Whales As Carbon Sinks?

The ocean and coastal ecosystems are important carbon sinks. A carbon sink is a natural or man-made reservoir that uses physical and biological processes to absorb and store carbon from the atmosphere.

Carbon sinks include things like coal, oil, natural gasses, methane hydrate, and limestone. These sinks have held carbon for millennia after lengthy processes and under specific circumstances. On the flip side, using these fossil resources releases the carbon they contain back into the atmosphere, contributing to carbon dioxide (CO2) emissions. The ocean is a key player in the Earth's carbon cycle. 

NASA estimates that the quantity of carbon in the oceans is around 50 times greater than that in the atmosphere and that it exchanges with the atmosphere over a period of several hundred years. The photosynthesis of marine plants produces at least 50% of the oxygen humans breathe. At the moment, 48% of the carbon released into the atmosphere by burning fossil fuels is sequestered in the ocean. 

Additionally, healthy coastal ecosystems reduce the effects of climate change, particularly by absorbing carbon for their development. Mangroves, seagrass beds, and salt marshes are a few examples of important carbon sinks. They grow by capturing carbon in their calcium skeleton, so they store at least ten times more carbon than continental forests. On a global scale, these coastal habitats only cover a small portion of the world. Additionally, coastal urbanization and coastal economic activity weaken these ecosystems. 

So what else is there? You’d be surprised to learn that one whale is equivalent to hundreds of trees when it comes to protecting the environment! According to recent research by marine scientists, whales—particularly great whales such as baleen and sperm whales—play a substantial role in removing carbon dioxide from the atmosphere (Roman et al., 2014). Throughout their long lives, whales accumulate carbon in their bodies. Each great whale sequesters 33 tons of CO2 on average, removing that carbon from the atmosphere for centuries until the whale sinks to the ocean floor after it dies (also known as a whale fall). 

In contrast, a tree may only absorb up to 48 pounds of CO2 annually. About 60% of the annual carbon sequestration (or storage) in the deep oceans is brought about by whale falls. This is more effective than the combined efforts of the carbon-sequestering ecosystems of seagrass and salt marsh as well as "kelp export," in which seaweed transports carbon loads out to the deep ocean. During the millennia of industrial whaling, tens of millions of whales perished. In search of meat, oil, and other things, whaling destroyed somewhere between 66 and 90% of their population. 

Prior to whaling, scientists predicted that whale populations—aside from sperm whales, which forage at higher depths—would have buried up to 1.9 million tonnes of carbon annually. However, whales are also significant because their iron and nitrogen-rich feces encourage the growth of phytoplankton, a type of microscopic marine algae that absorbs about 40% of the CO2 produced worldwide. 

These tiny organisms capture roughly 37 billion metric tons of CO2, which they use to produce at least 50% of the oxygen that goes into our atmosphere. This is estimated to be 70 times the annual CO2 absorption of all the trees in the US Redwood National and State Parks, or 1.70 trillion trees, the equivalent of four Amazon forests. More phytoplankton equals greater carbon sequestration. 

Because the population of the largest great whales is currently a tiny fraction of what it once was, protecting whales could significantly increase carbon capture. Biologists believe that global whale numbers are now less than one fourth of what they once were, sadly, due to decades of industrialized killing.  

The amount of phytoplankton in the seas and the amount of carbon they absorb each year may both increase dramatically if whales are permitted to return to their pre-whaling population of 4 to 5 million, compared to the roughly 1.3 million today. At a minimum, whale activity would result in a 1% increase in phytoplankton productivity, which would result in the annual capture of hundreds of millions of extra tons of CO2, or the equivalent of 2 billion mature trees. 

Even though commercial whaling has drastically decreased, whales still face numerous threats to their lives, such as ship strikes, getting caught in fishing nets, waterborne plastic waste, and noise pollution. Many whale species are not recovering, though some are, albeit slowly. But not all hope is lost! Satellite data is one of the most effective ways to protect whales. 

For instance, the WWF's Protecting Whales and Dolphins Initiative, which includes Oregon State University, the University of California Santa Cruz, and the University of Southampton, has for the first time mapped the "superhighways" through which the marine mammals migrate using satellite data gathered from more than 1,000 tagged whales by 50 research groups over 30 years. For 50 years, WWF has been actively working to protect whales. They contributed to the campaign to outlaw commercial whaling in 1984. 

The WWF lobbies for the International Whaling Commission (IWC) to have strict control over all whaling. The IWC is the organization in charge of controlling whaling and tackling the enormous number of additional risks to whales. Twenty-five years ago, there were no humpback whales traveling through the Salish Sea (between northern Washington and British Columbia near Vancouver), but the year 2021 saw an unprecedented birth boom. 

The Pacific Whale Watch Association reports that researchers detected 21 calves off the shores of Washington and British Columbia, which is a record high for the area and more than twice the number of calves seen in 2020. According to studies, species with protected habitats have a twofold higher chance of recovering than those without. Additionally, over the past ten years, government initiatives to reduce ocean noise pollution have been successful. 

This is proof that we can help save the whales, and the best way to do it is through governmental protection laws and regulations.