What’s Happening in the Ocean, and Why It Matters to You and Me

Over the last five decades, we’ve burned enough coal, gas and oil, cut down enough trees, and produced enough other emissions to trap some six billion Hiroshima bombs’ worth of heat inside the climate system. Shockingly, though, only 1 percent of that heat has ended up in the atmosphere.

As extreme as the “global weirding” we’re experiencing today is—people broiling under weeks of heat waves, wildfire smoke turning the skies orange, crops withering in prolonged drought, intense downpours inundating homes—most of it results from only a small fraction of all the heat that’s been building up in the climate system.

Instead, the majority of that estimated 380 zettajoules of heat, nearly 90 percent of it, is going into the ocean. There, it’s setting ocean heat records year after year and driving increasingly severe marine heat waves. The ocean also absorbs about 30 percent of the carbon humans produce, adding up to almost 200 billion tons since the industrial revolution.

As humans, we often rely on an “out of sight, out of mind” mentality to prevent the paralysis of worrying about too many things at one time. Yet when we ignore a problem for too long, it can escalate; and that’s exactly what’s happening with our ocean. Climate change’s impacts on the ocean are so massive that when I’m asked why we aren’t talking about it more, the only answer I can think of is, “Because we aren’t polar bears or corals.” If we all lived on or in the ocean, the catastrophic changes we’d be seeing there would dominate our headlines daily.

Even on land, we are already experiencing the impacts of ocean warming. Nearly half the observed increase in sea level over the last century was caused by the thermal expansion of the ocean; as water warms, it takes up more space. Warmer ocean temperatures also power stronger atmospheric rivers, hurricanes, typhoons and tropical cyclones that dump greater amounts of water. They’re altering ocean currents and weather patterns, increasing evaporation so when it rains, it rains harder. And they’re harming marine ecosystems: bleaching coral reefs that support an estimated 25 percent of the ocean’s biodiversity; exacerbating algal blooms that trigger fish kills; and driving the poleward migration of marine species. These migrants range from the phytoplankton that produce at least half the oxygen we breathe, to the fish and shellfish stocks on which more than three billion people depend for their primary source of protein.

The most effective way to reduce these risks is to eliminate the unsustainable human actions responsible for them in the first place. With such massive changes already underway, however, it’s also essential to do everything we can to foster the ability of the ocean’s ecosystems to cope. This includes protecting unique marine habitats, reducing the other ways we’re putting stress on the ocean and its inhabitants, and helping fish, plants and coral adapt to the rapidly changing conditions. The good news is that people are coming up with many creative ways to do this.

Globally, the Nature Conservancy (TNC), which I serve as chief scientist, has the goal of conserving more than 10 percent of the world’s ocean area by 2030. One of the biggest levers it’s using is finance: bringing together governments and lenders to refinance a country’s debt, typically with lower interest rates. These innovative win-win arrangements generate new funding to help countries implement their biodiversity and climate commitments.

Last September, for example, TNC developed a project with Barbados to help the island nation protect up to 30 percent of its marine area. The savings will allow the government to channel $50 million into conserving marine areas and help Barbadians become more resilient to climate impacts. Since the late 1980s, over 140 countries have negotiated refinancing or debt forgiveness agreements to support conservation efforts on land and water. The most recent was in May, when Ecuador secured a “debt-for-nature” deal to preserve the waters around the Galapagos Islands. These projects are a win-win; but many more are needed to meet the Kunming-Montreal Global Biodiversity Framework goals of protecting 30 percent of the world’s land, ocean and fresh water by 2030.

Unsustainable commercial fishing practices put ocean ecosystems and the livelihoods of those who depend on them at risk. Not only that, but in areas such as the Pacific islands where fishing is a big part of the economy, the lions’ share of the profits typically go elsewhere. Pacific Island Tuna, a joint venture of TNC and the Republic of the Marshall Islands, aims to change that. It has contracted directly with Walmart, the world’s largest retailer, to supply canned skipjack tuna for its Great Value brand. The venture uses fair and sustainable fishing practices that prevent overfishing and are fully monitored and verified. Profits will be directed back to the Marshall Islands, with at least 40 percent being invested in community-based conservation and climate resilience projects, including creation and management of marine protected areas (MPAs) and coral reef restoration.

Protecting ocean areas and reducing stressors such as plastic pollution, raw sewage and overfishing is important; but it’s also essential to do everything we can to help ecosystems become more resilient to warmer conditions. Here, coral reefs offer an intriguing possibility. It turns out that some “super reefs” are managing to thrive in warmer waters. By studying them, researchers from the Woods Hole Oceanographic Institution, Stanford University and TNC hope to figure out how to help other reefs survive, too.

Scientists working on this Super Reefs initiative use computer modeling to identify potential super reef locations. Next, divers collect samples that are analyzed to identify coral that can withstand warmer conditions. This informs the design of effective MPAs, which can then be financed by debt-for-nature deals, sustainable fishery initiatives like Pacific Island Tuna, or other programs. Ensuring an area is protected increases the effectiveness of local reef conservation and restoration projects, such as establishing nurseries of “super corals” to restock surrounding reefs.

I recently visited a successful community-led coral nursery initiative at Laughing Bird Caye National Park. It was supported by a debt refinancing agreement for the country of Belize. Equipped with masks and snorkels, we followed a local conservationist out to where a coral nursery, consisting of a framework of interconnected metal poles, was laid out in a sandy area on the ocean floor. The coral was grown on these frames and, once it reached a certain size, transplanted around the island. Today, thanks to the efforts of Fragments of Hope, other community partners and the government of Belize, the caye is surrounded by abundant staghorn coral and serves as an example of the power of local conservation.

Protecting the ocean and its ecosystems won’t be enough, however, if we don’t tackle the root causes of climate change, pollution and biodiversity loss. That’s why it’s essential that we learn how to value the resources nature provides and how to live sustainably on our shared planet. Our problems are all human-caused, originating on land; and that means they can and must be solved by humans living on land, too.

As we begin to understand the vast impact our choices have on the ocean and, consequently, on us, the need for urgent action becomes even more apparent. We can’t afford to ignore the irreplaceable role and indispensable services it provides. It’s still possible to shape a future where people and the ocean can thrive together; but to do so, we must act now.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.