Most environmental problems are concentrated in the area where the pollution is produced. This is good, because it's a lot easier for a single city or country to deal with an environmental challenge than it is for the international community.
There are two huge exceptions to this. The first is global warming, which (as the name implies) affects everyone. The second is the world's oceans, most of which are not claimed as the territory of any nation or the property of any individual. For this reason, they suffer from what economists call the tragedy of the commons. Each actor has an incentive to consume as much of the oceans' bounty as they can, since they know that if they don't, someone else will. The inevitable result is that unless something is done, the world's seas -- home to more than half of the planet's life — will be irrevocably despoiled.
The most immediate global oceanic threat comes from overfishing. As early as 2011, it was estimated that 90% of fisheries were either fully exploited or overexploited.
By some estimates, the number of fish in the oceans has declined by half since 1970. This represents a loss of biodiversity, as well as a threat to a major source of protein consumed by humans. One culprit is the subsidies that countries -- most of them in East Asia -- give to their fishing fleets. Beyond ending these subsidies, the main weapon against overfishing is catch shares, a cap-and-trade program for fisheries that has been successful at restoring the health of many fisheries in the U.S.
Another problem is plastic. In developed countries, almost all plastic goes to landfills (which has its own environmental issues), but in some developing countries it gets littered or tossed into open dumps, where about 8 million tons a year makes its way into rivers and from there into the ocean:
Once in the oceans, the plastic tends to collect in huge garbage patches, where it contaminates the water and harms wildlife. Some of it eventually washes up on beaches, despoiling natural beauty.
Other threats to marine life include chemical runoff from shores and noise pollution from ships.
Then there's carbon, perhaps the biggest problem of all. Climate change is heating the oceans, destroying coral reefs and other ecosystems. But the oceans also absorb about 30% of the carbon that humans emit. While that helps to slow down global warming, the carbon combines with water to make carbonic acid. As one might expect, the acidification tends to be bad for sea life.
From a conservation standpoint, the wholesale destruction of ocean life is an immense tragedy. But to most humans, it represents little direct threat. If most or all of the animals in the seas die, humanity can fall back on aquaculture for our sushi and salmon filets.
Meanwhile, marine pollution doesn't directly affect our daily lives like pollution of air, rivers and groundwater does. In other words, it's unsurprising that people view the oceans as a convenient dumping ground. The uncounted marine creatures that choke to death on plastic or perish in heated acidic waters remain out of sight and out of mind.
But if we intend to be responsible stewards of this planet, we can't let this happen. In addition to potentially causing wrenching problems on land somewhere down the line, the death of Earth's oceans would be an unforgivable moral stain upon the human species.
Stopping this, however, will require international action. Rich countries already bury most of their plastic trash, and the U.S. has made headway in preventing overfishing. Carbon emissions, meanwhile, are a global phenomenon. Saving the oceans thus means changing the behavior of developing countries such as China, as well as rich East Asian countries like Japan and Taiwan, which have less rigorous conservation standards.
The U.S. and other countries that care about the health of the oceans can do several things to spur the biggest offenders to change. First, trade policy can be rewritten to take ocean damage into account — the U.S. should be able to apply tariffs on goods from countries that overfish and dump plastic into the seas. Second, the U.S. should use the UN and other international organizations to coordinate international policies and standards to save marine life. Finally, the U.S. should use a variety of measures to help developing countries switch to carbon-free energy sources.
The oceans may seem unimportant to many, but they're an irreplaceable part of the living planet. Letting them die out of neglect and lack of coordination is not an option.
Disclaimer: This article first appeared on Bloomberg.com, and is published by special syndication arrangement.