[INFORMATIVE] Swimming Trees: Can Whales Solve Climate Change?

Swimming Trees: Can Whales Solve Climate Change?

By: Sidharth Sanegepelli

It would be an understatement to say that the world’s entire climate crisis is due to carbon. The combustion of fossil fuels leeches carbon dioxide into the atmosphere, which traps heat and prevents it from leaving the Earth. Since it began, scientists have been looking for technological ways to reverse the effects of global warming, whether that be forms of renewable energy or carbon sequestration. Some are even bioengineering forms of plant life to take in more carbon dioxide than normal. However, it is possible that the answer may have been in front of us this whole time—and 2 miles below.

The blue whale—and other mammals in the infraorder Cetacea—may be the largest animals to ever live. Blue whales are nearly a hundred feet long and over 200 tons. Including all four subspecies worldwide, there are somewhere between 10,000 and 25,000 blue whales in the oceans. This is a decimated population, following years of whaling for oil, meat, and their bones. Now, their populations are endangered but stable.

Due to its size, the world’s oceans capture about a third of all carbon dioxide emissions. This is known as blue carbon and is stored in three different ways. One, marine autotrophs such as marine plants, algae, and phytoplankton absorb carbon dioxide from the water and use it to generate oxygen. Two, carbon is sedimented underwater and slowly becomes part of calcium carbonate deposits. Three, and the most important method for today, is carbon being stored in living organisms.

Whales are a large part of the oceans’ carbon sequestration. It begins with the “whale pump,” in which whales simply eat. A blue whale eats around ten to twenty tons of krill a day, which leads to its urine and feces being extremely rich in nutrients. When they expel this waste, it fertilizes phytoplankton blooms that lead to them capturing even more carbon dioxide from the atmosphere. This contributes heavily to the 30–50 billion metric tons of carbon dioxide that the world’s population of phytoplankton absorbs every year. For context, the Amazon Rainforest only fixes around 340 million metric tons of carbon dioxide per year.

While the whale pump is a constant cycle, the biomass storage of blue whales happens from conception to death. On average, a blue whale can store the equivalent of 62 tons of carbon dioxide over the course of its lifetime. To compare this to other organisms, a live oak tree captures only 12 tons of carbon dioxide over its 500-year lifespan. If we estimate a population of 17,500 blue whales, that means through biomass alone, the world’s population of blue whales can store 1.05 million tons of carbon in their lives.

Lastly, when whales die, they create phenomena known as “whale falls.” This is when their carcasses sink to the ocean floor, which traps the carbon in their bodies at the bottom of the ocean. This carbon can go two places: back into the marine ecosystem due to detritivores feeding on the carcass, or into the ocean floor, where the carbon undergoes sedimentation. In both scenarios, the carbon is prevented from reentering the atmosphere.

So far, everything we’ve explored has been cold hard facts. But now, we enter the realm of speculation. What would happen if the world’s population of blue whales doubled?

The first effect that we would see is the most useful one—a decrease of carbon dioxide in the atmosphere. With the increased number of phytoplankton soaking up even more carbon, plus double the carbon stored in whales, plus double the sedimentation of whale falls, it is possible that doubling the whale population would have drastically positive effects on the climate crisis. This, in turn, would lead to ocean temperatures dropping again, which moves that factor back into the range of tolerance for most aquatic species. Additionally, increased populations of phytoplankton would allow the marine food web to be injected with much more biomass and energy from the sun, indirectly making all marine populations’ levels more stable. Whale falls would also have the same effect, making a usually rare source of food much more common for sea life. While not every ecological effect that an increase in whale populations affects can be predicted, it is clear that the pros would far outweigh any cons.

Economic effects from an increase in whale populations are also clear. Whale watching generates around 2.1 billion dollars annually and employs about 13,000 workers. Doubling whale populations would not only have ecological benefits but economic ones as well. Due to the currently sparse population of whales, many people choose not to go whale watching due to the large chance they may not even see a whale. A doubling of the whale population is likely to not only double the number of whale watchers annually, meaning that much more than 2 billion dollars a year could be made off of whale watching.

Despite these benefits, some negative effects of increasing whale populations could be predicted. Whales already interact with the fishing industry in a negative way. For example, sperm whales in the Northern Pacific have adapted to steal fish from baited hooks, taking away from fish’s daily stocks. Additionally, the previously mentioned projected increase in whale watching could affect whale migratory and breeding habits, as improper whale-watching techniques have been shown to make individual whales stressed and anxious. However, likely, these will not be a problem as long as proper fishing and whale-watching policies are implemented and enforced.

So how exactly can we help increase whale populations? For one, we can advocate to protect habitats and create marine protected areas. Allowing whales to reproduce safely is the most natural and effective way to replenish their numbers. Currently, the NOAA has created a recovery plan to promote the recovery of blue whales to the point where they are no longer endangered, and as individuals, spreading awareness for this plan is one of the best ways you can support it. Whales as a species have been around for nearly 50 million years. Appearing well before the first humans, whales are some of the closest links we have to the Earth’s past. They were swimming in our oceans long before us and will likely continue to long after, but only if we help them. If we do, the mutualistic relationship between us and these living giants will continue to benefit us—both of us—for years to come.


Works Cited
NOAA Fisheries. Whales and Carbon Sequestration: Can Whales Store Carbon? NOAA Fisheries, 02-12-24, Accessed 09-28-24, https://www.fisheries.noaa.gov/feature-story/whales-and-carbon-sequestration-can-whales-store-carbon

Ralph Chami, Thomas Cosimano, Connel Filllenkamp, Sena Oztosun. Nature’s Solution to Climate Change. International Monetary Fund, 12-19, Accessed 09-28-24, https://www.imf.org/en/Publications/fandd/issues/2019/12/natures-solution-to-climate-change-chami

Elizabeth Shadwich, Tyler Rohr, Anthony Richardson. Oceans absorb 30% of our emissions, driven by a huge carbon pump. Tiny marine animals are key to working out its climate impacts. CSIRO, 06-13-23, Accessed 09-28-24, https://www.csiro.au/en/news/all/articles/2023/june/oceans-absorb-emissions

International Whaling Commission. The Benefits and Impacts of Whale Watching. International Whaling Commission, 2024, Accessed 09-28-24, https://wwhandbook.iwc.int/en/responsible-management/benefits-and-impacts-of-whale-watching

NOAA Fisheries. Recovery Plan for the Blue Whale (Balaenoptera musculus). NOAA Fisheries, 10-09-20, Accessed 09-28-24, https://www.fisheries.noaa.gov/resource/document/recovery-plan-blue-whale-balaenoptera-musculus-0