April 29, 2008

U.S. Population to Top One Billion

LAS VEGAS — A billion people will be sharing the United States sometime between 2100 and 2120, in a lifetime more than tripling the current population.

That prediction is according to Arthur C. Nelson, FAICP, who will present his findings today at the American Planning Association's (APA) 100th National Planning Conference, taking place in Las Vegas through May 1.

This is thought to be the first time a planning scholar or professional has predicted that it is even possible that the U.S. will reach the one billion mark. In fact, other than a brief treatment of the prospect in a 1999 U.S. Census Bureau report and a few small references to that report thereafter, it appears there has been no published discussion of the possibility.

An expert in estimating population changes and their impact on planning and economic development, Nelson is currently professor in Urban Affairs and Planning, and co-director of the Metropolitan Institute at Virginia Tech. Among many books, he is the author of Planners Estimating Guide: Projecting Land-Use and Facility Needs, published by APA's Planners Press.

In the 1999 report, now dated from the perspective of population analysts, the U.S. Census Bureau predicted a population low estimate of 282 million and a high estimate of 1.18 billion by 2100.

Jeff Soule, FAICP, APA's Director of Outreach and International Programs, said: "While there is room for discussion on Dr. Nelson's prediction, the current fact is that U.S. population will grow a good deal and we must begin planning now if we are to meet the needs of the 22nd century."

Some may wonder how any prediction — about 95 years away — should matter to us today. Nelson says that with increasing longevity, even some people in their early 20s now could be alive to see the billionth person arrive.

He argues that now, sometimes the planning horizon is too short and we should be thinking at least 95 years in the future. In other cases, officials are planning a century or longer out, but most citizens don't realize it. For example:

• Public water supply systems often have a 100-year planning horizon, and there is an argument for thinking 500 years out.
• Major rail transit facilities take up to two or three decades to plan and another one or more to build.
• Airports were built less than 50 years ago with the thought they would never need to be replaced, but many have been, with more planned.
• We know enough now about the threat of climate change to shape planning for coastal communities over the next century.
• Government involves many fixed investments that in order to be economical must be paid off over a long period of time.

Nelson examines fertility, longevity, and other factors in arriving at his prediction.

He compares worst-case outcomes with planned scenarios to address factors like sufficient supplies of water and farmland, ability to reduce building and industrial emissions, and adequacy of transportation infrastructure.

But he is optimistic that the U.S. has the capacity and is better prepared, perhaps more so than any other country, to accommodate such growth — if we begin planning for it now.

Since Nelson's projection is new and unpublished, there has not been time for full debate as to how realistic it may be. Just across the hall at Virginia Tech, associate professor in Urban Affairs and Planning Robert E. Lang, co-director of the Metropolitan Institute there and Nelson's colleague, thinks the number is "improbable." Also speaking at the APA conference to provide an alternate view, Lang believes that there will be 400 million people in the U.S. by around 2040. Some experts, including Lang, are comfortable making only such shorter-term predictions.

Both Lang and Nelson agree that the U.S. population is growing fast and that we have to plan for a range of possibilities that could include a high side of one billion between 2100 and 2120.

"This is a wake-up call that ought to get people thinking about a bigger view of the future," said Nelson. "They are going to live longer, and we have to plan for that. It is not just the number, it's what is driving the number."

He concluded: "The impact of U.S. population growth will probably come crashing into us sooner in the future than we realize. We can meet the challenges — if we plan for it. We need to begin asking the right questions, and get prepared psychologically and politically. Then we need to plan on how to manage America at one billion residents."

Contacts

Roberta Rewers, APA, 312-786-6395; rrewers@planning.org
Marc Breslav, 845-265-2624