Putting a Price Tag on Nature’s Defenses

Protection from storms is just one of many services that ecosystems provide us — services that we’d otherwise have to pay for. In 1997, a team of scientists decided to estimate how much they are actually worth.  Worldwide, they concluded, the price tag was $33 trillion — equivalent to $48.7 trillion in today’s dollars.  Put another way, the services ecosystems provide us — whether shielding us from storms, preventing soil erosion or soaking up the greenhouse gases that lead to global warming — were twice as valuable as the gross national product of every country on Earth in 1997.

“We basically said, ‘It’s an imprecise estimate, but it’s almost definitely a pretty big number, and we’ve got to start paying attention,'” said Robert Costanza, a professor at Australian National University who led the study.

That study proved to be hugely influential.  Many governments, from Costa Rica to the United Kingdom, started to take the value of ecosystem services into account when they planned environmental policies.  But the study also set off a lot of controversy.  Some economists argued that it was based on bad economics, while some conservation biologists argued that price tags were the wrong way to save ecosystems.

Seventeen years later, the debate is getting re-energized, just as the nation becomes immersed in an intense fight over the Obama administration’s attempt to tackle the emissions that scientists say could threaten many of these ecosystems.  Dr. Costanza and his colleagues have now updated the 1997 estimate in a new study, published in the May issue of the journal Global Environmental Change, and concluded that the original estimate was far too low.  The true value of the services of the world’s ecosystems is at least three times as high, they said.

“As we learn more, these estimates increase,” Dr. Costanza said.

That’s putting it mildly.  The enormous rise in the price tag stems from hundreds of new studies carried out on ecosystems around the world.  Taken as a whole, these studies reveal that ecosystems do more for us than Dr. Costanza and his colleagues could appreciate in 1997.

Putting a Price Tag on Nature’s Defenses