What Another Hundred Million Would Mean

Oct. 17, 2006 — -- It took the United States:

(— U.S. Census Bureau and various sources)

If --repeat, if --U.S. population grows by yet another hundred million, it could happen soon, well before 2050, say statisticians.

Another hundred million could also change basic equations in America's democracy:

— A quarter of Americans could be Hispanic.

— White non-Hispanics, who were 7 out of 10 in the year 2000, could well dip to around 50 percent … or just below, becoming only the largest among many racial minorities.

— African Americans would likely increase to 14 percent.

— Asian Americans, 4 percent in 2000, would probably double to about 8 percent.

(Americans overall, at 400 million, would become a solid third most populous, behind only China and India.)

And 2 out of 3 Americans would probably live in the West and Southwest.

But that's only if current birth, immigration and migration trends hold steady, which is subject to unpredictables in social attitudes, immigration laws, economic swings, climate change, and the mysteries of ethnic differences in fertility rates.

Far more certain, if the population increases by another hundred million, say experts, is that Americans will need to develop a new relationship to nature's bounty.

Take water.

We have to, since we are, as the aliens in one "Star Trek" episode so memorably dubbed us, "ugly bags of mostly water."

With bodies that are 70 percent water, the now 300 million Americans are already in serious trouble with this most precious liquid.

"In many parts of the U.S., we are already at the limits our natural water supply," water expert Peter Gleick told ABC News. And as number climbs beyond 300 million, Gleick said, "Changes are clearly needed."

For example, when brushing your teeth, do you turn off the tap between applying the toothpaste and rinsing it off the toothbrush -- or when shaving, while scraping your chin?

It may sound extreme, but that's what they do in Bermuda, where there's never been fresh groundwater and they collect the stuff as rainwater from their roofs.

More Americans may be learning such habits as population rises and there's less water to go around.

Water tables are falling fast in much of the west and great plains as drillers probe ever deeper for something clean and fresh, spurred on by drought expected only to increase in coming decades as snowpack melts out sooner each year, leaving summers much drier.

"But the good news," said Gleick, president and co-Founder of the Pacific Institute in Oakland Calif. "Is that we don't have to deprive ourselves - we don't have to stop taking showers -- and we can still be a lot more efficient with the water we have."

In fact, over the last 35 years, while increasing by the latest 100 million thirsty mouths, Americans also made an impressive start in water efficiency not only by adopting better habits, but better technology.

"We used to shower with 5-gallon-a-minute shower heads. Now many are 2 gallons a minute, so in one minute you're saving 3 gallons," Gleick said. "Where we took 6 gallons per flush, now the legal standard is only 1.6 gallons."

"We were using 200 tons of water to make a ton of steel, now we use only 5 tons! And we're using far less water to grow far more food," he said.

As the population grows, more gardens will probably use drip hoses that lie on the ground, downward-facing pinholes dripping water straight into the earth right next to the plants -- which takes a fraction of the water used by traditional sprinklers that soak all the ground and lose a lot to evaporation.

In 1960, none of California's vineyards used drip hoses. Now 70 percent have them.

So far, Americans have managed to lower the gallons of water per person per year from a peak of 708,000 in 1975 down to 547,000, according to U.S. government figures.