Flawed Estimate Still Worth Making

What’s nature worth?

I mean the whole, blue-green ball of fur, fin, feathers; Amazons to Kalaharis and Everests to ocean muds; lions’ roars and hurricanes to aspens rustling, and the shell-scrape of horseshoe crabs jostling for spawning room on a moonlit beach.

Let’s start with an easy part of the calculation, one of the planet’s biggest, showiest, rarest birds, the whooping crane.

In March, I observed the last wild whoopers on Earth, wintering along the Texas Gulf Coast.

There are only 159, spread out so you’ll not see more than a few any day. Yet more than 100,000 people a year each pay $28 to tour boat operators for a glimpse.

Even if you don’t assign immense value just to knowing such birds still ply their ancient, annual routes, you can agree whooping cranes are economically significant.

Ironically, months later, it is the experience of a less spectacular bird from that trip - a dead duck - that seems most profound.

It was a hen redhead, a species common on the Chesapeake Bay before pollution suffused the shallow-water grass habitats where it fed.

The duck lay on a Gulf of Mexico beach. By the marks in the sand, it had been felled by a falcon, which made a meal of its flesh.

A white-tailed hawk was tearing at it when we arrived; until an even tougher customer, a caracara, planted its fearsome talons against the big hawk and bullied it off the redhead carcass.

It looked as if the caracara would polish off the duck; but our boat drifting nearer made it nervous. It left the remains to a hovering gull, who ate with relish and scarcely a nod to our presence.

No one boards tour boats to see dead ducks.

So how do we assign economic value to this rotting, sunbaked tatter of gristle and bone, which gathered in its flesh the energies of sun and water from grazing grassy shallows across half a continent, then winged south 1,000 miles to become a banquet for falcon, hawk, vulture, gull and, after sunset, perhaps a morsel of dessert for a bobcat or fox?

And how do we set such values against the values touted for more farms and more dredging, which both threaten to pollute sea grasses in Texas bays where some 80 percent of all remaining redheads winter?

Sadly, current economics do a poor job accounting for the “natural services” performed by dead ducks, even though these underwrite the rich community of life that makes nature tourism the fastest growing part of Texas’s $23 billion tourist economy.

Sacrificing grassy bays for cropland and barge channels will reflect only positively in current economic indexes that reflect the value of new crops, more fertilizer sales and extra tractors, but none of the natural trade-offs.

This is more than an abstract exercise in bookkeeping, because we protect only what we value.

We may envision a day when equal weight goes to nature just for what is beautiful and spiritual; in the meantime, we’d better work to give nature its dollars and cents due.

This is the aim of a new book, “Nature’s Services; Societal Dependence on Natural Ecosystems” (Island Press, Washington).

Accessibly written for the lay reader, it features the work of 13 scientists, including the University of Maryland’s Robert Costanza, who runs the Institute for Ecological Economics.

Recognizing the impossibility of putting a true price on the Earth - aesthetic and spiritual values are only touched upon - the authors nonetheless come up with a range of $16 trillion to $54 trillion a year as the value of services provided by natural systems. The human economy, by contrast, is about $18 trillion a year.

The natural services we take for granted range from pollination of plants (human beekeeping is only a tiny part) and pest control to the regulation of climate, floods and the support of global fisheries.

“What would it cost if we had to replace such systems?” Answering that question is one way the book tries to arrive at a value for nature. Even $54 trillion a year is probably conservative, the authors feel.

Conservative, because there is so much we simply can’t comprehend. A square yard of fertile soil, for example, contains literally millions of insects, worms, fungi, protozoans and algae, and billions of bacteria.

Most have never been studied. Which ones, the book asks, and in what mix, would be essential to bring along if we were to try and re-create even the most basic conditions for life on a distant planet?

A calculation fascinating to Chesapeake Bay dwellers is the hugely disproportionate value of the planet’s coastal regions. These include estuaries (like ours), sea grasses, coral reefs and continental shelf fisheries.

They cover only 6.3 percent of the world’s surface, but are responsible for 43 percent of the total value of natural services.

Something like half of Earth’s population lives on only 5 percent of its surface - and much of that 5 percent is right in the superproductive coastal regions.

I think this book is the most important environmental publication in years, a starting point for a desperately needed new view of Earth.

Given its scope, it raises more issues than it answers. For example:

If the vote were all or nothing, we easily would vote to preserve nature’s services. But in real life, we decide based on “marginal values.” Can’t we afford to fill “just one more” acre of wetlands, and then another and another?

And does any attempt to quantify nature’s worth amount to tacit admission that all its value derives from what it can do for one species - us?

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