Whales are known for being the largest and most intelligent creatures in the ocean. Now, marine biologists have discovered that they also capture tonnes of carbon from the atmosphere, a service with an economic value of US$1 trillion for all the great whales, according to a study published by the International Monetary Fund.

Up until now, protecting great whales has been viewed as a human good. But the International Monetary Fund research points out that protecting whales also has a monetary incentive, as it turns out whales are an important nature-based solution to capturing carbon from human emissions.

“The carbon capture potential of whales is truly startling,” said the report. “Our conservative estimates put the value of the average great whale, based on its various activities, at more than US$2 million, and easily over US$1 trillion for the current stock of great whales.”

Whales accumulate carbon in their bodies during their long lives, some of which stretch to 200 years. When they die, they sink to the bottom of the ocean, taking the carbon with them. According to the study, each great whale sequesters around 33 tonnes of carbon dioxide on average. A tree during the same period only contributes to 3 per cent of the carbon absorption of the whale.

Wherever whales are found, so are phytoplankton. These tiny creatures produce every second breath we take, by contributing to at least 50 per cent of all the oxygen in our atmosphere. They also capture about 37 billion tonnes of carbon dioxide or four Amazon forests’ worth. Whale poop has a multiplier effect on phytoplankton as it contains iron and nitrogen, the elements phytoplankton need to grow; so, the more whales, the more oxygen.

“The findings of the International Monetary Fund report clearly show the amazing connections between some of the smallest and largest examples of life on our planet—and the importance of understanding these complex relationships not only for their intrinsic value but for the vital role nature plays in keeping us alive too,” said Doreen Robinson, wildlife expert at the UN Environment Programme.

Whale populations are today a smidgen of what they once were. Biologists estimate that there are slightly more than 1.3 million whales in the ocean, a quarter of their pre-whaling number of 4 to 5 million. Some species in particular, like the blue whale, are only 3 per cent of what they used to be. To preserve and protect whale populations, we must reduce the many dangers to whales in our seas.

One way to do so would be to apply the UN-REDD Programme model for protecting forests. Recognizing that deforestation accounts for 17 per cent of carbon emissions, the UN-REDD Programme gives incentives to countries to preserve their forests as a way of keeping carbon dioxide out of the atmosphere.

“In a similar way, we can create financial mechanisms to promote the restoration of the world’s whale populations,” said the report’s authors. “Incentives in the form of subsidies or other compensation could help those who incur significant costs as a result of whale protection. For example, shipping companies could be compensated for the cost of altered shipping routes to reduce the risk of collisions.”

With the Paris Agreement coming into force next year and the effects of climate change ever more prevalent, we must prevent or reverse the harm to global whale populations now. Researchers estimate that unless new methods are put forward, it would take over 30 years to double the number of current whales, and several generations to return them to their pre-whaling numbers. “Society and our own survival can’t afford to wait this long,” they said.