Predicting human survival on Earth requires oceans

When scientists consider “planetary boundaries,” which describe the conditions within which humanity can continue to thrive, they tend to disregard oceans. And that’s a big problem, a new paper argues.

The oceans are an integral part of life on Earth. They cover two-thirds of the planet and supply half of our air. They absorb vast amounts of heat produced by climate change and provide enormous value in the form of natural goods and services essential to life, including carbon sequestration and food.

First introduced in 2009 and now incorporated into the United Nation’s Sustainable Development Goals, the planetary boundaries framework defines limits for nine planetary processes, including climate change and the freshwater cycle.

The new paper in Nature Ecology and Evolution¬†calls the near absence of oceans from planetary boundaries a major oversight that limits the understanding of Earth’s actual boundaries and the framework’s usefulness for policy considerations.

“Ignoring the oceans is like taking your car in for a tune up and only checking the tire pressure.”

“Oceans are a fundamental part of the processes of our planet,” says coauthor Benjamin Halpern, a professor of environmental science and management at the University of California, Santa Barbara.

“To talk about planetary boundaries, you have to include the ocean. If you were to flip it around and define planetary boundaries based only on the oceans, wouldn’t it seem odd to exclude the land? Ignoring the oceans is like taking your car in for a tune up and only checking the tire pressure.”

Including oceans in the planetary boundary framework could entail accounting for changes to marine habitats, such as mangroves, in analyses of land-system changes and including the demands of seafood production on freshwater supplies.

Halpern says the paper provides a heuristic framework for thinking about how humans interact with the planet, but more research is needed to delineate where the planetary boundaries lie.

Source: UC Santa Barbara