New study predicts rising irrigation costs, reduced yields for US corn

Jun 03, 2013
Two maps simulate irrigation needs (top) and yields (bottom) anticipated for ethanol corn crops in the 2050s if predicted climate changes come to pass. Red indicates a detrimental effect, where irrigation needs would increase and yields would decrease. The study led by researchers at Rice University and the University of California at Davis appears in the journal Environmental Science & Technology. Credit: Rosa Dominguez-Faus/UC Davis

If the climate continues to evolve as predicted by the Intergovernmental Panel on Climate Change, the United States stands little to no chance of satisfying its current biofuel goals, according to a new study by Rice University and the University of California at Davis.

The study published online in the American Chemical Society journal Environmental Science and Technology suggests that in 40 years, a hotter planet would cut the yield of corn grown for ethanol in the U.S. by an average of 7 percent while increasing the amount of irrigation necessary by 9 percent.

That could sharply hinder a mandate set by the and Security Act of 2007 (EISA) that by 2022 the nation derive 15 billion gallons per year of ethanol from corn to blend with conventional motor fuels, according to principal investigator Pedro Alvarez, the George R. Brown Professor and chair of Rice's Civil and Environmental Engineering Department. Alvarez is a member of the Science Advisory Board of the U.S. and chair of Rice's Energy and Environment Initiative.

The policy is based on the idea that blending ethanol into gasoline cuts from vehicles and lowers the nation's dependence on foreign oil, he said. But the cost in may outweigh those concerns.

"Whereas biofuels offer a means to use more renewable energy while decreasing reliance on imported oil, it is important to recognize the tradeoffs," Alvarez said. "One important unintended consequence may be the aggravation of by increased irrigation in some regions."

The authors of the new paper have long questioned the United States' support of biofuels as a means to cut . In a 2010 white paper on U.S. biofuels policy produced by Rice's Baker Institute for Public Policy, authors including Alvarez and Rice alumna Rosa Dominguez-Faus found "no scientific consensus on the climate-friendly nature of U.S.-produced corn-based ethanol" and detailed what they saw as economic, environmental and logistical shortcomings in the EISA.

Their 2009 feature article in suggested the amount of water required to bring biofuels to market may be prohibitive; they calculated it takes 50 gallons of water to grow enough Nebraska corn to produce the amount of ethanol needed to drive one mile.

They suggested at the time that potential consequences to the water supply needed further study. With the new research, they have taken on that challenge and tied their models to estimates of how climate change—reflected in predicted regional levels of atmospheric carbon dioxide, temperature and precipitation—could affect agriculture in the nation's heartlands.

The team built computer simulations based on crop data from the nation's top 10 corn-producing states – Iowa, Illinois, Nebraska, Minnesota, Indiana, Ohio, South Dakota, Wisconsin, Missouri and Kansas. They also used estimates of carbon dioxide, a greenhouse gas, and other elements from a number of models, including the government's well-tested Environmental Policy Integrated Climate (EPIC) model. They used the simulation to predict crop outcomes over the next 40 years in relation to expectations of climate change.

The researchers found states in the Corn Belt (Iowa, Illinois, Indiana, Ohio and Missouri) and the Great Lakes (Minnesota and Wisconsin), where corn growth is primarily fed by rainfall, would be subject to more intense but less frequent precipitation, especially during the summer. Maintaining crops would require a 5 to 25 percent increase in irrigation, which would in turn require more extensive – and expensive – water catchment infrastructure.

On the Northern Plains of South Dakota, Nebraska and Kansas, where the growth of corn for ethanol already depends heavily on irrigation, the study found that crop yields would decline even if irrigation continued to be "applied as needed," the researchers wrote. In fact, the 2012 drought has already damaged Great Plains farmlands where long-reliable aquifers used for irrigation are beginning to run dry.

The researchers said agriculture costs the water supply in two ways: through the drawdown of groundwater from irrigation and through loss to the atmosphere via evapotranspiration (ET), by which water moves through plants and evaporates. Higher atmospheric temperatures increase ET at a cost to groundwater, they wrote.

The production of one liter of gasoline requires three liters of water, according to the researchers. The production of one liter of corn ethanol requires between 350 and 1,400 liters of water from irrigation, depending on location. A liter of ethanol also translates into 1,600 liters of ET water that might not directly replenish the local watershed.

The researchers suggested the growth of crops for ethanol was already questionable because of its impact on the environment. Rising temperatures in the decades to come, they wrote, could lead to reductions in crop yields and an increase in irrigation demands to the degree that the government mandate is no longer economically viable.

"The projected increases in water intensity due to climate change highlight the need to re-evaluate the corn ethanol elements of the Renewable Fuel Standard," Dominguez-Faus said.

Dominguez-Faus, lead author of the paper, is a postdoctoral researcher at the University of California at Davis. Co-authors are Christian Folberth of EAWAG Aquatic Research, Dübendorf, Switzerland; Junguo Liu, a professor at the School of Nature Conservation, Beijing Forestry University; and Amy Myers Jaffe, executive director of energy and sustainability at the UC Davis Institute of Transportation Studies.

Explore further: Dog waste contaminates our waterways: A new test could reveal how big the problem is

More information: pubs.acs.org/doi/abs/10.1021/es400435n

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User comments : 18

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dogbert
3 / 5 (20) Jun 03, 2013
Ethanol for fuel replacement has always been a bankrupt process. It remains bankrupt without regard to climate change.

We are pumping water from deep aquifers which are not being replaced for the production of fuel.

Diverting food and water to the production of fuel is simply insane.
CharliePeters
3.8 / 5 (9) Jun 03, 2013
GMO corn fuel alcohol stinks.
ScooterG
2.1 / 5 (14) Jun 03, 2013
What sense does it make to burn energy to pump water from underground to irrigate tillable soil to grow corn in order to make motor fuel?

Only short-sighted enviro-dolts think biofuel is a good idea. Enviro-dolts consistently confuse activity with accomplishment.
TheGhostofOtto1923
2.8 / 5 (8) Jun 03, 2013
Ethanol for fuel replacement has always been a bankrupt process. It remains bankrupt without regard to climate change.

We are pumping water from deep aquifers which are not being replaced for the production of fuel.

Diverting food and water to the production of fuel is simply insane.
Expensive food is one way of restricting population growth which is the most significant threat to the world.
Jimee
3 / 5 (2) Jun 04, 2013
While it remains to be seen whether a viable source of bio-derived fuel will be found, it was the corn lobby and greed that pushed for the law requiring ethanol, not caring about the poor or environmentalists' concerns.
gregor1
1.3 / 5 (12) Jun 04, 2013
The IPCC predictions have never been even close to being right so why should we worry about this at all. No connection has been demonstrated between rising Co2 and drought at all in fact the fertilizing effect of extra Co2 appears to partially ameliorate the effects of drought.
http://hockeyscht...tes.html
@Otto population growth is only going to be a problem is the big green multinationals manage to restrict the access of developing nations to cheap and abundant energy. There is an inverse relationship between population growth and energy consumption in fact, one could argue, that fossil fuels have led to an unprecedented greening of the planet as forests are no longer demolished to provide energy for cooking. heating and industry.
gregor1
1.4 / 5 (11) Jun 04, 2013
Cont.
A link for the relationship between energy consumption and fertility rate.
http://www.paulch...ergy.jpg
VendicarE
1.8 / 5 (6) Jun 04, 2013
It won't be long before America will be unable to feed itself.

As a nation, it is already incapable of thinking for itself, or producing it's own material goods.
TheGhostofOtto1923
2 / 5 (4) Jun 04, 2013
It won't be long before America will be unable to feed itself.

As a nation, it is already incapable of thinking for itself, or producing it's own material goods.
Dont worry. I am sure canada will save us. You have amber waves of grain too, yes?
antigoracle
1.9 / 5 (13) Jun 05, 2013
Really!! These morons are still talking about corn as a biofuel.
If these idiots have their way, you'll have no water, no food and a lot more CO2 in the atmosphere
Howhot
3.9 / 5 (7) Jun 05, 2013
You deniers are such idiots. The article isn't about whether corn will be used for ethanol as a biofuel. Its about drought conditions that will disrupt ANY farming in those areas. There is a lot of versatility in crops planting, with most farmers taking large risks in the selection of the crop for the year. If corn only comes in a $1.45 per bushel, vs $4.22 for wheat, It can make or break the farmer. Most farmers that I know are very concerned about global warming and are reading the tea leave trying to get a leg up on these new conditions. Reports like this one, might make you plant something more drought resistant.

antigoracle
1.9 / 5 (13) Jun 06, 2013
You deniers are such idiots. The article isn't about whether corn will be used for ethanol as a biofuel. Its about drought conditions that will disrupt ANY farming in those areas. There is a lot of versatility in crops planting, with most farmers taking large risks in the selection of the crop for the year. If corn only comes in a $1.45 per bushel, vs $4.22 for wheat, It can make or break the farmer. Most farmers that I know are very concerned about global warming and are reading the tea leave trying to get a leg up on these new conditions. Reports like this one, might make you plant something more drought resistant.


I'm not even going to ask if you can comprehend, because you obviously do not possess the capacity to read. If anything, this study confirms the stupidity of the AGW Alarmist cult in even considering corn as a biofuel.
Howhot
3.3 / 5 (7) Jun 07, 2013
I'm not even going to ask if you can comprehend, because you obviously do not possess the capacity to read. If anything, this study confirms the stupidity of the AGW Alarmist cult in even considering corn as a biofuel.


Anti if you even understood 1/2 of what I just said I would be amazed. Big Agri is who ultimately decides what crop will be pushed. Biofuels are certainly carbon neutral and so by using ethanol as a 10% additive, you have reduced the addition of 10% of the CO2 emissions from oil. (unless you have one of these Flex-fuel engines and can do 85% ethanol). Anyway its reduction of CO2 by the economy of the masses. That is the *AGW Alarmist Cult* idea behind it. In addition the Big Agri loves it because it helps stabilize high corn prices and the Gov loves it as it is homegrown energy and supports energy independence.

SO... What is your beef? Farms use water?

Neinsense99
2.8 / 5 (9) Jun 08, 2013
Ethanol for fuel replacement has always been a bankrupt process. It remains bankrupt without regard to climate change.

We are pumping water from deep aquifers which are not being replaced for the production of fuel.

Diverting food and water to the production of fuel is simply insane.
Expensive food is one way of restricting population growth which is the most significant threat to the world.

Education is another way with more pleasant consequences.
VendicarE
2.3 / 5 (3) Jun 08, 2013
"You have amber waves of grain too, yes?" - Otto

Canada has some, but it is already in full production. Thanks to the scouring action of glacial flow, the northern regions have no real soil on which to increase production.
VendicarE
1 / 5 (2) Jun 08, 2013
"Education is another way with more pleasant consequences." - Neinsense

REPORT: HOMESCHOOLING GROWING SEVEN TIMES FASTER THAN PUBLIC SCHOOL ENROLLMENT

http://www.breitb...-Schools
antigoracle
1.7 / 5 (6) Jun 09, 2013
Biofuels are certainly carbon neutral

Give us a single example.
dogbert
1 / 5 (6) Jun 09, 2013
Biofuels are certainly carbon neutral


Perhaps, if you fail to count the energy used to plant, fertilize, water, harvest, transport, cook, ferment, distill and transport to market.