The Fate of the Ocean
Page 2 of 12
|
|
“The root cause of this crisis is a failure of both perspective and governance,” concludes the seminal Pew Oceans Commission’s 2003 report to the nation. “We have failed to conceive of the oceans as our largest public domain, to be managed holistically for the greater public good in perpetuity.” Instead, we have roiled the waters, compromising the equilibrium that allowed our species to flourish in the first place, and providing ourselves with a host of challenges that will test our clever brains and our opposable thumbs as never before. Afloat on arks of dry land, we sail toward a stormy future.
THE GOAL OF EXPEDITION OC 417 is to sail from Cape Cod two-thirds of the way to Bermuda along a 321-mile-long line known as a transect. We are scheduled to sail outbound nonstop for 36 hours until, 385 miles to the southeast, we’ll begin to work our way back, sampling waters from the surface to the abyss at 22 predetermined stations, identifiable only by their latitude and longitude. In the course of a week, we’ll measure temperature, oxygen, salinity, and chlorofluorocarbons in the water column—the equivalent of taking the ocean’s pulse, listening to its lungs, looking at its tongue, and making it say “ah.”
According to the charts, we are sailing the North Atlantic. But this is a relatively arbitrary marker. In fact, there is only one ocean on Earth: a world ocean encompassing 70.78 percent of our planet. The ancient Greeks sensed the ocean was one and portrayed their water god Okeanos (Oceanus) as a river circling the world. Three thousand years later, modern oceanographers confirm the world ocean is connected in riverlike fashion; using a sche- matic known as the ocean conveyor belt, they portray Okeanos as a Möbiuslike ribbon winding through all the ocean basins, rising and falling, and stirring the waters of the world. In this manner, the surface waters we sail in the North Atlantic are destined to flow to the Arctic, to grow colder and sink, and, once at the bottom, to reverse flow southward through the Atlantic, eventually converging with the Antarctic Circumpolar Current, before surfacing in the Northeast Pacific 1,200 years from now. Centuries later, they will arrive back in the North Atlantic, having truly traveled the seven seas.
Or maybe they won’t. Things are changing.
In 2005, researchers from the Scripps Institution of Oceanography and the Lawrence Livermore National Laboratory found the first clear evidence that the world ocean is growing warmer. In a novel study combining computer modeling and field observations, and screening for natural weather effects and the impact of volcanic gases, they discovered the top half-mile of the ocean has warmed dramatically in the past 40 years as a result, clearly and simply, of human-induced, rising greenhouse gases. “The statistical significance of these results is far too strong to be merely dismissed and should wipe out much of the uncertainty about the reality of global warming,” reported researcher Tim Barnett of Scripps, who suggests the Bush administration convene a Manhattan-style Project to figure out what mitigations might still be possible.
One symptom already manifesting is the melting of the Arctic. Last year set a fourth consecutive record low for ice cover in the Arctic, and scientists now predict the summertime Arctic will be ice-free before the end of this century—a course likely exacerbated by the simultaneous decrease of wintertime Arctic ice. Consequently, the world’s 22,000 polar bears, along with their primary prey, the ringed seals who likewise den on sea ice, are likely to suffer localized or even overall extinction [see “On Thin Ice” by Marla Cone]. Yet the eight nations surrounding the Arctic are rushing to capitalize on the resources emerging from the ice, grabbing for a quarter of the world’s undiscovered oil and natural gas; a trove of gold, diamonds, copper, and zinc; the earth’s last pristine fishing grounds, which are shifting north as fish follow colder waters; and the fabled Northwest Passage and other Arctic travel routes. Even as some governments deny the existence of global warming, they are racing to map the Arctic seafloor and bolster their territorial claims for exclusive economic zones no one cared about 15 years ago.
Reinforcing these entrepreneurial dreams is the reality of a feedback loop already in motion. Compact sea ice, with its high albedo (whiteness), reflects 80 percent of the sun’s heat back into space, while seawater, with a low albedo, absorbs 80 percent. The reduction in the ratio of ice to water further increases the warming of the ocean, which rises from thermal expansion, creating an even greater surface area of water, which promotes further warming and further melting, nibbling away at even more sea ice. In other words, the melting will be difficult if not impossible to reverse anytime soon.
