by
Cnn
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The world’s largest whales aren’t just amazing creatures. Just like the ocean, soil and forests, whales can help save humanity from the accelerating climate crisis by sequestering and storing planet-warming carbon emissions, say the researchers.
In an article 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 tons, means 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 says they could be “one of the largest stable living carbon sinks” in the ocean. Even when they die, whale carcasses descend to the deepest parts of the sea and sink to the seabed, trapping the carbon they’ve stored in their robust, protein-rich bodies.
An indirect way that whales may be important carbon absorbers is through their feces. Whale poop is full of nutrients that can be taken up by phytoplankton, tiny organisms that absorb carbon dioxide as they grow. When they die, the phytoplankton also sink to the sea floor, taking tiny bits of carbon into their carcasses.
The carbon sequestration process helps mitigate climate change, because it locks in carbon that would otherwise have warmed the planet elsewhere for hundreds, if not thousands, of years.
Yet whales are under threat, with six out of 13 large whales classified as endangered or vulnerable due to threats including industrial whaling, which has reduced whale biomass by 81%, as well as entanglement with gear fisheries, changes in prey availability induced by climate change, noise pollution and more.
Heidi Pearson, lead author and researcher at the University of Alaska Southeast, said research shows that protecting whales has a double benefit: helping to stem the biodiversity crisis and human-caused climate change.
The paper brings together all available research on how whales function as critical carbon stores. As the need for nature-based solutions like planting trees grows to help solve the climate crisis, Pearson said it’s important to understand whales’ ability to trap carbon.
“You can think of protecting whales as a low-risk, low-regret strategy, because there’s really no downside,” Pearson told CNN. “What if we protect them and get ecosystem benefits other than carbon?” He said there was no risk to this strategy compared to other costly and untested solutions to capture and trap carbon, such as geoengineering. Over the years, much research and analysis has been conducted on the contribution of whales to carbon storage.
In 2019, economists at the International Monetary Fund attempted to quantify the economic benefits of whales. The first-of-its-kind analysis looked at the market price of carbon dioxide, then calculated the whale’s total monetary value based on how much carbon it captures, plus other economic benefits such as ecotourism. He put the average value of a large 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 was 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, whales alone won’t save our oceans or the planet, but they likely play a role in the larger system.”
As Pearson continues to research whale carbon in Alaska, especially delving into indirect pathways in which whales may be carbon sinks, he said he hopes the current paper will prompt policymakers to consider whales as a significant part of the 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 return to the field to fully quantify the carbon impact of whales.
“Whales are not a silver bullet to save the planet; it’s just one small thing we could do among so many other things we need to do about climate change,” Pearson said. “We just need to clarify the scientific story.”
