How to Think About Oil Spills
The perils of overreaction.
Jun 21, 2010, Vol. 15, No. 38 • By STEVEN F. HAYWARD
The ecological effects of the Ixtoc 1 disaster should be borne in mind when we hear claims that the Deepwater spill will inflict large and long-lasting effects. According to a 1981 study by the Royal Swedish Academy of Sciences, about half of the Ixtoc 1 oil evaporated, and another 25 percent sank to the bottom of the ocean, much of it broken up by wave action and chemical dispersants. The Swedish Academy study estimated that oil from the Ixtoc 1 poisoned a 5,800 square mile area, devastating crab, shrimp, and fish stocks, and leading to large oxygen-killing plankton blooms. Overall fish landings fell by up to 70 percent in Mexican and Texan coastal waters. On the other hand, the 5,800 square mile area represented about 2.5 percent of Mexican Gulf Coast waters. Finally and most ironically, Hurricane Frederick struck the Texas coast in September 1979, and washed away 95 percent of the oil that had reached shoreline beaches and marshes. The current fears of the effects of tropical storms and hurricanes in the midst of the Deepwater spill might be misplaced.
It will be some time before we have a precise idea of the nature and extent of environmental damage from the Deepwater spill. It should be borne in mind, however, that ocean ecosystems tend to have faster recovery times than ecosystems on land, owing to the area available for the dilution and dispersal of the oil droplets, the constant aerating turbulence of ocean waters, and the ease of repopulation from adjacent areas once the anoxia (lack of oxygen) has passed.
A recent study of seven basic ecosystem types, and their most typical perturbations, found that of ecosystems that make a recovery from various catastrophic events (and, it must be noted, not all do), ocean ecosystems disrupted by oil spills were the fastest to recover, often within a span of one to four years. As the New York Times noted in a 1993 story, the Persian Gulf recovered surprisingly faster than anticipated from the 1.2 million ton spill Saddam Hussein engineered in 1991: “The vast amount of oil that Iraqi occupation forces in Kuwait dumped into the Persian Gulf during the 1991 war did little long-term damage, international researchers say.” By contrast, forest lands disrupted by fire or deforestation can take more than 40 years to recover.
Besides increasing our reliance on tankers, there are two other reasons curtailing offshore production in the Gulf may not reduce the ecological risk to the Gulf Coast. First, other nations are unlikely to curtail their own offshore exploration in the Gulf. Cuba is drilling for oil within 100 miles of south Florida; Mexico has extensive drilling operations in the Gulf (and as mentioned above caused the largest single spill in history). Both Venezuela and Brazil are expanding their offshore exploration and production in deep water, and are likely to expand to the Gulf of Mexico if the United States scales back.
Second, while the Deepwater Horizon spill represents an acute short term shock to Gulf waters and the Gulf Coast, the chronic seasonal depletion of oxygen in the Gulf (aka the 8,500 square mile “dead zone” below the Mississippi River Delta) may be aggravated by one of the policy responses that has been suggested in the aftermath of the Deepwater Horizon: increased ethanol production. The Nebraska Corn Growers Association has been especially enthusiastic, offering several tweets such as “Offshore oil drilling far from fail safe. The spill will boost the appeal of renewable energy, such as ethanol. . . . There is a fuel option that doesn’t result in oil spills in the ocean. It’s known as ethanol. . . . When was the last time you saw a headline for an ethanol spill in the ocean?”
Actually, it is possible to point to an ethanol-related environmental calamity in the Gulf every year. Hypoxia—oxygen depletion—in the Gulf fluctuates from year to year depending on a range of variables, but over the long term has gotten worse. A major contributor to this trend is dissolved inorganic nitrogen runoff from the Mississippi River basin, basically surplus fertilizer, which will increase with additional ethanol production.
Recent Blog Posts