a dingy boat is seen from above floating next to a humpback whale
Researchers investigate a humpback whale by boat and drone in the surface waters near the Western Antarctic PeninsulaDuke University Marine Robotics and Remote Sensing under NOAA permit 1 4809 – 03 and ACA permits 2015 – 011 and 2020 – 016
  • Whales are the biggest animals on Earth and their huge bodies play a role in the carbon cycle.
  • They capture carbon in their body as they live and encourage biodiversity with their poop. 
  • They act as carbon vaults by sinking to the bottom of the ocean when they die, scientists said.

Whales naturally help divert carbon away from the atmosphere in life and death, scientists said in a review published Thursday. 

Because they are so large — with the largest whales bigger even than the dinosaurs — the amount of carbon they capture throughout their lifetime is substantial. 

Though it may not be a solution to the climate crisis on its own, their ability to store carbon is another reason to encourage their numbers to rise in the oceans, the scientists said.

The results of their analysis were published in the peer-reviewed journal Trends in Ecology and Evolution.

Whales naturally store carbon by living their life

Whales capture carbon mainly by pooping and dying. The diagram below explains how. 

A diagram shows how whales help capture carbon from the athmosphere. Two types of great whales are shown pooping, feeding local phytoplankton growth, feeding on the plankton or the animals that eat the plankton, then dying and sinking to the ocean floor.
A diagram shows how whales help remove carbon from the atmosphere.Trends in Ecology & Evolution/Pearson

Any animal, big or small, is part of a carbon cycle. Carbon is present in every lifeform on Earth. Animals get carbon by eating plants and animal products, and plants get it from the atmosphere. 

That carbon is either stored in the body until the animal's death or shed as feces. These byproducts are then nibbled on by other animals and plants, putting that carbon back into the food chain. 

When you're as big as a whale, what happens to your body and your poop can have a huge effect.

"Because whales are so large, they have the potential to store vast amounts of carbon," said Heidi Pearson, a study author and biologist from the University of Alaska Southeast, in an interview with Insider. 

Whales weigh up to 150 tons and can live more than 100 years. That's a lot of carbon stored in their body, away from the atmosphere, until they die.

"You can think of whales as like big floating trees in the ocean," Pearson said. 

a humpback whale is seen from above, feeding.
A humpback whale feeds in the Stellwagen Bank National Marine Sanctuary.Elliott Hazen

Eating, pooping, and peeing the ecosystem back to life

What they don't store in their body, the whales poop and pee back into the ocean. 

Previous studies have shown that this is incredibly important for the ecosystem. When whale populations dropped after the widespread whaling of the 1900s, plankton populations counterintuitively plummeted as well.

That is because plankton feeds on whale poop, so the disappearance of even one whale causes a huge deficit in the ocean ecosystem. This is called the whale pump effect.

By encouraging new life, the whales are creating more organisms that can capture carbon away from the atmosphere.

The whales can then feed on these new lifeforms, in huge quantities, locking that carbon in their body for many decades. 

Finally, when they die, the whales' bodies tend to sink all the way down to the bottom of the ocean, where the carbon stays out of the atmosphere.

"It's going to remain out of contact with the atmosphere for hundreds, thousands of years, maybe even longer. And whales do this naturally," Pearson said. 

A humpback whale breaches.
Breaching humpback whale, Cabo San Lucas, Baja California.Getty Images

Not a silver bullet

By encouraging whale numbers to grow, their carbon-locking effect can be amplified. 

"We feel it's worth conserving whales for many reasons. They're important components of healthy ecosystems and they help to promote biodiversity, given that we are also in a biodiversity crisis," Pearson said. 

"This potential climate benefit is just another reason," she said.

Conservation today is less about whaling and more about creating protected areas in the ocean to avoid collisions with ships, keeping the oceans quiet, and avoiding whales getting tangled in fishing gear, Pearson said. 

"Another big thing is climate change. So it kind of goes full circle," she said. 

Pearson warned, however, that she doesn't think it should be seen as a viable solution to the climate crisis on its own.

Advocates of nature-based solutions suggest that by bringing back biodiversity, for instance by planting trees and encouraging re-wilding, a substantial amount of the excess carbon in the atmosphere could be captured in living organisms.

This is true, and this approach has obvious positive knock-on benefits for the environment, but it's not the full story. 

Estimates suggest that nature-based solutions can provide 37% of the climate change mitigation by 2030 that is needed to meet the goal of keeping climate warming below 2 degrees Celsius, according to the World Bank. 

"They're not the silver bullet. Even if we could really get strong conservation measures and recover whale populations to their pre-industrial whaling abundance, that's still not gonna solve the climate crisis," she said. 

"It's gonna be one small piece of everything we need to do," she said. 

Read the original article on Business Insider