The threats from oil spills: now, then, and in the future

Abstract

The ongoing oil spill from the blown-out well by the name of Macondo, drilled by the ill-fated rig Deepwater Horizon, has many features in common with another blowout in the Mexican Gulf that happened three decades ago. Then the oil gushed out from the Ixtoc I well drilled by the Sedco 135-F semi-submersible rig. In the years between these catastrophes, the source and nature of oil spills have undergone large changes. Huge spills from tankers that ran aground or collided used to be what caught the headlines and caused large ecological damage. The number and size of such accidental spills have decreased significantly. Instead, spills from ageing, ill-maintained or sabotaged pipelines have increased, and places like Arctic Russia, the Niger Delta, and the northwestern Amazon have become sites of reoccurring oil pollution. As for blowouts, there is no clear trend with regard to the number of incidences or amounts of spilled oil, but deepwater blowouts are much harder to cap and thus tend to go on longer and result in the release of larger quantities of oil. Also, oil exploration and extraction is moving into ever-deeper water and into stormier and icier seas, increasing potential risks. The risk for reoccurring spills like the two huge Mexican Gulf ones is eminent and must be reduced.

Fig. 1

The Gulf of Mexico in 3D perspective indicating the location of the two marine blowouts. Source: NOAA (http://oceanexplorer.noaa.gov/technology/tools/mapping/media/gis_gulf.html)

Fig. 2

Ixtoc I, 1979. The booms were not very effective. Oil is shown on both sides of the boom (photograph by Olof Lindén)

Fig. 3

Main oil leak at end of riser pipe/12 in. Wrench and ROV in background. © BP p.l.c

Fig. 4

Oil on the surface of the water in the Gulf of Mexico May 17, 2010. © BP p.l.c

Fig. 5

Oil on the Persian Gulf during the 1991 Gulf War. A very thick layer of oil on the sea and part of the beaches formed as a smooth, black surface reaching as far as the eye could see. Smoke from the burning oil wells (not visible in photo) reduced visibility region-wide

Fig. 6

U.S. Fish and Wildlife Service officials look for oiled wildlife on various small islands near Grand Isle, Louisiana, on June 14, 2010. No oiled wildlife were found or recovered on this particular excursion. © BP p.l.c