How Do Whales Change Climate

A healthy ocean equals a healthy planet and whales have an important role to play in all of this. They help phytoplankton to thrive and in doing so, they increase the oceans ability to capture carbon. Not only this, but whales are also living carbon stores themselves.

Whales can influence the environment in many different ways; as consumers, prey and even carbon stores. The presence of a whale has a knock-on-effect on the wider ecosystem, making it crucial to protect them for the health of the planet and to mitigate climate change. Before diving into their role in combating the climate crisis, we must first understand phytoplankton and its relationship with whales.

Phytoplankton are small plant-like organisms that play a key role in marine ecosystems. Through photosynthesis, phytoplankton produces up to 50% of the world’s oxygen. It also captures 37 billion metric tonnes of carbon from the atmosphere every single year, which is equivalent to 40% of all carbon produced on the planet and four times more than what the Amazon rainforest captures.

Whales help phytoplankton to thrive, which in turn, increases the ocean’s ability to capture carbon. They do this by two ways: through their swimming and feeding patterns, and through defecation. When whales dive down to the deep sea to feed and later re-surface, they bring up deep water nutrients. This motion is so important as it helps circulate essential nutrients throughout the ocean, particularly to the surface where they are more scarce. All these nutrients are vital food for phytoplankton. Whale defecation is another way in which the species help phytoplankton flourish; whale faeces contain nitrogen and iron, which fertilises phytoplankton, allowing it to bloom and grow.

As well as helping phytoplankton to persist, whales are actually living carbon stores themselves. This is what’s known as blue carbon. Whales are able to store carbon in their bodies, and they do this throughout their lifetime and even after they die. When a whale perishes, its body sinks to the bottom of the ocean, taking carbon along with it. This carbon stays locked in the bottom of the ocean and is unlikely to re-emerge for a millenia. A study in 2010 suggested that the eight types of baleen whales carry about 30,000 tonnes of carbon to the bottom of the ocean each year. However, if whale populations returned to their former size, this carbon sink would increase to 160,000 tonnes each year.

Whales are important regulators of carbon levels in our atmosphere and they are living examples of the effectiveness of nature-based solutions against climate change. If we allow whale populations to recover, we are increasing the ocean’s ability to capture and store carbon by a significant amount.

The Threats That Whales Face
Whales face a large number of threats today and many species are increasingly at risk of extinction. Here are some of those threats listed below:

Climate Change

The climate is changing extremely fast, which means species don’t have time to adapt. Changes in ocean temperature, decline in food sources, loss of habitat, acidification and freshening of seawater are just some of the ways in which climate change is threatening the future of whales. It is affecting the marine mammals’ migration, distribution, and even their ability to reproduce. Furthermore, a loss in food sources is increasing the competition of prey species.

Noise pollution

Over the past few decades, noise pollution in the marine environment has increased dramatically. Man-made noise is not only disturbing the natural marine environment but it is also drowning out the noise of marine wildlife. Sound is the most important sensory signal for marine animals as it allows them to communicate and gather information from extremely far distances. They rely on sound to locate prey, communicate, avoid predators and also sense their surroundings. However, human-generated noise is disrupting their natural behaviour, physiology and chances of reproduction, which can consequently lead to an increased risk of mortality.

Chemical pollution

A number of studies on whale tissue have revealed significant levels of persistent organic pollutants (POPs) and endocrine disrupting chemicals (EDCs). High levels of these chemicals are able to damage the immune system of whales as well as their ability to reproduce.


It is estimated that more than 8 million tonnes of plastic enters the ocean each year. When marine animals ingest plastic, it fills up their stomach and reduces the feeling of hunger, which often leads to starvation. As plastic such as fishing gear is often discarded in ocean waters, it can entangle any animal that swims in its way. This can restrict the animals movement and make it difficult for them to feed or swim. Animals can also suffer infections or physical trauma from this.


People have been whaling for thousands of years. When industrial whaling began in the 1930s, as much as 50,000 whales were being killed annually. In 1986, commercial whaling was officially banned under the International Whaling Commission (IWC)’s moratorium. Although some countries including Norway, Iceland and Japan still practice whaling, this ban on commercial whaling has allowed certain populations to recover. However, the scale at which it occurred in the past and the slow rate at which whales breed has meant that some species are still struggling to increase their numbers.

Whales have the ability to store a large amount of carbon but this has been reduced by an estimated 9 million tonnes by commercial whaling. Therefore, whaling has played a big part in accelerating the effects of climate change by decreasing the number of whales that can lock carbon back in the oceans.

Conservation Measures
For many people, it’s easy to ignore what’s happening beneath the waves. However, the health of the ocean is intrinsically linked to the health of our planet, and whales play an important role in all of this.

More whales in the ocean means less carbon dioxide in the atmosphere and a healthier ocean. Whales reproduce very slowly so protecting them is extremely important as it takes a long time for populations to grow. By identifying areas where whales are vulnerable and studying their habitats, conservation organisations are able to protect these places by changing the way we use them. This includes shipping, fishing, noise pollution, marine litter and more.

What We Can Do
Conservation of the world’s biodiversity is critical in tackling the climate crisis and this is a prime example of why. Nature already has all the solutions we need to combat climate change; we just need more people in power advocating for it.

And we still have time, albeit limited. Often when an issue comes into the forefront of the public eye, action is more likely to be taken by governments and policymakers. Some of the ways we can help make this happen is to educate others on the importance of whales and support whale conservation organisations that are already doing all the groundwork. We can also make changes in our individual lives; it could be anything from reducing our plastic use, cutting fish out of our diet, or even being more aware of the chemicals we flush down our drains. Everyone has a part to play in the climate crisis no matter how small – collective action is key.

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