A team of economists have attempted to put a dollar value on the contribution whales make to fighting climate change. They've come up with some truly astounding figures, with typical whales being worth $2 million dollars each, making for a cumulative large cetacean value of more than a trillion dollars.
Whales feed in nutrient-rich waters off continental coasts or at great depths, and then return those nutrients to areas that need them more in the course of their great migrations. Unlike fish droppings, which mostly sink to the ocean floor, whale poop floats where surface algae can get at it.
The result is that algal phytoplankton get the nitrogen and iron, among other things, they need to flourish. This allows them to draw carbon from the air, some of which eventually gets taken to the bottom of the oceans as the algae, or whatever feeds on them, die.
The Great Whale Conservancy commissioned some economists, led by Dr Ralph Chami of the International Monetary Fund, to calculate whales’ value as nutrient recyclers. Their work has been published in Finance and Development. It would be fair to say with a sponsor like that the authors are not entirely impartial, but even results a tenth of what they present would be staggering.
The paper begins with the line; “When it comes to saving the planet, one whale is worth thousands of trees.” By stimulating phytoplankton growth, whales contribute to the 37 billion tonnes (41 billion tons) of CO2 these tiny ocean creatures draw from the atmosphere each year.
Today there are an estimated 1.3 million whales in the world, down from 4-5 million before industrial hunting, so the oceans have the capacity to support many more. The authors calculate restoration of previous whale numbers would boost oceanic drawdown by 1.7 billion tonnes (1.87 billion tons) of CO2 a year.
Some species bounced back quite well once large-scale hunting stopped, but blue whale numbers are estimated at just 3 percent of their pre-industrial levels. The recovery is being affected not just by continuing whaling from Japan and Norway, but ship strikes, underwater noises, and marine plastic.
Carbon sequestration accounts for the bulk of the trillion dollars the paper estimates whales are worth, although this depends on the value placed on each ton of carbon dioxide removed from the atmosphere. Whales also enhance the value of the fishing industry, since fish feed on the plankton whales fertilize, as well as being valuable drawcards for tourism.
An accompanying briefing paper suggests the best way to protect whales from the major threat of ship strikes is to pay shipping companies to avoid their migration routes and breeding grounds, even at the cost of longer routes, but acknowledges the problem of who should pay.