When it comes to growth, transportation, housing and education are the obvious challenges, but some are not so easily predicted. (Keith Lane/For The Washington Post)

Demographers tell us that a majority of the world’s population inhabits cities and that urban populations will continue rising during this century at an increasing rate.

Two factors primarily fuel city growth: greater job and economic opportunities that attract businesses and people, especially young adults; and the stimulating mix of diverse cultural, social and recreational activities that attract people young and old.

Which raises a fundamental question: Will the world, and in particular the United States, be ready and able to cope with the demographic, economic, social, operational and physical challenges that accelerating urban growth will bring?

Neal Peirce, syndicated writer and editor in chief of Citiscope.org, has written for 40 years about the future of cities, and he addressed this question at a recent meeting of the National Academy of Housing and Cities. The sense of his remarks was that, based on current attitudes, beliefs and behaviors, probably not.

This question also came to mind as I read “Zoned in the USA: The Origins and Implications of American Land-Use Regulation,” written by Sonia A. Hirt. An urban scholar and planner, she is the new dean of the University of Maryland School of Architecture, Planning and Preservation.

Rather than dwelling on the mechanics of zoning, Hirt’s book explains how America’s history, culture, socioeconomic characteristics, political system and real estate market have shaped our cities and suburbs through zoning.

Her analysis focuses appropriately on the potency of the American Dream embodied in homeownership and the detached single-family house. To further drive home her points, she contrasts American land-use traditions, regulations and statistics with those of other industrialized countries — Britain, France, Germany, Russia, Japan — where single-use zones are less ubiquitous.

Reading between the lines of Hirt’s text, I thought about how difficult it would be to effectuate alternative American zoning policies and practices to deal with the complex problems of future metropolitan growth, especially in metropolitan Washington.

These problems relate to transportation and land-use patterns, density, housing affordability, employment, economic fairness, the environment and public education.

Hardly a day goes by when we don’t learn about seemingly intractable problems facing the city, about functional shortcomings and impediments, financial inadequacies, governmental missteps or outright systemic failures. This is why it’s hard to be optimistic about successfully managing our metropolitan future.

Financing, operating, upgrading and maintaining transportation infrastructure are the most frequently publicized challenges. With disparate, continually competing political jurisdictions, and a still mostly auto-dependent population, the future Washington region is likely to remain plagued by insufficient, underfunded public transportation resources.

The sprawling, low-density, single-family subdivisions dominating suburban Washington rely on networks of widely separated arterial and feeder roads, the embodiment of 20th-century, car-centric zoning and planning strategies. Most suburban residential neighborhoods and road networks won’t change. Consequently, suburban traffic congestion, already terrible, will probably worsen.

Will Washington emulate Houston, with future residents driving dozens of miles farther out into Virginia and Maryland in search of cheaper land and less pricey housing? Will innovative technologies somehow improve mobility? Might traffic congestion ease with increased telecommuting, autonomous autos and more people inhabiting walkable communities closer to jobs, with access to transit that might exist in the future?

Skepticism comes easily in light of the many years and enormous expense required to date for the yet-to-be-built Purple Line between Montgomery and Prince George’s counties. Add to this the zeal and litigation with which the Purple Line’s suburban opponents have fought its still-pending implementation.

Metrorail’s Silver Line extension (eventually to Dulles and Loudoun County) took decades of planning and is costing billions of dollars to construct. Yet it’s still unclear whether portions of the county to be served by the Silver Line will be rezoned to enable denser, mixed-use development.

Contemplate how long it has taken and how much it has cost to construct Washington’s streetcar line, intended to be part of a downtown streetcar network that may never be built. Or recall the demise of the proposed Columbia Pike streetcar line in Arlington County.

Long-term infrastructure investment that doesn’t immediately solve today’s problems, or that requires trade-offs adversely affecting some citizens, is always a hard sell.

For a growing number of Americans, finding decent, affordable housing will be increasingly challenging as city populations grow. It’s a big problem for many urban residents because the amount of affordable housing in Washington and other U.S. cities has been shrinking for decades.

Rising land and construction costs, gentrification, fewer sources of public-sector housing investment and subsidy, and conversion of existing units from below-market to market-rate have contributed to the steady decline of affordable housing opportunities.

Then comes the lamentable state of public education in many cities, including the District, and in less-affluent suburbs and exurbs. Will we ever be able to significantly improve underfunded public schools and commit to paying for highly qualified, effective teachers, an indispensable investment in the future?

As if impending growth doesn’t give us enough to worry about, there is a long list of daunting environmental challenges: global climate change; rising sea levels and land loss; loss of flora and fauna habitats; excessive carbon emissions attributable to fossil fuels; and safe disposal of mounting piles of garbage and waste products.

All these problems ultimately stem from fundamental American attitudes, beliefs, traditions and behaviors. Clearly, solving them will depend on money, which probably won’t be forthcoming unless we change our thinking, our policies and our actions.

Roger K. Lewis is a practicing architect, a professor emeritus of architecture at the University of Maryland and a regular guest commentator on “The Kojo Nnamdi Show” on WAMU (88.5 FM).