Understanding Our Planetary Boundaries Means Accounting for Oceans Too

The idea of Planetary Boundaries has had remarkable influence on how scientists and policymakers think about the earth’s capacity to support humanity. First introduced in 2009 and now incorporated into the United Nation’s Sustainable Development Goals, the framework defines limits for nine planetary processes that regulate conditions for life, such as climate change and the freshwater cycle, within which humanity can continue to thrive.

Yet, the framework largely ignores something that covers two-thirds of the planet – our oceans. According to a new paper, published October 24th in Nature Ecology and Evolution, the near absence of oceans from the framework, which focuses primarily on land-based systems, is a major oversight that limits our understanding of the planet’s actual boundaries and the framework’s usefulness for policy.

“Oceans are a fundamental part of the processes of our planet. To talk about planetary boundaries, you have to include the ocean,” stated co-author Ben Halpern, executive director of NCEAS. “If you were to flip it around and say define planetary boundaries based only on the oceans, wouldn’t it seem odd to exclude the land?”

Half of the air we breathe comes from oceans. They absorb vast amounts of heat produced by climate change and provide us enormous value in the form of natural goods and services essential to life, such as carbon sequestration and food.

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

According to the study’s authors, including oceans in the planetary boundary framework could entail accounting for changes to marine habitats, like mangroves, in analyses of land-system changes and including the demands of seafood production on freshwater supplies, among other ways.

Halpern explains the paper provides a heuristic framework for thinking about how humans interact with our blue planet. Further research is needed to actually delineate where these planetary boundaries lie.

Watch the paper's video abstract, created by lead author Kirsty Nash of the University of Tasmania, below.