NAIROBI – Many people know that oceans cover more than 70% of the world’s surface, and that marine fisheries provide food for billions of people. What is less known is that the high seas – the areas of the world’s oceans that lie beyond the limits of national jurisdiction, which extend 200 miles from shore – make up roughly two-thirds of our oceans and 45% of the planet’s surface.

This area, which contains perhaps the largest reservoir of biodiversity left on earth, is exploited by many countries, but managed by no one. Moreover, it is under extreme pressure. The United Nations Environment Program’s (UNEP) Global Environment Outlook concluded that three-quarters of marine fisheries are exploited up to, or beyond, their maximum capacity. According to the UN’s most recent "State of the World’s Fisheries and Aquaculture” report, 85% of fish stocks are fully exploited or worse – the highest levels ever recorded.

The problem is certainly not a lack of commitments, including those made at the Rio Earth Summit in 1992. Rather, what has been missing is the fulfillment of these commitments.

Governments are once again on the "Road to Rio” for a summit in June 2012 – aptly referred to as Rio+20. Later this month, they are meeting in New York at the UN as part of their preparations for the summit, with a particular focus on oceans. It is an appropriate time to remind ourselves of the commitments made in Rio 20 years ago, and to get on with the process of implementing them. This is true for ecosystems generally, and for oceans in particular.

Much of the current plight of the world’s marine fisheries is a result of subsidized, industrial-scale overfishing. This is imposing an increasing burden on the poor and vulnerable, especially in developing coastal countries and small island states.

The Rio Declaration, issued at the Earth Summit in 1992, recognizes a responsibility to ensure that activities do not damage other states’ environment or that of areas beyond the limits of national jurisdiction. Fisheries depletion, in both exclusive economic zones and on the high seas, reveals how the international community is failing to meet one of the most important commitments that came out of the 1992 meeting.

Further attempts to sustainably manage the marine environment emerged 10 years after the Rio meeting, at the World Summit on Sustainable Development in Johannesburg, South Africa. A series of UN General Assembly resolutions negotiated and adopted since 2004 have also set out regimes to protect the biodiversity of the deep seas. Yet compliance has been patchy at best.

Another approach championed at the Johannesburg meeting was to establish a representative network of Marine Protected Areas (MPAs), including no-take reserves. Last year in Nagoya, Japan, governments agreed to establish such areas in 10% of the world’s oceans by 2020. Currently, such levels of protection apply to only about 1%, so there is a long way to go.

The science relating to fisheries has been clear for decades. Yet governments have consistently failed to heed their own experts’ warnings. Marine management remains a fragmented patchwork of national and international bodies, with separate and often overlapping jurisdictions, and no global accountability. Moreover, in many parts of the world’s oceans, there is no one in charge. This critical shortcoming must be resolved.

One particular impediment is high-seas governance, or the lack thereof. Without internationally agreed-upon mechanisms for designating and managing marine-protected areas in international waters, the commitments made in Nagoya will amount to little more than hollow promises.

Subsidies are another major problem. It is estimated that around $27 billion a year in subsidies to the fishing industry worldwide have generated excess fishing capacity that exceeds by a factor of two the ability of fish to reproduce. In other words, there are twice as many industrial fishing vessels catching fish as the oceans can sustain.

UNEP calculates that investing $110 billion over the coming years in strengthened fisheries management – including the establishment of MPAs, the decommissioning and reduction of fleet capacity, and retraining of workers – will allow the planet’s fisheries to recover. Such an investment, backed by policy measures, would result in an increase in catch levels from 80 million tons now to 90 million tons in 2050, following an initial decline between now and 2020.

The bottom line is that the present value of benefits from "greening” the fishing sector is estimated to be 3-5 times the investment – an excellent return for both people and the ocean environment. Meanwhile, job losses in the short to medium term can be minimized by focusing cuts in capacity on a relatively small number of large industrial vessels, as opposed to small-scale artisanal fleets.

Employment in fisheries in many countries is projected to grow again over the coming decades as depleted stocks recover. Next year’s Rio+20 conference presents a major opportunity to demonstrate that international cooperation through the UN is possible, and that transformational change can be achieved.

The world can no longer afford to delay restoring the health and wealth of the oceans. The half-billion people who depend on a healthy fishing industry, and the one billion who rely on fish as a primary source of protein, cannot wait another 20 years for the international community to act.

Achim Steiner is UN Under-Secretary-General and Executive Director of the United Nations Environment Program. Joshua S. Reichert is Managing Director of The Pew Environment Group.

Copyright: Project Syndicate, 2011.