—the main cause of ongoing warming—is ...

Climate model predictions are telling a consistent story

November 23, 2016

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 ...

Soybean plants with fewer leaves yield more

November 18, 2016

Using computer model simulations, scientists have predicted that modern soybean crops produce more leaves than they need to the detriment of yield—a problem made worse by rising atmospheric carbon dioxide. They tested their ...

Recommended for you

New Amazon threat? Deforestation from mining

October 18, 2017

Sprawling mining operations in Brazil are destroying much more of the iconic Amazon forest than previously thought, says the first comprehensive study of mining deforestation in the world's largest tropical rainforest.

Scientists determine source of world's largest mud eruption

October 17, 2017

On May 29, 2006, mud started erupting from several sites on the Indonesian island of Java. Boiling mud, water, rocks and gas poured from newly-created vents in the ground, burying entire towns and compelling many Indonesians ...

21 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Benni
1.7 / 5 (12) Jan 19, 2017
The sky is still falling, only question remaining is when it hits ground level & what that will sound like, then we can all take a deep breath as the apocalyptic Church of the Holy Hockey Stick disbands.
Bart_A
2 / 5 (13) Jan 19, 2017
Well, nothing has been hit yet.

http://www.wri.or...ds_0.jpg

Actually it is going the other way. Yields from crops keep increasing every year.

antialias_physorg
4.7 / 5 (15) Jan 19, 2017
Well, nothing has been hit yet.

Tell that to the olive plantations in Spain and Greece. Notice how you're already substantially more for olive oil?
Yes: you will pay. And increasingly more so the less you invest in prevention. And very quickly the extra money you spend this way will becomr more than the couple of tax dollars you would spend the other way. But I guess some people just really get off on having to pay through the nose.

An ounce of prevention....
gkam
3.2 / 5 (9) Jan 19, 2017
Nasty little Denier voices will just disappear when it finally dawns on them what they did to everyone else.

They will not hang around for their comeuppance.
Shootist
1 / 5 (8) Jan 19, 2017
climate doesn't change on a scale quick enough to note anything other than Vikings cultivated wheat in Greenland for several hundred years, around 1000 years ago (you know?) before it became too cold to cultivate wheat. It's still too cold.
TheGhostofOtto1923
2.3 / 5 (3) Jan 19, 2017
"Harvests in the U.S. to suffer from climate change'

-The good news; harvests in canada and siberia to benefit from climate change. And valuable US farmland can be put to better use building malls and housing tracts for displaced tropicals.

Yay.
humy
5 / 5 (8) Jan 19, 2017
"Harvests in the U.S. to suffer from climate change'

-The good news; harvests in canada and siberia to benefit from climate change.

This may be true locally in some places because, with all else being equal, greater CO2 increases photosynthesis and thus crop yields. Unfortunately all else isn't equal and for most of the world the benefits of greater CO2 will be more than offset by far by the harmful effects and overall crop yield world wide may drop because of all the damage done by the greater frequency of severe weather events.
antialias_physorg
5 / 5 (11) Jan 19, 2017
climate doesn't change on a scale quick enough to note anything

Have you been living under a rock? Have you even gone outside in the past few decades?
Mark Thomas
5 / 5 (12) Jan 19, 2017
Other than a couple seasonably cold weeks, we are skipping winter again here in the mid-Atlantic U.S. It has been all rain, no snow, in January. Completely abnormal.

Always remember it was the Republicans that worked so hard for decades to do nothing about this so they could keep taking money from the fossil fuel industry. Denier and EPA pick Scott Pruitt, from the State of Oklahoma, a wholly owned subsidiary of Exxon, etc., took a reported $700K from big oil in 2014 alone. I wonder how much he got that was not reported?

http://bigstory.a...55cc3ea9
antigoracle
1 / 5 (9) Jan 19, 2017
Always remember it was the Republicans that worked so hard for decades to do nothing about this so they could keep taking money from the fossil fuel industry.

Uh huh, and where did they get all this money?
Tell us, when did you stop paying them to burn their fuel or did they hold a gun to your head?
Mark Thomas
5 / 5 (7) Jan 20, 2017
"where did they get all this money?"

If you had trillions of dollars in oil deposits, refineries, pipelines, gas stations and other fossil fuel investments wouldn't you pay to protect your business to keep selling? Exxon alone often makes billions of dollars per month in profit. Buying the loyalty of elected politicians is simply a cost of doing business. Republicans get the lion's share of the $, but this is not about ideology, it is about profit. The fossil fuel industry will support anyone who will use their power for them and oppose anyone who threatens their interests. It is really that simple. Follow the money.

antigoracle
1 / 5 (7) Jan 20, 2017
It is really that simple. Follow the money.

LOL.
It's actually much simpler than your simple mind is willing to fathom.
Yes, follow the money, right back to the pockets of the ignorant hypocrites like you. I'm still waiting for you to tell us when did you stop paying for fossil fuel?
howhot3
5 / 5 (7) Jan 20, 2017
LOL... Al Gore's 'An Inconvenient Sequel' Premieres to Standing Ovation at Sundance. It seems that people like what Al Gore has got to say. Maybe you will watch it. You might learn something. So maybe you will try to stop using fossil fuels? If you do it @anti, I'll do it.
antigoracle
1 / 5 (5) Jan 21, 2017
LOL... Al Gore's 'An Inconvenient Sequel' Premieres to Standing Ovation at Sundance. It seems that people like what Al Gore has got to say. Maybe you will watch it. You might learn something. So maybe you will try to stop using fossil fuels? If you do it @anti, I'll do it.

LOL.
Oh lookee what his man crush, Al, pooped out and how unsurprising, he's still dumber than a bag of hammers.

https://www.googl...ypocrisy
gkam
2.3 / 5 (6) Jan 21, 2017
Why is it the same folk who got fooled, suckered, taken, by those two draft-dodgers in the White House screaming "WMD!" from their bunkers and Undisclosed Locations are the same folk who voted for Trump?

After Putin saw how easy it is to fool our goobers, he did it, too. And they fell for it!

Now, they have to live with it.
TheGhostofOtto1923
1 / 5 (2) Jan 23, 2017
climate doesn't change on a scale quick enough to note anything


Have you been living under a rock? Have you even gone outside in the past few decades?
I am surprised that a comment as inane as this could get nine 5/5s. 'Going outside' on random days over a given period of time cant tell you anything about climate trends.

The unreliability of anecdotal evidence is why people began to methodocally record data in the first place.

Brainless uprating does however tell us a lot about the goats and sheep who are willing to do it.
Mark Thomas
5 / 5 (6) Jan 23, 2017
"The unreliability of anecdotal evidence is why people began to methodically record data in the first place."

That is true, but it doesn't mean you should ignore anecdotal evidence, especially when it becomes extreme. For example, we used to have something called "winter" here in the mid-Atlantic states in the U.S. During this "winter" most if not all precipitation in January fell in a solid form known as "snow." As incredible as it now seems, I swear to you I am not making this up. All this January, as well as all last January, the hottest two years on record according to NASA, the precipitation is 100% in the form of liquid water rain. It is raining right now outside my window.

I agree folks should check their perceptions against the hard data, and in my case, confirm I am not making this whole "winter" story up. But if you are reasonably attentive and old enough, you may be accurately sensing something is wrong, wrong, wrong.
Mark Thomas
5 / 5 (5) Jan 23, 2017
May, 2016: "India recorded its highest-ever temperature on Thursday when the heat in the town of Phalodi, in the western state of Rajasthan, shot up to a burning 51 degrees Celsius (123.8 degrees Fahrenheit)."

http://www.cnn.co...erature/

http://www.foxnew...ave.html

As the temperature CONTINUES to rise, you can expect a chorus of sad anecdotes from all around the world.
snoosebaum
1 / 5 (3) Jan 23, 2017
Mark , winter just moves around , snow in the sahara and a whole month &1/2 solid winter here in BC which is very unusual and we are not done yet.
Mark Thomas
5 / 5 (4) Jan 24, 2017
snoosebaum, how many years of record heat is it going to take?
HeloMenelo
5 / 5 (3) Jan 25, 2017
if you snooze you lose, an antigoracle sock that snooozes everyday ;)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.