On Restoring the Oceans

Global Reset / by Enric Sala & Kristin Rechberger /

Earth’s oceans are in trouble. But the 2010 Census of Marine Life—the first ever attempt to document all that lives in the sea—will kick-start the recovery effort.

The ocean—our major life-support system—is endangered. And it cannot be reimagined or redesigned, as it is too vast and complex for us to re-create
from scratch. It must be restored to sustainable levels.

The only reason that our planet is habitable (and a great place to live) is because of the innumerable goods and services that the ocean provides: more than half of the oxygen in the atmosphere, regulation of the climate, carbon sequestration, food security, and huge recreational and commercial opportunities. But in the past century we’ve taken much of this for granted, harvesting from its waters the things we like, especially the large and small animals we love to eat, and throwing in the things we dislike—sewage, garbage, and invisible pollutants such as mercury and PCBs. In addition, because of excessive greenhouse gas emissions, we are changing the very chemistry of the global ocean, warming the seawater and making it more acidic. All of the above results in loss of biodiversity, collapsed species and fisheries, loss of jobs, health issues, and huge economic losses. Just a few years ago, for example, who could have imagined any of the following new realities: 90 percent of the ocean’s large predators, which keep the ecosystem healthy, have been removed by fishing, and scientists predict that all fisheries will have collapsed by 2048. Bluefin tuna and swordfish now have so much mercury in their tissues that women and children are recommended not to consume them. A fifth of the world’s coral reefs have almost no corals left, which means they are home to fewer fish, and our coastlines have less protection. Bacteria reign in coastal areas downstream of agricultural basins, creating oxygen-free dead zones, and jellyfish have become so abundant from overfishing, nutrient pollution, and global warming that they can capsize fishing boats and disable coastal nuclear power stations. Plastics, meanwhile, continue to accumulate in the ocean, killing tens of thousands of marine animals each year.

In just a few generations the rules of the game have changed dramatically—and continue to do so at an unprecedented rate. The consequences are detrimental, and although we can expect more negative ecological “surprises,” we cannot predict what they will be or when they will occur. If current ocean degradation trends continue, will commercial fisheries become extinct? Will the ocean produce less oxygen? Will it be safe to swim at the beach? Will we turn our backs to the ocean if it does not inspire us anymore?

We cannot re-create what the ocean does for us, but we can still keep it from slipping through our fingers. How? By restoring the ocean to a state in which it can deliver an optimum provision of ecosystem services. Already we know that good fisheries management, market-based strategies, and marine reserves have beneficial consequences for the ocean ecosystem, and for the communities and the economies that depend on it. What we need now is a global policy to value and restore ocean ecosystem services, with clear global targets. It took more than 10 years for the Intergovernmental Panel on Climate Change (IPCC) to agree on global emission-reduction targets. Do we know enough to set global ocean-restoration targets?

Since the first scientific ocean expeditions in the 18th century, we have learned much about the ocean, but there is much we don’t know. Only 5 percent of the ocean floor has been studied “at some depth,” and most marine science has been conducted in the shallows. The Census of Marine Life, a 10-year international scientific collaboration, is conducting the first-ever global marine census, creating baselines for comparison by future generations. The results of this ambitious cataloging of marine life, an effort involving more than 2,000 scientists in 80 nations, were published in October 2010. Census scientists have provided further evidence that the ocean is globally interconnected. The fact that marine-life “hot spots” and migratory corridors span many regions makes decisions about how to protect these areas an international concern.

Scientists have been surprised to find a deep ocean unexpectedly rich with complex life and different habitats, with few areas devoid of life. They’ve also found that, in large areas of the seafloor, chemosynthesis may be as important to life as photosynthesis is elsewhere. In every place that Census scientists have explored over the past decade, they have discovered life previously unknown to science. Using sources as diverse as ship logs and monastery records, they have also cataloged historical fish populations; their abundance in the past demonstrates just how much has been lost.

Despite these advances in knowledge, we still do not know how many species are in the ocean. Current estimates range between 178,000 and 10 million—a fudge factor of two orders of magnitude. We know even less about what species do and how they interact with one another. Knowing more about these processes will give us greater understanding of how the entire ecosystem functions. But we cannot wait to obtain all the scientific information to understand all mechanisms. We know enough to understand that ocean biodiversity is in great decline worldwide, and that this decline is diminishing the ability of the ecosystem to provide key services. So what are the next steps?

First, we need to conduct a global Ocean Ecosystem Assessment. It is imperative that we quantify and value the ecosystem services provided by the ocean. This baseline will allow us to forecast the economic losses and social conflicts under different exploitation scenarios. The UN-sponsored “Regular Global Marine Assessment Process,” which published its first report last year, provides an initial global look at the health of the ocean, as a first step toward the establishment of a permanent assessment process. However, this effort does not include a rigorous evaluation of ecosystem services or scenarios under different exploitation regimes.

Second, we need to set restoration targets for ocean ecosystem services. To date, major ocean-management actions are focused on maximizing the yield of individual fisheries without taking into account the full costs of exploitation, including reduction of ecosystem services and associated economic losses. We need to undertake a major research effort similar to that of the IPCC to determine the boundaries of ocean resilience: how much we can harvest, traffic, and mine its waters while ensuring that it can self-repair and provide maximum ecosystem services. These targets should be determined in coordination with IPCC targets and incorporate other major environmental issues such as freshwater, food production, and coastal urbanization.

Third, we need to include ecosystem services into economic and political decision making. Political decisions are generally based on metrics, such as GDP, that do not take into account the full costs of economic activities on ecosystem services. This is clearly leading us to global unsustainability.

While we set restoration targets, we need to scale up the solutions that work in order to start reversing the decline. Using new technologies, we can develop aquaculture that is “clean” and not dependent on fishmeal coming from wild fisheries—as is largely the case today. We can rebuild the structure of the ecosystem, through marine reserves and market-based strategies to manage fisheries, so that the ocean becomes more resilient and productive. These and other near-term solutions will relieve stress on the ocean system now while we deal with the larger stressors associated with global change.

We also need to continue studying the ocean. A few centuries ago we could not have imagined what lives in the ocean and what it does for us, and we will undoubtedly be surprised by what lies waiting for us beneath its surface. The ocean’s extreme environments and microbial chemistry could be the key to finding life in other planets and extending human life on our planet, respectively. But the health of our oceans needs to be restored in order for our species to have a future on this planet.

Enric Sala is a National Geographic Fellow and associate professor at Spain’s National Research Council. Kristin Rechberger is vice president for partnerships at the National Geographic Society.

Originally published December 9, 2010

Tags biodiversity ecology global reset policy

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