Benefits to Water Scarcity in the United States

Agricultural Biotechnology: Benefits for Water Scarcity in the United States

The scarcity of fresh water is a real and growing concern around the world. The United Nations has predicted that, if present water consumption patterns continue, two out of three people will live in drought or water-stressed conditions by 2025.1

The United States faces similar challenges. Droughts have been a persistent problem in American agriculture for three centuries, and the combination of climate change and population growth in the South and Southwest are serving to exacerbate the situation. 

Water used in irrigating crops accounts for approximately 40 percent of total freshwater use in the United States. It is overwhelmingly the largest and most significant consumer of freshwater because of its high "consumptive use." In contrast with other sectors, such as power generation and public water utilities – which recover, reuse or recycle 90 percent of the freshwater they use – fully half of the water used in irrigation cannot be recovered.2 According to the U.S. Department of Agriculture, agriculture is responsible for between 80 and 90 percent of the country's consumptive use of water. 

Water scarcity is expected to be the single most significant constraint on crop production over the next 50 years,3 and a recent New York Times article warned that, "unless the world changes its ways over the next 50 years. . . a growing water crisis [will] fuel violent conflicts, dry up rivers and increase groundwater pollution."4 

There are two major areas of concern in the United States: (1) the use and continued depletion of surface and groundwater, and (2) the likelihood of continuing droughts, particularly in the West.

Depletion of Surface and Groundwater

The freshwater used in agriculture is currently 58 percent surface water and 42 percent groundwater. Reliance on water pumped from groundwater stores – called aquifers – has increased dramatically since 1950, when it accounted for only 23 percent of the water used in irrigation, with surface water providing the rest. This trend toward ever greater dependence on groundwater is expected to continue. 

The High Plains Aquifer, one of the world's largest sources of groundwater, stretches from Texas to South Dakota. It provides water to eight agriculturally important states – and is the most heavily pumped aquifer in the country. Depleting an aquifer at a rate greater than it can replenish itself – known as overdrafting – can cause sedimentary deposits to build up, eventually making it impossible to extract any more water from it. Recent studies have shown that the highly productive farming region of western Kansas will no longer be able to pump from this aquifer in 50 years,5 and portions of Arkansas could be in danger as soon as 2015.6

Moreover, surface and groundwater are interrelated. Nearly half of river flow nationwide depends on groundwater,7 for example, and excessive pumping of groundwater can actually change the flow and direction of rivers.

Given these dynamics, it is not surprising that California farmers, who previously depended on the Central Valley Aquifer, have resorted to importing water from other parts of the country. It is also not surprising that Federal and state policymakers are putting an increasing emphasis on "groundwater sustainability." 

Drought

The depletion of surface and groundwater is closely connected to drought. Between 1980 and 2005, the United States experienced nine "drought events" – each of which cost the economy an estimated $1 billion or more. According to some estimates, the 1988-1989 drought may have cost the country as much as $40 billion.8 

Several regions in the United States currently suffer from persistent drought conditions, particularly the Southwest and Southeast, and many other parts of the country have recently experienced drought conditions as well. The West is expected to suffer historic drought conditions in the coming decades, and climate change may alter a significant portion of winter precipitation in some regions from snow to rain: earlier spring thaws would mean longer droughts during the peak summer growing season.9

The Role of Agricultural Biotechnology

Recent developments in agricultural biotechnology are already helping farmers cope with water shortages, and ongoing research holds the potential for even greater advances. Researchers are focusing on developing plant varieties that have one, or both, of these beneficial qualities:

• They are able to thrive and produce food under drought conditions; and
• They can be grown using the conservation practice known as "no-till agriculture" – the practice of leaving much or all of the crop residue in the field, which vastly improves absorption and conservation of water from rainfall and irrigation.

Crops that thrive in drought conditions

Researchers are developing food plant varieties that use water up to two or three times more efficiently; that are able to recover, regrow and produce food following a prolonged lack of water; and that produce the same yield under drought conditions – defined as a 70 percent reduction in water – as under normal conditions.

No-till agriculture

Tillage, or plowing, which farmers have historically used to control weeds, can cause significant runoff and erosion, wasting precious water and reducing yields. Since the introduction of herbicide-tolerant biotech crops in 1996, the practice of no-till agriculture has increased by 35 percent.10 

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