State of the Planet

News from the Columbia Climate School

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Preparing for a Future of Perpetual Drought


The drought that is plaguing much of the country has affected 80 percent of the nation’s agricultural land, making it the most extensive drought since the 1950s. Over 3200 heat record were broken just in June. As of Aug. 1, more than half the counties in the United States had been declared disaster areas. Meanwhile, the Intergovernmental Panel on Climate Change projects that comparable droughts will likely increase in central North America this century.

The U.S. produces about 52 percent of the world’s corn and 43 percent of its soya beans. In July, the Department of Agriculture declared 38 percent of the corn “very poor” or “poor; ” 30 percent of soya beans were rated “poor.”

A Missouri cornfield. Photo credit: Theresa L. Wysocki

The failed crops are pushing world food prices higher, especially prices for meat and dairy products since much of the corn and soya are used for livestock feed.

Rivers are losing water, endangering ecosystems and wildlife, and on the Mississippi River, ships are backed up and must carry less cargo because the water is shallower. The drought’s effect on plants could further exacerbate global warming, by reducing plants’ capacity to absorb CO2.

Richard Seager, Palisades Geophysical Institute/Lamont Research Professor at Columbia’s Lamont-Doherty Earth Observatory, explained that La Niña, a phenomenon of unusually cold ocean temperatures in the Pacific Ocean south of Mexico and Central America, is the main cause of the drought. La Niña pushed the storm track northward so that there has been less snowfall across the U.S. resulting in abnormally dry soil conditions.

“There’s no doubt that this is a remarkable drought because it’s unusual to see so much of the country affected… however, it’s not unprecedented—the U.S. experienced equally serious droughts in the 1930s and the 1950s and before that, too,” Seager said. “…But so many record high temperatures almost certainly have something to do with the background climate change signal.”  Seager’s research projects that southwestern North America and the subtropics will get warmer and drier in years to come due to global warming, and that the aridity experienced during the Dust Bowl and the 1950s will become the new normal by mid-century.

“The future is now,” wrote NASA scientist James Hansen recently in a Washington Post opinion piece. Hansen and his colleagues’ new analysis of the past 60 years of global temperatures contends that “for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.”

How can we prepare for a future of perpetual drought? Upmanu Lall, director of the Columbia Water Center at the Earth Institute, discussed several coping strategies to deal with water scarcity, some of which the Water Center has successfully implemented in other countries.

Water allocation meeting in Ceara. Photo credit: Columbia Water Center

In 2000, the Water Center and the Earth Institute’s International Research Institute for Climate and Society (IRI) launched a project in the Brazilian state of Ceará where people have struggled with extreme climate variability and drought for hundreds of years. Ceará’s wet season lasts from January to June. Before 2000, residents often assumed that the next wet season would be dry based on a largely arid past, and users were allocated limited water based on this assumption.

The Water Center and IRI implemented statistical forecasting to predict river flow for the next season as early as the previous July, and considered an allocation cycle to cover two years. They also brought together the various water user groups representing residents, industry and agriculture, and organized them into a discussion process to determine how to allocate water for the coming year. The user groups made proposals about their water needs for the next season and what they’d be willing to pay for the water under different scenarios of water availability. Their proposals were then run through an optimization model which tested their feasibility; if the proposals ended up drawing more water than would actually be available, user groups would have to renegotiate their needs and compromise. Eventually all the groups were satisfied, with some changing plans or making side deals. For example, if farmers realized a drought was on the way, they could avoid crop loss and decide not to plant that season, selling their water rights to industry instead. Thus a potentially antagonistic situation becomes one in which everyone might benefit. In Ceará, there are already water committees for each reservoir, river basin and state, so this strategy is feasible. It is not practiced in the U.S.

In the U.S., California, Arizona, Idaho and Texas have active water banks, organizations that facilitate the leasing of water between water rights holders and users. The voluntary transactions are based on the current market value of water, a user’s needs, the value of a crop or product needing water, and the cost of the deal. However, because U.S. water banks are not forecast-based, said Lall, they make deals only after a drought begins. Forecasting needs to be integrated into the process, so that people can plan more efficiently, as the water users of Ceará are now able to do.

According to the U.S. Department of Agriculture, agriculture accounts for 80 percent of the consumptive use (water lost to the system through evaporation and not returned to streams or rivers) of U.S. ground and surface water, and over 90 percent in many western states. Most field crops use flood or sprinkler irrigation where a great deal of water is wasted due to over-application. If inexpensive soil moisture sensors were more widely used, “agricultural water efficiency could be increased by about 10 to 15 percent without significant cost,” Lall said.

Installing tensiometers in India. Photo credit: Columbia Water Center

Central Punjab, India suffers from serious groundwater depletion due to excessive irrigation pumping. The Water Center worked with Punjab Agricultural University to identify water-saving strategies for rice cultivation, including the use of tensiometers, affordable tools that measure soil moisture so that farmers know when it’s necessary to water and when it’s not. In a pilot project, 525 farmers who were given tensiometers ended up using 22 percent less water and 24 percent less energy (for irrigation pumping).

In the U.S., billions of dollars are spent purifying water up to drinking water quality when we use only 10% of it for drinking and cooking, then flush the rest down the drain. We should also put more recycled wastewater to use, particularly in urban areas, said Lall.

What the U.S. lacks and what we need, Lall contends, is a national water policy that incorporates forecasts, trading mechanisms, options, and the wise and coordinated management of both surface and groundwater resources to balance one another in wet times and dry.

Agriculture must also adapt to meet the challenges of increased drought. A recent report by the U.S. Department of Agriculture examined how farmers can moderate the impacts of hot and dry conditions by adjusting their crops, rotations, and production practices. Farmers should diversify the types of crops they grow (since monocrops are more vulnerable to disease and pests and economic risk) and the livestock they raise. Agriculture can adapt by adjusting the timing of planting and harvest and changing the distribution of crops, growing crops more vulnerable to heat and aridity in less risky areas. The alternating of fallow and tillage practices can be used to protect moisture and nutrients in the soil.

Crops are being developed that are more heat and drought tolerant; the first genetically engineered drought-tolerant corn hybrids, which have been shown to increase yields by 10-15 percent under stressful conditions, may hit the market in 2013. Scientists are also trying to develop plants that have improved photosynthesis at higher temperatures, plants that respond better to elevated CO2 levels, and crops that are disease and pest resistant since warmer temperatures will increase the incidence of pests and disease. Fortunately, U.S. corn plants have already been bred to be much more drought tolerant than they were 50 years ago.

The Worldwatch Institute’s Nourishing the Planet project also presents strategies to make agriculture more drought-resilient and sustainable.

A micro-irrigation system in Texas.

Agroforestry, planting trees around farms, reduces soil erosion; alternating crops helps restore soil nutrients and control pests; smarter irrigation utilizing water sensors or micro-irrigation technology reduces water waste; and integrated farming practices that are in harmony with the local ecology, such as permaculture and organic farming, increase sustainability. The project also recommends the re-evaluation of ethanol subsidies, which have increased the demand and price for corn and encouraged monocropping.

While not every American feels the direct effects of the drought, we will all eventually feel it in our pocketbooks when food prices rise.  As much of the U.S. faces a future of perpetual drought, we all need to understand the true value of water and conserve it. Here are 100 ways.

For more information about the drought, including up-to-date conditions, forecasting and how to prepare for drought, visit the U.S. Drought Portal.


Banner featuring a collage of extreme heat images.

Recent record-breaking heat waves have affected communities across the world. The Extreme Heat Workshop will bring together researchers and practitioners to advance the state of knowledge, identify community needs, and develop a framework for evaluating risks with a focus on climate justice. Register by June 15

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11 years ago

[…] US needs a national water policy that incorporates forecasts, trading mechanisms, options, & wise […]

11 years ago

[…] summer of 2012 that rendered half of U.S. counties “natural” disaster areas. Despite reports of perpetual drought becoming an increasingly intractable problem in the coming decades, with scientists predicting the […]