Why whales are climate change heroes

Let’s be honest – whales are awesome. As the biggest animals in the ocean, they need space to feed, breed and thrive. But only recently have we realised just how much our oceans also need whales, especially in the face of climate change.

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What makes whales so important? It’s actually a number of reasons. Undoubtedly these are amazing animals in their own right, with complex social structures, and even their own types of culture. And many of the ways that whales amaze us are the very reasons they help keep oceans healthy.

Whales live a long time

Species like blue whales can easily live to more than 100 years old, and scientists believe that the Arctic bowhead whale can live much, much longer – at least 250 years. They are living carbon stores, taking carbon into their bodies when they feed and locking it away for their whole lives.

Whales eat and breathe

Because they breathe air, whales need to visit the surface regularly, but they feed in the water itself. Different whales eat different things. Some sift huge quantities of plankton and krill from the surface waters, and others dive thousands of metres to hunt squid in the inky depths. That means they mix nutrients vertically in the ocean too, connecting the sunlit surface with the silent deep.

Whales poop

Shit does indeed happen. Simplistic as it sounds, poo is a great fertiliser. By mixing and redistributing nutrients, whales make the ocean more fertile for tiny microscopic plants called phytoplankton. These miniscule plants catch carbon from the atmosphere through photosynthesis, storing it in their own cells instead. In the process, the produce more than half of the oxygen on the planet. As if that wasn’t enough, these tiny floating marvels are the basis of all ocean food chains, including the whales’ own food.

Whales move around the ocean a lot

They travel between feeding and breeding grounds, often covering many thousands of miles in massive migrations. That means they link up distant parts of the globe. A whale born in warm, tropical seas might feed in the freezing waters of the Southern Ocean. So they play an important role in spreading nutrients across vast distances: by moving between the surface and the deep, and spreading their poo across the oceans.

Whales die

After a hopefully long healthy fun life, whales die. Given that they travel massive distances, a whale’s dead body could end up far away from where it was born or went to feed. When they sink to the seafloor, so-called ‘whale falls’ become a whole ecosystem in themselves, supporting all sorts of weird and wondrous deep sea creatures, from worms to sharks. Crucially, they also take a whole bunch of carbon down to the sea floor with them.

 

All of this means that whales are climate heroes. Capturing and storing carbon, mixing nutrients, keeping the ocean healthy, and making it able to deal as best as it can with the climate crisis. They’re not alone either. Scientists are now discovering just how crucial sea life is for all of us, from the carbon stored in sea plants to all sorts of animals.

Whales are special though. Their massive size, movements and migrations means they’re effectively ecosystem engineers – they fundamentally alter whole habitats, making them more hospitable for other species. So as they’re quietly going about their lives, they are making the ocean – and the planet – a healthier, more resilient place.

What we have done to whales over the past few centuries, by relentlessly hunting many species almost to extinction, has not only been bad for whales, but the whole planet.

Whales are still under threat. Although commercial hunting has largely ended, new threats to whales are challenging remaining populations. These include pollution from plastics and chemicals, rapidly changing habitats, entanglement in fishing equipment, and disturbance from shipping, industries and the military.

We need to give whales the best possible chance to help keep our oceans healthy for all our sakes.

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