Why a new UN treaty to safeguard the “high seas” matters

THE OPEN OCEAN, which covers nearly three-quarters of the Earth’s surface, sustains and regulates life on the planet. Each year it sucks in about a quarter of the carbon dioxide emitted by humanity. It is economically valuable, too. The food, shipping, tourism and other activities which rely on the ocean are worth some $2.5trn annually. But almost two-thirds of the ocean lies outside exclusive economic zones, which extend up to 200 nautical miles (370km) from countries’ coasts. That leaves some 219m square kilometres of ocean, known as the “high seas”, outside any national jurisdiction. These areas are vulnerable to plunder by states, businesses and criminals. Two-thirds of fish stocks in the high seas are overexploited, according to the International Union for Conservation of Nature, a network of conservation groups and governments. But there has been no way to tackle these problems—until now. On March 4th negotiators at the UN agreed on the first international treaty to protect the high seas. What might it achieve?