What makes whales fin-tastic climate champions?

Here's how they can be a nature-based buffer against the climate crisis

humback whale jump

Whales are the largest living creatures on the planet. In fact, blue and fin whales are the two largest animals that have ever existed. But this massive stature is not their only superpower: whales play an important role when it comes to climate change mitigation.

Scientists have discovered in recent years that great whales (baleen whales and sperm whales), can capture significant amounts of planet-heating carbon from the atmosphere.¹ Scientists have estimated that one whale’s ability to capture carbon from the atmosphere is equal to that of thousands of trees.² This is critical as climate change is an existential crisis impacting our planet in startling ways from sea to shore.

Whales also have some of the longest migrations of any mammal on Earth. Along these oceanic journeys, or "blue corridors," whales fertilize the marine ecosystems they move through and support the marine life inhabiting them.

So, could protecting whales be a potential nature-based solution and harbinger of hope not just for ocean ecosystems, but also in the climate fight?

Superpower: Carbon absorption

Throughout their long lives, whales accumulate carbon from the atmosphere in their bodies. Given that some species of whales can live well over 100 years, they have the potential to capture quite a lot of carbon.

When they die, they sink to the ocean floor. And as they settle there, so does the carbon that was stored in their bodies. While for most land animals, carbon is released into the atmosphere after death, at the depths of the ocean floor, it can remain for centuries in a phenomenon known as “blue carbon.” For large marine creatures like whales, it can take up to 1,000 years for the elements from their carcasses to cycle their way back up to the surface.³

The longevity of their lives, coupled with their massive size, makes whales invaluable carbon sinks. Each great whale can sequester up to 33 tons of carbon dioxide from the atmosphere due to their sheer size—even more impressive when compared to the 48 pounds of carbon dioxide the average tree sequesters throughout its lifespan. Another study found that recovering baleen whale populations could have the potential for storing carbon equivalent to the amount in a 272,000 acre-forest—an area the size of Rocky Mountain National Park.4

Superpower: Phytoplankton multiplier

Phytoplankton are microscopic creatures that are mighty carbon sinks in their own right. They capture about 37 billion metric tons of carbon dioxide (that’s an estimated 40% of all CO2 produced!) and produce at least 50% of all oxygen in our atmosphere. This amount of carbon dioxide is equivalent to four times the amount captured by the Amazon rainforest.5

Whales have a multiplying effect on phytoplankton numbers wherever they travel. They do this in a couple of different ways:

  1. The “whale pump”
    As whales swim through the water column, they stir up minerals deep in the ocean and bring them to the surface through this vertical movement. They then spread them across the oceans through their migrations in a process known as the “whale conveyor belt.” These physical activities essentially fertilize the ocean with the nutrients needed to help phytoplankton grow.
  2. Nutrient-rich waste
    Whale excrement contains iron, phosphorus, and nitrogen, which are substances that phytoplankton need to grow. This feeds and nourishes the phytoplankton.

Every hero has a villain

There are around 1.3 million whales today, but this number stands in stark contrast to pre-commercial whaling when around 4 million to 5 million whales traversed the high seas. “While a global ban on commercial whaling has virtually eliminated this threat, whales still face significant threats to their survival,” says Leigh Henry, director of wildlife policy at World Wildlife Fund. “This is largely from entanglement in fishing gear and nets, ship strikes, plastic and noise pollution, and climate change.” Six out of the thirteen great whale species are either endangered or vulnerable.

The big fight

Many solutions for combatting climate change are complex and expensive. Restoring whale populations is just one of many natural ways to boost carbon storage that are needed to help reduce greenhouse gas levels in the atmosphere. And, as a migratory species, whales can exert this superpower across the globe. In order to help whale populations recover, the threats impacting their survival must be addressed.

There is growing evidence that whales play a role in the carbon cycle, and there is so much more to discover. But one thing is for sure, whales are key members of the team in the fight to save humanity from the climate crisis. However, they can’t save our planet on their own. They, along with many other valiant marine species, play vital roles in the larger web of life that allows our ocean to thrive, and they need us on the same team, now more than ever.