Whales could save the planet. A report from the International Monetary Fund reveals that great whales - such as humpbacks, blue, grey, right, fin, sperm and bowhead - play a crucial role in extracting CO2 from our warming planet. In fact, one whale is worth more than a thousand trees.
Each of these giants builds up large amounts of carbon in their bodies which on their death sink to the bottom of the ocean taking an average of 33 tonnes of CO2 out of the atmosphere for centuries. Also, whales play an important, and as yet not fully understood, role in the production of phytoplankton which is responsible for more than 50 per cent of earth's oxygen production.
The IMF report, which focuses on nature's solutions to climate change, estimates if whale stocks could return to their pre-whaling number of more than 4 to 5 million from slightly more than 1.3 million today, it would significantly increase the amount of phytoplankton in the oceans and therefore its yearly carbon capture.
'At a minimum, even a one per cent increase in phytoplankton productivity, thanks to whale activity would capture hundreds of millions of tons of additional CO2 a year,' the report states. 'That is equivalent to the sudden appearance of two billion mature trees. Imagine the impact over the average lifespan of a whale, more than 60 years.'
Wherever whales are found on earth, phytoplankton is abundant. These tiny creatures contribute at least 50 per cent of all oxygen in our atmosphere, and like whales, they capture carbon – the current amount of phytoplankton absorbs about 40 per cent of all CO2 produced on the planet.
Science is not sure why the great whales encourage phytoplankton growth. One theory is that whale waste products contain the substances it needs to survive and grow, specifically iron and nitrogen. Another reason could be that whales raise minerals to the ocean surface when they dive, called 'the whale pump' and through migration, called the 'whale conveyor belt', which provide the plankton with food.
The study, which reviews current research to find 'a low-tech solution' to global warming, says: 'When it comes to saving the planet, one whale is worth thousands of trees… Our conservative estimates put the value of the average great whale, based on its various activities, at more than US$2 million, and easily over US$1 trillion for the current stock of great whales.'
While stocks of great whales have recovered somewhat since commercial whaling ceased 40 years ago, the previous 200 years of slaughter did substantial damage to overall stock levels. For example, population levels of blue whales plummeted by more than 97 per cent. Today whales are still under threat from noise pollution, habitat destruction, shipping disruption to migratory routes and the general decline of the marine environment through global warming and ocean acidification.
A conservative estimate of whale populations pre-whaling is that they stood at around four to five million individuals. Today it is thought there are around 1.3 million whales alive.
'Some species, like the blue whales, have been reduced to only three per cent of their previous abundance,' the IMF says. 'Thus, the benefits from whales’ ecosystem services to us and to our survival are much less than they could be.'
The report suggests that if whales were returned to their pre-whaling size of populations they would capture as much as 1.7 billion tonnes of CO2 annually.