Sea Otters v. Climate Change

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When people talk about sea otters, the words “cute,” “cuddly,” and “curious” often come to mind. But now you can add another descriptor to that list -- climate change fighters.

Along the West Coast these aquatic acrobats have become a surprising vanguard in the fight to strike at the root cause of climate change trends. And their heartwarming tale illustrates a much larger story about the ways wildlife conservation can also combat climate change.

Kelp is an efficient absorber of CO2. Photo courtesy of NOAA's National Ocean Service.

Here’s how otters do it.

Climate change is the result of a buildup of heat-trapping gases in our atmosphere. One of the most significant contributors to this phenomenon is carbon dioxide (CO2), a gas emitted by coal-burning power plants and automobiles, among other things.


Kelp forests, where otters hang out, are some of the most efficient absorbers of carbon dioxide known. Like any land-based forest, kelp forests sequester carbon dioxide from the atmosphere through photosynthesis, transforming it into the energy they need to build their leafy structure.

But these kelp forests are at risk from sea urchins: small, spiky marine animals that love munching on kelp. With no predators around, sea urchin populations can multiply, forming herds that sweep across the ocean floor devouring entire stands of kelp.

Fortunately, sea otters have an appetite for urchins. The otters help keep urchin populations in check, allowing kelp to flourish and capture more CO2. According to a recent study, otter-supported kelp forests can absorb up to 12 times more CO2 from the atmosphere than if they were just left to the urchins.

Urchins along the seafloor. Photo courtesy of tinatinatinatinatina.

For a time, otters were not around to eat urchins. Sea otters were nearly hunted to extinction during the fur trade in the 18th and 19th centuries. But through conservation efforts, sea otters have been restored to much of their historic range in North America.

Sea otters play a small role in mitigating global climate change, but their impact points to a larger lesson: wildlife conservation can save vegetation needed to reduce CO2. Whether it is pumas, jaguars, and eagles in the forests of Venezuela that keep understory browsers in check, grey wolves keeping willow-munching elk on their toes in Yellowstone National Park, or otters guarding kelp along the coast, these non-human neighbors can foster plant growth that leads to more carbon capture.

And with sea otters, the effort to mitigate climate change through top predators has never been so adorable.