The contribution of whales to reducing greenhouse gases takes a surprise route, as is often the case in nature: Whale excrement is the preferred food of phytoplankton. These plant micro-organisms suspended in the seas and oceans are major consumers of the minerals in faecal matter, which is rich in iron and nitrogen.
Capturing CO2 by eating whale waste
Phytoplankton make a decisive contribution to the natural equilibrium of our world:
- They produce over half of the planet’s oxygen.
- When the micro-organisms that eat whale waste grow, they capture about 40% of the CO2 in the atmosphere, which totals about 37 billion tonnes of carbon dioxide every year.
- Phytoplankton capture as much CO2 as 1.7 trillion trees, the equivalent of four times the number in the Amazonian forest.
The diet of whales plays as decisive a part as that of phytoplankton in the fight against global warming. These massive aquatic mammals eat enormous amounts of phytoplankton and, as a result, store CO2 their entire lives. The larger the whale, the more carbon it stores.
An adult blue whale eats the equivalent of 424 kg of carbon each year on average. When a whale dies, it sinks and takes the CO2 it stored with it. The average 33 tonnes of CO2 every whale stores remains trapped in the depths for centuries in a phenomenon known as blue carbon sequestration.
One threat: Fishing
This makes the preservation of whales an even more vital cause. However, although commercial whaling has been prohibited for nearly 40 years, subsistence hunting for food and hunting for scientific research are still allowed. Accordingly, the whale population has not recovered.
It is estimated that ocean fisheries have released at least 0.73 billion metric tonnes of CO2 into the atmosphere since 1950. Globally, 43.5% of the blue carbon extracted by fisheries in the high seas comes from areas that would be economically unprofitable without subsidies. Limiting blue carbon extraction by fisheries, particularly in unprofitable areas, would cut CO2 emissions by burning less fuel and reactivating a natural carbon pump as fish stocks rebuild and carcasses’ deadfall increases. 
Another threat: Shipping
Collisions with cargo ships also threaten whales. Nearly 100 whales are killed every year along the west coast of the US. The solution would be to have the ships take different routes. However, this is not easy to do because ship-owners are protective of the maritime routes their vessels use.
Protecting whales is an integral part of the blue economy. We believe it is essential at a time when the need fight greenhouse gases and global warming is greater than ever. As incredible carbon sinks, whales are animals that must be protected at all costs for the well-being of the entire planet.
Investing in the blue economy
As a global sustainability theme, investing in the blue economy is fully aligned with BNP Paribas Asset Management’s sustainable investment priorities. These are focused on the energy transition, environmental protection and equality & inclusive growth.
We believe investing in the blue economy will help advance the fight against climate change and ensure that the oceans can continue to function as a sink for carbon emissions from human activity. Such investments are suited for investors with a long-term perspective, an interest in contributing to a greener future and making a positive impact.
In our view, finance can play a major role in pushing companies linked to the blue economy to improve their practices. Those investors who consider the preservation of marine resources as an absolute priority are set to see investment opportunities in companies that develop marine and ocean projects opening up as awareness of the blue economy’s appeal grows.
 Source: Let more big fish sink: Fisheries prevent blue carbon sequestration—half in unprofitable areas; https://advances.sciencemag.org/content/6/44/eabb4848/tab-figures-data
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Any views expressed here are those of the author as of the date of publication, are based on available information, and are subject to change without notice. Individual portfolio management teams may hold different views and may take different investment decisions for different clients. This document does not constitute investment advice.
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