It would, of course, have taken a miracle worker to get the farmers to pay for a service they had always gotten for free. But before that could happen, technology and market forces intervened: BT cotton, a strain of cotton genetically modified to produce the insecticide BT, came on the market. The BT took over the job of controlling insect pests on cotton farms, and suddenly the free-tailed bats were like buggy-whip makers in the automotive age or newspaper reporters today. The value of their services plummeted by 80 percent.

Cases like this have led a lot of biologists to wonder, as the title of a recent article in the journal Trends in Ecology and Evolution put it, “Have Ecosystem Services Been Oversold?” These critics increasingly question the validity of the entire ecosystem services movement on practical and moral grounds. They ask, among other things: What happens when technological and market forces make the services a species provides, and thus the species itself, seem worthless? Is it even right to monetize and in some cases privatize nature, the ultimate public good?

The questions are worth asking because the ecosystem services idea is a movement, beloved by many conservation organizations, and the subject so far of more than 15,000 peer-reviewed articles in scientific journals. Schemes to pay for ecosystem services, such as REDD, are also a big deal in global financial markets. You might think REDD is a brand of apple ale with really stupid television advertising. But it’s an international program, arguably overhyped, called Reducing Emissions From Deforestation and Forest Degradation.

The idea behind REDD is twofold: Forests sequester carbon, harbor biodiversity, and otherwise provide ecosystem services. So why not get corporations, governments, and others to pay to protect those services, if only to offset their own carbon emissions or earn public relations bonus points? Thus Norway, a leader in the movement, has pledged $3 billion under REDD schemes to protect threatened tropical forests in Brazil, Indonesia, and other countries. This is serious money being put to work to protect natural resources, so you can understand why conservation groups might love the idea.

But much as was the case with the free-tailed bats, “there are no markets for many of the goods and services that ecosystems provide,” Jonathan Silvertown, an evolutionary biologist at the University of Edinburgh, points out in the “Oversold” article. The solution for ecosystem services proponents, he writes, has typically been to “invent a market” like the REDD scheme for carbon credits. Or they “pretend there is a market” and ask people how they would value ecosystem services in hypothetical situations. But “make-believe markets” are highly likely to fail when people are otherwise, he writes.

But make-believe markets are highly likely to fail when people are otherwise relentlessly focused on nickel-and-dime realities. The market mentality also degrades nature by attempting to turn it into a commodity. “People are not allowed to sell their organs or their children,” Silvertown writes, citing the 2012 book What Money Can’t Buy: The Moral Limits of Markets. “These have intrinsic value that is beyond price.” That’s true of species and habitats too.

The attempt to sell nature went spectacularly wrong for the government of British Prime Minister David Cameron. When he came to power in 2010, he pushed to sell off the roughly 1,000 square miles of forest that until then had been owned and protected by the national Forestry Commission. The ecosystem services idea seemed to offer the new government a bright, shiny “technocratic rationale for the deployment of its natural capital,” Silvertown writes, with the added likelihood of putting bright, shiny millions into government coffers.

Some conservation groups went along, “taking the view that it is regulation” of the forests “and not ownership that matters.” But Cameron, a conservative, was slashing regulations at the same time. The response from the British public was furious. It turned out that no amount of money could make up for what it perceived as the loss of its forests, and no amount of monetizing could capture the value of simply being able to walk in the woods. Cameron quickly backed down, with one government source describing the whole idea as “a cock-up,” or what Americans might call a FUBAR: “We just did not think.”

So, let’s think. Where does all this leave the ecosystem services idea? Trying to “unbundle” all the things we get from the natural world and put a price on them cheapens nature, and it cheapens us. The people who first developed the idea in the mid-20th century meant that conservation could benefit from showing people how their lives depend, in all sorts of unseen ways, on the natural world: Intact wetlands save downstream cities from flooding, coastal marshes serve as nursing grounds for offshore fisheries, and that air you breathe? Yes, it’s an ecosystem service, provided by healthy forests and obscure ocean microorganisms.

This is the only sense in which the ecosystem services idea deserves to live—as a constant reminder of how utterly we all depend on the priceless blessings of the natural world.

[Richard Conniff is the author of House of Lost Worlds: Dinosaurs, Dynasties, and the Story of Life on Earth, and other books.]