Take a Breath, Thank a Whale

By Regina Asmutis-Silvia and Sulmaan Wasif Khan, Foreign Policy

21 August 21

Like the Amazon rainforest, the planet’s whales play crucial roles as carbon captors. That’s just one reason to save them.

very spring, the Massachusetts and Cape Cod bays see some of the world’s finest carbon captors in action. North Atlantic right whales, bound for Canada or other summer habitats, come by, gorging on crustaceans known as copepods. Humpbacks, meanwhile, stay through the fall as they indulge on small fish: sand lance, menhaden, and herring. Thus nourished, the whales pack carbon in their massive bodies. And their waste fertilizes minute organisms called phytoplankton, which form a free-floating ocean forest in the sunlit surface waters. Phytoplankton, like terrestrial plants, conduct photosynthesis, releasing oxygen to the atmosphere and removing carbon dioxide. Take a breath, thank a tree, as the saying goes; take another breath and thank the ocean and the whales who tend its garden.

Of course, other marine animals contribute to the carbon cycle in similar fashion, but the whales’ size allows them to do so at unparalleled scale and efficiency. Even in death, their job as environmental engineers is not done. When they sink to the seabed as a “whale fall,” they take enormous amounts of carbon with them and give life to deep-sea organisms for decades. In the battle against climate change, whales are on the front lines. All of which makes the utterly preventable deaths of as many as 28 right whales and 77 humpbacks since 2017 not just tragic, but dangerous.

Policymakers are coming around to the idea that climate change is an existential threat, whether it’s creating droughts that trigger waves of migrants or causing waters to rise and eventually drown whole cities. Within the United States, addressing climate change is one of the rare points on which people across the political aisle are moving closer to one another, particularly younger voters. In 2019, the director of national intelligence’s statement of the Worldwide Threat Assessment noted that environmental degradation and climate change would probably “fuel competition for resources, economic distress, and social discontent through 2019 and beyond.”

That assessment is shared globally. The World Economic Forum’s 2019 Global Risks Report listed extreme weather events and failure of climate change mitigation and adaptation as the two most likely risks. They were also the second and third highest-ranked risks in terms of impact. The 2016 Paris agreement on climate change (from which the United States withdrew a year later) marked a worldwide recognition that something had to be done about the danger. The search for that something has focused on renewable energy and, to a lesser extent, on reforestation. But the role of whales in carbon sequestration, although known to biologists for a while now, has yet to gain the attention it merits among policymakers.

There are three good reasons for policymakers to change course.

First, the quest to limit global warming needs to proceed along all possible avenues. Divestment from fossil fuels and reforestation are indubitably important, but such efforts need reinforcement from healthy marine ecosystems pumping carbon out of the atmosphere. Just how effective an individual whale can be is hard to calculate—it depends on diet, longevity, habitat, and other ecological factors—but Andrew Pershing of the University of Maine and his colleagues have demonstrated that restoring populations of large whale species to pre-whaling levels (working with conservative estimates of what those levels were) would store carbon “equivalent to 110,000 hectares of forest or an area the size of the Rocky Mountain National Park.” In addition, he and his co-authors calculate that whale falls would bury carbon “equivalent to preserving 843 hectares of forest each year.” Those figures do not even account for the massive impact whales have by fertilizing the phytoplankton whose photosynthesis provides us with an estimated 70 percent of our oxygen and absorbs at least 30 percent of atmospheric carbon dioxide.

The second reason to focus on whales is that preventing whale deaths is not impossible. The required fixes—modifications to fishing and slowing down ships—are feasible if the world chooses to work toward them. For example, a seasonal speed restriction of 10 knots on certain ships implemented in 2008 along the east coast of the United States reduced ship strike mortality risk to endangered North Atlantic right whales by 80 to 90 percent. The U.S. National Marine Fisheries Service determined that a seasonal fishing closure in Massachusetts waters reduced entanglement risk to right whales there by at least 24 percent. However, such regulatory measures come with economic consequences and are therefore generally opposed by industries that must absorb those impacts, regardless of the ecological benefit they may create.

Finally, climate change is not a threat that we can address in one fell swoop and then move comfortably on from; it will require constant work. Limiting global warming and then keeping it limited is a task that will go well beyond 2100. It will rely on the oceans contributing to the carbon cycle as they have for so long—and, for that, letting whales thrive will be crucial.