By Sofia Pluciennik
Did you know that whales play a surprisingly big role in keeping our planet healthy? Whales have the amazing ability to absorb and store massive amounts of CO2 in their tissues throughout their lives! But here’s the twist — even though they help fight climate change, they’re also among its biggest victims. Warming oceans and changing ecosystems are making it harder for whale populations to recover, and some species could even disappear completely by the end of the century.
How Climate Change and Human Activity Are Threatening Whale Survival
Since the Industrial Revolution, the amount of CO₂ in the air has shot up, affecting life all over the planet. The ocean has been serving as a buffer, soaking up a lot of that extra carbon. If it wasn’t for that, the planet would already be a lot hotter. However, the consequences of that for ocean species, from micro-organisms to whales have been gigantic. This matters because healthy oceans are vital for a healthy planet — they regulate our climate and provide more than 65% of the world’s ecosystem services.
In the past century, the whaling industry almost led whales to extinction. Sadly, to this day, whales are still threatened by human activities such as ship strikes, fishing net entanglements/bycatch, and pollution. Many species are still trying to bounce back from whaling times, but human driven climate change is making it much harder to recover. A study done in 2019 found that if carbon emissions keep rising, fin whale numbers might only reach 5% of what they were before whaling by the year 2100.
How Ocean Warming Is Changing Whale Migration and Habitat Patterns
Another direct impact of ocean warming predicted and observed is the change in species distributions and migration patterns. Many species will have their habitats reduced and/or need to migrate to different regions. One example is the Pilot whale population, which has been observed migrating towards the poles at strikingly high rates, even though those are not the areas of bigger prey concentration, indicating a direct response to warming waters. With increasing whale populations shifting polewards, those areas end up with a lot more competition for natural resources (such as food) than usual. In addition, observations have already shown shifts in migration timing as waters warm and cool at different times than they used to. For instance, during the 2018–2019 winter, a group of bowhead whales that typically migrate south to the Bering Sea remained in the colder waters of the Beaufort Sea and Amundsen Gulf, skipping their migration entirely.
Another effect worth knowing is that increasing sea temperatures can have physiological impacts and affect sea mammals’ metabolism and overall health. This can occur due to increased stress and abnormal body temperatures that result in increased metabolic rates and, consequently, energy expenses, malnutrition and more susceptibility to diseases.
How Declining Krill Populations Threaten Whale Survival and Reproduction
A further big problem is the decline in krill populations — tiny shrimp-like creatures that are the main food for many whale species, like our loved humpbacks. Krill rely on sea ice for part of their life cycle, but as the ice melts, their numbers are dropping fast. In the Scotia Sea, krill populations have fallen by 30% since the 1980s, and models predict drops of more than 85% in some parts of the world.
When there’s not enough food, whales struggle to migrate, reproduce, and survive. Some species that feed in mid-latitude areas, like humpbacks and fin whales, are especially at risk. In southern Brazil, scientists found that krill numbers are closely tied to whale birth rates — fewer krill means fewer whale calves. Poor nutrition can lead to miscarriages, stunted growth in unborn calves, and even delayed maturity in females. In Hawaii, the number of humpback whale mothers with calves dropped by over 75% between 2013 and 2018 — a change linked to climate shifts. During that same period, nearly 40% of pregnancies failed.
How Whales Fight Climate Change: The Whale Pump, Carbon Storage & Ocean Health
Despite all of these sad circumstances, whales are still managing to help us a lot in ways most people don’t even realise! Their poop (yep, really) and pee are full of nutrients. When they excrete, they help spread that nutrient across their long migrations and help keep nutrients at the surface. This is what we call the “whale pump”, and the result is helping tiny ocean organisms called phytoplankton grow. Phytoplankton are a major part of the food chain — and they also suck up a lot of CO₂ through photosynthesis. Whales are especially important because they eat krill, which is full of iron, and iron is a key nutrient for phytoplankton growth.
Phytoplankton also produce over half of the oxygen we breathe, so whales actually help keep our air clean and breathable. Whales are also capable of storing carbon in their massive bodies. The bigger and older they are, the more carbon they hold. When they die, their bodies sink to the ocean floor, locking away carbon for thousands of years. Before commercial whaling, five southern whale species stored around 400,000 tonnes of carbon every year. By 1972, that had dropped to just 60,000 tonnes. If whale populations recover, they could store up to 170,000 tonnes a year by 2100 — or even more if we tackle climate change together.
To sum up, whales help fight climate change in powerful ways — from absorbing carbon to supporting life in the ocean. They also benefit people directly through eco-tourism, such as whale watching, and hold cultural and educational value for communities around the world. Protecting whales means protecting our future. We must act now to reduce emissions and protect the oceans, but we are not alone; we at least know we have whales on our side in the fight against climate change! If we help whales survive, they’ll help us do the same.
Come hang out with the beautiful humpback and us if you want to know more about their abilities and struggles and what you can do to help them!
References:
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