Papah?naumoku?kea Marine National Monument in Hawaii is now the world’s largest marine protectedarea. It’s an area like a national park that’s closed off to commercial extraction and fishing. But we can do more when it comes to protecting our water.The National Park Service was created over a hundred years ago to conserve areas of natural, cultural and historic importance and leave them “unimpaired for the enjoyment of future generations.” Back then it was a radical idea to put large tracts of land into federal custody. Now, there are calls for greater protective expansion to the ocean.The challenge is real. Nearly three-fourth of the globe is covered by ocean which produces more than half the oxygen in the atmosphere. Many fish—tunas, swordfish, marlin, sharks, cod, and halibut—and other ocean wildlife have become extinct, and fisherman plead for permanent safe havens where fish and the ecosystems that support them can recover. Ocean acidification, driven by dumping waste and excess atmospheric carbon dioxide, is changing ocean chemistry.Scientists tell us at least 30 to 50 percent of the ocean must be fully protected to restore its health. Today, only about 2 percent of the ocean is protected from destructive activities including industrial-scale fishing and mining, while the land has received seven times that amount of protection. More ocean has been set aside for protection in the past 18 months than during any other period in history, with announcements of new marine reserves by the governments of the U.S., the United Kingdom, New Zealand, Chile, and Palau. Even with these successes, only about 3 percent of the world’s ocean has been set aside with strong protections.But the benefits of additional national parks and safe zones are tangible, and additional parks must be created. Studies have shown that ocean sanctuaries, also known as “no take” marine reserves, quadruple the biomass of animals and plants and also vastly increase their size. They also serve as breeding grounds for threatened species, such as whales and marine turtles, as well as protect marine ecosystems and the biodiversity they sustain.Scientists have also shown that ocean sanctuaries can boost local economies. In a recent investigation by National Geographic, researchers found that inside ocean sanctuaries there is often a boost in tourism, and they help benefit fisheries outside of the areas. Initial costs for developing the reserve can therefore be made up for in as short as five years. It is politically possible to set aside extensive areas where extractive industries such as fishing, mining and oil exploration are forbidden. And establishing large ocean sanctuaries in the high seas is likely to lead to a fairer distribution of marine resources, where many coastal states, including the world’s least developed countries, would benefit the most. Sanctuaries also increase the resilience of the ocean against the impacts of climate change and ocean acidification. Over half of the biological carbon stored globally is stored by living marine organisms. Areas that protect salt marshes, mangroves, and algal and seagrass beds, all of which store carbon, therefore help mitigate climate change impacts.The time is now to create an ocean legacy for future generations. Bipartisan progress has been made in the U.S., and it is time to capitalize on a “new wave of parks” around the world.