THE oceans are our planet's new frontier, a huge area only partly explored and little regulated, where both outlaws and law-abiding citizens are legally plundering the planet's resources. While 15% to 20% of the earth's land area is designated as "protected," with status as national parks or conservation areas, less than 1% of the world's oceans - which cover 70% of the surface - enjoy the same protections. This needs to change fast, because our oceans are dying.

At the United Nations (UN) Conference on Sustainable Development that will take place in Brazil on June 20, the Ocean Elders, a group of global leaders who have teamed up to use their influence to promote ocean conservation, will be urging heads of state and high-level government envoys to draw up a mandate that will oblige nations around the world to assume a far higher level of responsibility for the welfare of our oceans. The conference is known as the Rio+20, recognising that 20 years have passed since the first Earth Summit in Rio. At this summit, it is time for leaders to push through real change.

With most of the high seas open to unrestricted fishing, the oceans are being pillaged. One of the worst techniques is dragnet bottom trawling, which involves dragging large, heavy nets across the seabed, destroying corals and sponges vital to ecosystems - effectively strip-mining the oceans of marine life. This indiscriminate trawling is as inefficient as it is destructive: for every kilogram of targeted fish species captured in such a net, about 10kg of so-called "by-kill" (unwanted fish) is killed. It is not surprising that studies by the UN's Food and Agriculture Department showed in 2012 that about a third of fish stocks were overexploited, depleted or recovering.

The more one learns about this marine mayhem, the more terrifying the picture becomes. WildAid estimates that a gruesome total of 1.5-million sharks are being slaughtered every week, just for their fins. This trade is flourishing partly because of the strong economy in China, where some people will pay as much as $100 a bowl for shark-fin soup. According to the International Union for Conservation of Nature's Shark Specialist Group, as many as one-third of all shark species are now threatened with extinction. To its credit, WildAid's tireless efforts have resulted in bans of shark-product sales in several cities, but this does not affect the underlying problem.

And over-fishing and the wholesale destruction of marine ecosystems are not the only man-made threats to our oceans. We usually only pay attention to the garbage we see and recognise, like the 22m-long dock from Japan that recently washed up on an Oregon beach 15 months after the tsunami there, but it is actually the much smaller flotsam that wreaks the most havoc. Over time, the millions of tons of discarded plastic that get dumped in our oceans is broken down by wave action and sunlight to form what becomes a plankton-like plastic soup that fish mistake for food. The fish eat the plastic and, if they survive that, in some instances we eat the fish.

To attack this problem, Doug Woodring, a Hong Kong resident, has followed up on the successful Carbon Disclosure Project, which now boasts more than 3,000 corporate participants, by launching the Plastic Disclosure Project, with the objective of driving greater corporate, community and individual accountability in the manufacture, use and disposal of plastics.

Organisations such as WildAid and people such as Woodring are valiantly doing their bit to draw attention to these multiple threats to our oceans, but we must all help by forcing our elected representatives to take urgent and concrete action. There's a huge expanse of vulnerable ocean out there and it's going to take a lot of well-coordinated policing if we are going to give it the protection it deserves.

In a report written in 1987, an independent commission reporting to the UN defined sustainable development as "meeting the needs of the present without compromising the ability of future generations to meet their own needs." If we can't figure it out now, whales, dolphins, sharks and coral reefs will become the stuff of history lessons for our children's children.

© 2012 Richard Branson. Distributed by The New York Times Syndicate

. Branson is founder of the Virgin Group. He blogs at www.virgin.com/richard-branson/blog. Follow him on Twitter at www.twitter.com/richardbranson. Send questions to branson@bdfm.co.za and include your name, country, e-mail address and the publication.