Whales have an important but overlooked role in fighting the climate crisis, researchers say


The world’s largest whales are more than amazing creatures. Like the ocean, soil and forests, whales can help save humanity from the accelerating climate crisis by sequestering and storing planet-warming carbon emissions, researchers say.

In a paper published Thursday in the journal Trends in Ecology & Evolution, climate researchers suggest that whales are important but often overlooked carbon sinks. The enormous size of these marine mammals, which can reach 150 tonnes, means that they can store carbon much more effectively than smaller animals.

And because whales live longer than most animals, some for more than 100 years, the paper said they could be “one of the largest stable living carbon stores” in the ocean. Even when dead, whale carcasses descend into the deepest parts of the sea and settle on the seafloor, trapping the carbon they have stored in their robust, protein-rich bodies.

One indirect way that whales can be critical carbon sinks is through their feces. Whale poop is rich in nutrients that can be absorbed by phytoplankton, tiny organisms that absorb carbon dioxide as they grow. When they die, the phytoplankton also sink to the bottom of the seafloor, absorbing tiny bits of carbon in their carcasses.

The carbon sequestration process helps mitigate climate change, because it locks up carbon that would otherwise have warmed the planet elsewhere for hundreds, if not thousands of years.

However, whales are threatened, with six of the 13 great whale species classified as endangered or vulnerable due to threats including industrial whaling, which has reduced whale biomass by 81%, as well as entanglement. with fishing gear, climate change induced changes in prey availability. , noise pollution and more.

Heidi Pearson, lead author and a researcher at the University of Alaska Southeast, said the research shows that protecting whales has a double benefit: helping to stop the biodiversity crisis and human-caused climate change.

The document brings together all the available research on how whales function as critical carbon sinks. As the need for nature-based solutions grows, like planting trees to help solve the climate crisis, Pearson said it’s important to understand whales’ ability to sequester carbon.

“You can think of protecting the whales as a low-risk, low-regret strategy, because there really are no downsides,” Pearson told CNN. “What if we protect them and get ecosystem benefits in addition to carbon?” He said this strategy is risk-free compared to other expensive and unproven solutions to capture and trap carbon, such as geoengineering. There has been a lot of research and analysis on the contribution of whales to carbon storage over the years.

In 2019, economists at the International Monetary Fund attempted to quantify the economic benefits of whales. The first analysis of its kind looked at the market price of carbon dioxide, then calculated the total monetary value of the whale based on how much carbon it sequesters, plus other economic benefits such as ecotourism. He put the average value of a great whale at $2 million.

But large knowledge gaps remain to fully determine how whale carbon should be used in climate mitigation policies. Asha de Vos, a marine biologist and founder of Oceanswell in Sri Lanka, said it’s important to recognize that whales have “more to offer than their beauty and charisma,” and that protecting them is key to a well-functioning ocean ecosystem.

“But, as the authors suggest, we shouldn’t overemphasize the role of whales in these spaces as we don’t have enough research,” de Vos, who is not involved in the study, told CNN. “Fundamentally, the whales will not save our oceans or the planet on their own, but they will likely play a role in the larger system.”

As Pearson continues to investigate carbon from whales in Alaska, particularly delving into the indirect pathways in which whales may be carbon sinks, he said he hopes the current document will prompt lawmakers to consider whales an important part of climate mitigation strategies.

It’s another layer linking the biodiversity crisis to the climate crisis, but for now, Pearson said she and a team will be back in the field to fully quantify the carbon impact of whales.

“Whales are not a panacea to save the planet; it’s just one small thing we could do among many other things we need to do about climate change,” Pearson said. “We just need to clear up the scientific story.”