Ethanol, Global Warming and the Ailing Gulf

The dead zone in the Gulf of Mexico could reach a new record size this year, and grow to cover an area equal to the State of New Jersey, researchers said Tuesday.

One prime culprit: The record Midwest flooding that caused the Mississippi to swell. The discharge of pollutants and nutrients from the Mississippi River causes algae to bloom in the Gulf of Mexico. When the algae dies, the decaying absorbs so much oxygen from the water that large areas become inhospitable to fish. The resulting lifeless area is called a eutrophic or hypoxic zone, or more colloquially, a dead zone. The condition is cyclic, and reaches its maximum in late summer.

The biggest dead zone on record was in 2002, when 8,481 square miles of water became lifeless. Last year, researchers also predicted a record was possible, but the dead zone reached 7,903 square miles. This year, the total could exceed 8,800 square miles, or 5% greater than the last record.

Researchers emphasized the exceptional flow of water from the Mississippi as a prime driver of their prediction, but the other major reason is the use of fertilizers on farms across the Midwest. In 50 years, since the advent of modern agricultural techniques and changes to federal farm policy, farmers have increasingly planted more corn per acre, which depletes the soil and requires heavier inputs of chemical fertilizer. Most nitrogen fertilizers are derived from natural gas, so they are essentially a fossil fuel for food.

The acreage of corn planted, and the use of fertilizer, has skyrocketed in the past couple of years as Congress set quotas on the use of ethanol, an alternative fuel that in the United States is made primarily from corn. As requirements to use more ethanol increased, so did corn acreage and fertilizer used.

Ethanol is seen as a valuable alternative to gasoline, but making it from corn has proved problematic because it takes so much land, drives up food prices by siphoning off corn for fuel use, leads to additional pollution and provides little more energy than it takes to produce. More promising plant sources of ethanol are being studied, including switchgrass, which can be used to make cellulosic ethanol. Biofuels are seen as a promising alternative to gasoline in part because the growing of crops absorbs some of the carbon emitted by burning the fuel, making them a more sustainable option than digging up long-buried hydrocarbons and putting them in the atmosphere.

The record flooding in the Midwest was attributed by many to global warming. At least, many scientists -- including those in federal agencies -- agree that this type of flooding is going to become more frequent and intense as the climate heats up.

So the dead zone in the Gulf of Mexico, which robs fishermen of valuable fishing grounds and harms or kills wildlife, can be seen as another consequence of global warming. In this case, a proposed solution to global warming is also fueling a serious environmental problem.

The world is getting familiar with the carbon cycle and how pumping carbon that's been buried for millions of years into the atmosphere causes some global problems, but the out-of-whack nitrogen cycle is just as problematic.

The World Resources Institute recently mapped the world's dead zones and found a whopping 415 eutrophic (nutrient-saturated) zones, including 169 that are known to be hypoxic (devoid of oxygen) and another 169 that probably are. The researchers believe the number is much higher, since only the United States and the European Union do an adequate job of counting and reporting problem coastal areas. China and other fast-growing Asian economies are likely polluting their coasts, but the problem hasn't been documented, the researchers say.

WRI

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