The sight the whale-watchers have been waiting for all day long finally arrives. Suddenly, up from beneath the waves, the great sea creature soars into the air. Turning a somersault, it crashes back down again, displacing huge fountains of water. Then, with a final flourish of its tail, it is gone.

Whales have always commanded respect for their enormous size. Blue whales - the largest creatures known ever to have existed - can grow to 30 metres in length and weigh up to 199 tonnes. Now their key role in balancing the environment is also being recognised.

"Whale poo is like environmental gold dust," Anjana Ahuja writes in the Financial Times. "It is rich in iron, phosphorus and nitrogen, among the nutrients that phytoplankton, the algae at the bottom of the marine food chain, need to grow."

Phytoplankton produces over half the planet's oxygen and absorbs four times as much CO2Carbon dioxide. as the Amazon rainforest. These facts underpin the Whale Carbon Plus Project, started by economists Connel Fullenkamp and Ralph Chami. Their plan is to set up a market for carbon credits which is focused on whales and will help conserve them.

The idea behind carbon credits it that if a company is trying to reduce its carbon footprint but fails to reach its target, it can buy a credit from another company which has done so with room to spare. Fullenkamp and Chami want to make investing in whales a way of doing this.

"Ultimately, we're trying to put nature back as something that's valued in our economy," says Fullenkamp.

The hope, Anjana Ahuja explains, is that "the profit motive may succeed in protecting the world's natural resources where governments, industry, environmentalists and philanthropistsPeople who donate generously to good causes. have largely failed".

It is a complicated process. First of all, you need to establish the value of a whale.

This means working out how much carbon is absorbed by the phytoplankton which the whale and its descendants nourish. Added to that is the CO2Carbon dioxide. which is absorbed by the whale itself, and which remains locked in its body for centuries after it has died and sunk to the ocean floor.  

Once the whale's worth as a tourist attraction is also factored in, Fullenkamp and Chami put its value at $2.5m (£2m) to $3m (£2.4m), assuming that it lives for 60 years.

The system also needs to be able to track individual whales across the world - and have accountants who specialise in the creatures.

If all goes well, the profits will be used to restore the world's whale population to what it was before hunting started on an industrial scale - between four and five million.

Yes: Nothing makes things happen more effectively than eager investors, and if Fullenkamp and Chami's scheme works it could transform the environmental movement, with capitalismA form of economy characterised by private property and competition between companies. as a force for good.   

No: The scheme is too complicated and unusual to attract investors, who like tangibleEasily perceptible or real. Tangible changes can be seen or experienced. assets. A whale which roams the world and could die if it becomes stranded is too much of a risk for most.  

Or... The answer may not lie with whales, but it will be a huge step forward if investors can be persuaded that natural resources should be factored into all their decisions and not just taken for granted.