I’ve been lucky enough to live close to the ocean my entire life. The vastness and beauty of the oceans are a constant source of inspiration. President John F. Kennedy once said, "We are tied to the ocean. And when we go back to the sea - whether it is to sail or to watch - we are going back from whence we came." Water is the source of life, and our fates are intimately linked to the oceans, and to the health of our oceans.

Our oceans provide half the oxygen that makes our planet livable, and in the last decade they absorbed about 30% of the carbon dioxide emitted by industry.

There are 200,000 known species in the oceans and perhaps 2 million more species that scientists believe are still out there waiting to be discovered and named. Billions of people depend on our oceans for sustenance. Almost half of all child mortality is caused by under-nutrition, and fish provides access to healthy nutrients, such as vitamin B12, omega-3 fatty acids. Billions of people also depend on the oceans for their livelihoods. The economic value of the goods and services from the oceans is estimated at $2.5 trillion annually.

But today our vital oceans - the Arctic, Atlantic, Indian, Pacific and Southern, as well as thousands of other waterways - are in serious danger because of the enormous stress placed on them by humans. They are facing enormous threats on multiple fronts, including habitat destruction, over-fishing, climate change and pollution. Reefs once full of vibrant, colourful aquatic life have been suffocated by silt and pollution, and are now overgrown in places with algae. In Hawaii, I’ve watched my favorite snorkeling spot lose 30% of its coral reef from pollution.

By 2050 it is estimated that there will be more plastic than fish in our oceans. There are already more than 5 trillion pieces of plastic pollution circulating in the oceans today. Big pieces of plastic are fragmenting into even smaller microplastics, and working their way into marine food webs, disrupting marine life.

Image: World Economic Forum report, The New Plastics Economy

Climate change, driven by runaway carbon emissions, is the newest and biggest pollution problem the oceans have ever faced. Climate change is causing the oceans to heat up, acidify, and become less well oxygenated. We are slowing changing the oceans into a place where it is tougher for species living on the edge to avoid overheating, hard to build pH sensitive coral reefs, and challenging to breath in.

It is not just ocean wildlife that will be affected. Sea level rise caused by the expansion of our warming oceans and the slow but steady melting of the ice sheets will put large parts of highly populated coastal cities, built up over centuries, underwater.

And, at least a third of fisheries around the globe have been over harvested, decimating fish populations. Bottom-trawling has affected life in about 50 million square kilometers of seafloor. Destructive fishing practices have imperiled the future of some of the most special species in our ocean: the car-sized Atlantic bluefin tuna, the Vaquita, the world’s smallest cetacean, and many species of sea turtles – each of these now as endangered at rhinos.

'This cannot be the legacy we pass on to our children'

This kind of escalating damage cannot be the ocean legacy we pass along to our children. The time to act is now. Scientists warn that if we keep going with our business as usual management of the oceans, we may soon trigger a mass extinction of ocean life that would be unlike anything our planet has ever seen. We can’t let that happen.

The good news from these same scientists is that it doesn’t have to happen. Even though the oceans are badly damaged, they are not damaged beyond repair. I’ve watched how people can pull together to reverse this kind of environmental damage before. In my own ocean backyard, in San Francisco, the bay was once so polluted from industrial waste that the water stank from raw sewage, affecting ocean life and the entire city.

In 1970, the first Earth Day brought 20 million Americans together across the country to bring attention to human activities that were detrimental to the oceans and environment. This led to US Congress passing the Clean Water Act, and today, nearly 50 years after the passing of the bill, the San Francisco Bay is starting to come back to health. A tiny porpoise that hasn’t been seen in the San Francisco Bay since the 1940s is back and reproducing, and a white shark was spotted for the first time ever feeding inside the bay.

Just last month, President Obama established the largest marine protected area in the world, the Papahānaumokuākea Marine National Monument in the waters of Hawaii. This is a section of ocean, over three times the size of California, that is now safe for sharks, manta rays, and sea turtles. These are just the kind of bold actions that scientists are prescribing if we want to stop a marine mass extinction before it starts.

We still have a long way to go, and it’s clear that the costs of inaction in protecting our oceans are just too high. Just as hospitals are funded to come up with treatments and cures for most devastating illnesses, we need the equivalent of hospitals for our oceans that enable marine researchers to turn their science into solutions and their solutions into substantive change.

My wife Lynne and I have been working with Douglas McCauley, an innovative marine scientist at University of California at Santa Barbara, California’s leading research ocean center, on an initiative to create a kind of hospital for the oceans where anyone in the world can submit a problem that is compromising ocean health. A team of the best ocean scientists is assembled to intensely study a selection of these problems and come up with a viable solutions.

We cannot have our brightest minds in marine science using their research to write elegant obituaries for the oceans and their inhabitants – we have to empower them to turn their science into solutions and their solutions in real change. We must forge new kinds of partnerships and work together across governments, nonprofits, academia, business and our local communities in creative new ways to starting fixing the oceans while there is still time.