Millennium Just a Blink for Earth
Mar. 28, 1998
NEW YORK (AP) _ In the year 3000, lovestruck newlyweds will still have Niagara Falls to visit. It'll just be in a different place.
Later, when they take the kids on a family vacation, Mount Rushmore and the sweeping vistas of the Grand Canyon will look very much as they do now.
In fact, geologically speaking, not much is going to change in this country over the next 1,000 years.
The hullabaloo over the millennium makes 10 centuries seem like a stunningly long time _ it's 250 presidential elections, and more than 400,000 Broadway performances of ``Cats.''
But for Mother Nature it's just a blink, barely time to clear her throat before doing something world-class like producing a mountain range.
Consider these predictions from the U.S. Geological Survey for the next 1,000 years:
_The coastal mountains that run through Malibu in Southern California will edge upward only about 15 inches. ``That's a rather impressive change for a mountain,'' says survey geologist Diane Noserale.
_Los Angeles and San Francisco will move about 170 feet closer to each other, thanks to slippage along the San Andreas fault.
_North America and Europe will be all of 82 feet farther apart as new sea floor emerges and spreads in the Atlantic Ocean.
Sure, the restless Earth will also twitch so fast on occasion that people will notice. The southern San Andreas fault will probably have about half a dozen big earthquakes by the year 3000. And there's a good chance of a repeat of the powerful New Madrid, Mo., earthquakes of 1811-12, which rang church bells in Boston 1,000 miles away.
A rising sea level could also bring big changes to coastal lands in the next 1,000 years. But for the most part, the processes that cause a wholesale reshaping of a regional landscape need much longer than a mere millennium.
``A thousand years is really a short period for a geologist,'' says Parker Calkin of the State University of New York at Buffalo. ``This is more like archaeological time, I guess.''
Nonetheless, Calkin has some ideas of what Niagara Falls might look like in the year 3000.
Horseshoe Falls, one of two falls tumbling side-by-side there, is migrating upstream at about two feet a year, the geologist says. At that rate it'll move some 2,000 feet, less than a half-mile, by the time those future newlyweds show up.
Its next-door neighbor, American Falls, handles far less water and might move only 10 feet or 20 feet total.
There's a chance Horseshoe Falls could recede much faster. That would happen if the lip of the falls, now a long curve if viewed from above, develops a notch. The water flow would concentrate in this notch like the blade of a buzz saw, and cut upstream at maybe 15 feet a year.
That could create a big change in the next 1,000 years. Horseshoe Falls would retreat far enough to steal the water flow from American Falls. There could be only one falls left.
Calkin isn't predicting a quick march, and he figures water management officials would probably make sure American Falls continues to flow anyway.
So his best bet is little change. Still your basic Niagara Falls.
There sure won't be any reason to update those postcards of Mount Rushmore. Just ask Dan Wenk, superintendent of the Mount Rushmore National Memorial, how much he expects the four faces to change in the next 1,000 years.
``Not much, if at all. I think the public perception will be really no change at all.''
Erosion is thought to eat away only one inch every 10,000 years.
Taking a long view, the monument's caretakers are studying three of the mountain's huge granite blocks. One is below George Washington's right ear, another in Theodore Roosevelt's hairline, and the third on the right side of Lincoln's face. These blocks have less natural support than others and someday they may fall out.
But not in the next 1,000 years.
Same story in Hawaii, where vacationers with a very long view can look forward to a new island called Loihi. It's now a volcano rising more than two miles from the floor of the Pacific, about 21 miles south of the Big Island.
Want to be the first on your block to stroll on its beach? Forget it. Loihi is still more than a half-mile below the surface, and it won't break through for at least another 50,000 years.
To be sure, the forecast for the next millennium isn't all ``more of same.''
Take the Grand Canyon. Its vistas will be about the same, but people who enjoy boating or running its rapids might have to cope with changes by the year 3000.
The Colorado River, which winds through the canyon, has been controlled by the Glen Canyon Dam since 1963. The dam prevents the river from flooding. And that means the river can't clear out sand, silt and boulders dumped in by its tributaries.
So far, buildup of sand and silt hasn't been a problem because the tributaries have been delivering very little of the stuff. But Ted Melis, the physical scientist at the federal Grand Canyon Monitoring and Research Center in Flagstaff, Ariz., figures that's just a temporary phase _ one that could easily reverse itself over the next millennium.
What then? Here's the scenario Melis sketches, assuming that the Glen Canyon Dam and its successors continue to control the river:
The Paria River, which enters the Colorado below the dam, could resume dumping huge amounts of sand. Boaters for dozens of miles might get stranded on sand bars almost as soon as they set out from shore. The National Park Service might get pressured into starting permanent dredging to keep the river usable.
Then there are the boulders. Streams and rivers can deliver rocks as big as 20 feet across, but more typically about six feet wide, along the Colorado. In the past, floods on the Colorado washed away all but the biggest boulders, which formed the foundation for rapids that attract thousands of adventurers.
But with no more flooding, lots more of these boulders could pile up on the rapids by the year 2550 or so, making them too steep to run. Some could become waterfalls.
``You might just go from one insurmountable drop to the next, which might be only a half mile downstream,'' Melis says.
He suggests that a new sport might emerge: going over these waterfalls in high-tech barrels.
The outlook for people who'd rather run rapids isn't all bleak. About 75 miles below the dam, the Little Colorado River enters the Colorado. It's the biggest tributary and still runs wild, Melis says, so it might produce floods big enough to wash away boulders in the Colorado and preserve usable rapids downstream.
America's most famous river, the Mississippi, might also change by the year 3000. The wild card is the prospect of global warming. That could melt polar ice sheets and raise sea levels. That would basically make the Gulf of Mexico march upstream on the Mississippi.
Scientists are still debating what will happen to sea level. One nightmare scenario suggests a 30-foot rise over the next 1,000 years. But Roger Saucier, an expert on the lower Mississippi River, says even a rise of 10 to 15 feet ``would just about wipe out virtually all of Southeast Louisiana.''
The coastline would be well north of New Orleans, probably near Baton Rouge, a change of 75 of 100 miles inland, he says.
Saucier, who's retired from the U.S. Army Corps of Engineers, says the changes wouldn't stop there: As the river adjusts to the new sea level, it would produce higher floods nearby, forcing people to build higher and higher levees.
South of Vicksburg, Miss., or Natchez, Miss., ``we would soon reach a point where it's probably going to become economically impractical to try to continue flood control as we know it now.''
That might inspire measures like straightening and widening the river to let water run downstream faster, or dredging new canals to carry off some of the flow, he says. Or people might just move away from the endangered areas and let nature reclaim them as swamps and forests.
But what about that symbol of American continuity, that soaring icon to dependability, that sight that's awed generations of tourists?
How about Old Faithful?
For more than a century, it has gushed about 20 times a day, predictable to within 10 minutes. But, by the year 3000, will it still be there?
Hard to say, replies naturalist Ann Deutch at the Old Faithful Visitor Center. Even 100 years is a long lifetime for a geyser that big.
But future vacationers need not be discouraged. Even if Old Faithful is gone, she expects Yellowstone Park will still have other geysers ``as big, as beautiful, as powerful.''