The World Without Us

^{Mountaintop removal, West Virginia.}

^{PHOTO BY V. STOCKMAN, OVEC/SOUTHWINGS.}

If energy-drunk humans were gone tomorrow, all that coal would remain in the ground until the end of time on Earth. If we’re around at least a few more decades, however, a lot of it won’t, because we’ll dig it up and burn it. But if an unlikely plan goes extremely well, one of coal power’s most problematic by-products may end up sealed away once more beneath the surface, creating yet another human legacy to the far future.

The by-product is carbon dioxide, which a burgeoning consensus of humanity agrees probably should not be stored in the atmosphere. The plan, which is attracting growing attention—especially from industry boosters of an oxymoron born of recombinant public relations: “clean coal”—is to capture CO₂ before it leaves the smokestack of coal-fired electrical plants, stuff it underground, and keep it there. Forever.

It would work like this: Pressurized CO₂ would be injected into saline aquifers that, in much of the world, lie under impermeable caprock at depths of 1,000 to 8,000 feet. There, supposedly, the CO₂ would go into solution, forming mild carbonic acid—like salty Perrier. Gradually, the carbonic acid would react with surrounding rocks, which would dissolve and slowly precipitate out as dolomite and limestone, locking the greenhouse gas in stone.

Each year since 1996, Norway’s Statoil has sequestered 1 million tons of carbon dioxide in a saline formation under the North Sea. In Alberta, CO₂ is being sequestered in abandoned gas wells. Back in the 1970s, then federal attorney David Hawkins joined in discussions with semioticians about how people 10,000 years hence might be alerted to buried nuclear wastes at what today is New Mexico’s WIPP site. Now, as director of the Climate Center of the Natural Resources Defense Council, he contemplates how to tell the future not to drill into sequestered reservoirs of invisible gases we might sweep under the rug, lest they unexpectedly burp to the surface.

Aside from the expense of drilling enough holes to capture, pressurize, and inject the CO₂ from every industrial and power plant on Earth, a big concern is that hard-to-detect leaks of even 1/10 of 1 percent would eventually add up to the amount we’re pumping into the air today—and the future wouldn’t realize it. But given the choice, Hawkins would rather try containing carbon than plutonium.

“We know that nature can engineer leak-free gas storage: there’s been methane trapped for millions of years. The question is, can humans?”

3. Archaeological Interlude

We tear down mountains, and unwittingly build hills.

Forty minutes northeast of the city of Flores on northern Guatemala’s Lake Petén Ixta, a paved tourist road arrives at the ruins of Tikal, the largest Classic Mayan site, its white temples rising 230 feet above the jungle floor.

In the opposite direction, until recent improvements halved travel time, the rutted road southwest from Flores took three miserable hours, ending at the scruffy outpost of Sayaxché, where an army machine gun placement perched atop a Mayan pyramid.

Sayaxché is on the Río Pasión—the Passion River—which lolls through the western Petén province to the confluence of the rivers Usamacinta and Salinas, together forming Guatemala’s border with Mexico. The Pasión was once a major trade route for jade, fine pottery, quetzal feathers, and jaguar skins. More recently, commerce includes contraband mahogany and cedar logs, opium from Guatemalan highland poppies, and looted Mayan artifacts. During the early 1990s, motor-driven wooden launches on a sluggish Pasión tributary, the Riochuelo Petexbatún, also carried quantities of two modest items that in the Petén are veritable luxuries: corrugated zinc roofing and cases of Spam.

Both were destined for the base camp that Vanderbilt University’s Arthur Demarest built in a jungle clearing out of mahogany planks for one of the biggest archaeological excavations in history, to solve one of our biggest mysteries: the disappearance of Mayan civilization.

How can we even contemplate a world without us? Fantasies of space aliens with death rays are, well, fantasies. To imagine our big, overwhelming civilization really ending—and ending up forgotten under layers of dirt and earthworms—is as hard for us as picturing the edge of the universe.