本文作者：小红猪小分队

Source：http://www.newscientist.com/article/mg21628882.000-costing-the-earth-the-value-of-pricing-the-planet.html?

If we are to save the natural world from destruction, must we first put a cash value on it?

IN A rainforest in Guyana, two men are trying to sell rain. If you want, they will also sell you soil, biodiversity, nitrogen-fixing bacteria and all kinds of other things.

Tempted? Thought not. But these men are not con artists. They are engaged in a serious experiment to save the planet: to see whether hard-nosed self-interest can succeed where altruism and politics are failing.

The experiment, run by zoologist Andrew Mitchell of the University of Oxford and banker Hylton Murray-Philipson, takes the form of a private company called Canopy Capital. It does not own the 360,000-hectare Iwokrama forest, but has bought the rights to market its “ecosystem services”. For this it has so far paid half a million pounds.

The services on offer include “the storage of carbon, the generation of rainfall, the supply of water, the maintenance of biodiversity, the prevention of erosion, the formation of soil, the fixation of nitrogen, the treatment of waste and pollution and the support of indigenous and other forest community livelihoods”. Anyone interested in buying these services can do so, in the form of green bonds.

It’s an impressive list. But who would pay for services from a remote rainforest when they already appear to come for free? And what, exactly, would they get for their money? At present the answers are: nobody, and not much. But that is partly the point. The future of the planet could depend on finding some different answers.

Welcome to the weird world of green economics, in which the value of ecosystems is being reduced – or elevated, depending on your perspective – to a matter of dollars, in a bid to save them from destruction.

It makes a certain intuitive sense. Economics and ecology are intimately related, and not just in name (the “eco” in both has the same Greek root,oikos, or “house”). All economic activity is dependent on the environment: what would the timber trade be without forests, or fisheries without fish? And those are just some of the direct connections. Without a stable climate, water to drink and air to breathe, there would be no economy at all.

But at present, the environmental factors that keep economies ticking over are almost entirely absent from economics itself. If they are acknowledged, it is as “externalities” that are not reflected in the prices of goods and services. A classic example is greenhouse gases: emitters emit them for free, and wider society picks up the tab.

To try to plug this loophole, economists have given nature a new name: natural capital. The argument is that only when we can see the true value of nature will we have the incentive to look after it.

This isn’t a new idea. The United Nations agreed a “System of Environmental-Economic Accounts” almost a decade ago. What is new is that global environmental politics is embracing it. Recent international conferences on climate change, rainforests, biodiversity and rivers have endorsed the idea that natural capital can turn the promises of politicians into real action.

So is natural capital really a game-changer? It’s a big ask. One reason natural capital has been ignored is that, by and large, nature is not owned by anyone. Most of it is shared. If you don’t own something, you can’t put it on your balance sheet as an asset. Investing to protect it makes little sense, because you would be giving your competitors a free ride.

The ecologist Garret Hardin put a name on this in a famous 1968 paper: “The Tragedy of the Commons”. In it, he pointed out that shared natural resources with open access quickly get depleted, because everyone has an interest in grabbing what they can, while they can (Science, vol 162, p 1243). This bleak logic plays out in the real world in the form of deforestation, soil erosion, overfishing and so on. It is easy to see the folly of such actions – but why would anyone stop unless they knew that everyone else would, too?

Making matters worse, people are often barely aware that natural capital exists until it disappears – that is, when deforested coastlines are flooded, drained wetlands cease to clean up pollution, razed forests result in droughts, and the trashing of coral reefs causes fisheries to collapse.

The task of green economics, then, is twofold. First, it must overcome ignorance by translating abstruse ecological value into a measure more easily understood – money. Secondly, and more controversially, it must turn that abstract valuation into real money, by finding ways for people to get richer by valuing nature. That way, the argument goes, the unstoppable forces of global capital will be directed towards saving nature rather than destroying it.

The first step, putting a dollar sign on natural capital, speaks to the old business adage that “you can’t manage what you can’t measure”. So what kind of numbers do the green economists come up with?