Looking for signs of recovery in our part of the country, we note that homebuilders took out permits to construct nearly 1,900 new residential units in the Baltimore metropolitan area in the first four months of the year. That's a 70 percent rise over the same period a year ago. According to The Baltimore Sun's report on this, there's something of a land rush taking place, with builders snapping up lots "at an aggressive rate," according to John Kortecamp, executive vice president of the Home Builders Association of Maryland.

This is the way we do things — we measure progress in permits for new housing. That's how we define growth, and growth is always considered good, especially as the region and the nation try to emerge from the worst economic collapse since the Great Depression. Foreclosures continue, and many of the people who for a time owned a home have returned, perhaps permanently, to the ranks of renters. But we still look to new housing for evidence of recovery.

We do this, in one sense, out of tradition. Development and construction symbolize the progress of the American Dream, a return to the steady suburbanization of the country. We associate new housing with the period of growth and prosperity that marked most of the second half of the 20th Century, the good old days.

But there are new realities — an extended recession brought on by the collapse of a financial house of cards tied to housing and mortgage-backed securities; long-term unemployment; the erosion of middle-class assets; and massive government deficits. In addition, we face big environmental challenges, a lot of them tied to the supply of energy (Gulf of Mexico), and all of them tied to population growth.

Population growth is hardly ever discussed because, again, growth of any kind is considered good. In Maryland, politicians brag about the prospect of thousands of jobs — and new families — coming our way because of military base realignment. While Maryland made some progress in restricting development with the Smart Growth initiative, and while the O'Malley administration purchased some major tracts of Chesapeake land for preservation, growth still wins the day around here and open spaces disappear.

The fact that homebuilders are getting busy again — and that we still use housing starts as a measure of progress — means we're not quite ready for the concepts of sustainability necessary to meet the realities of the 21st Century.

But we need a real turn toward sustainability: finding ways to use and reuse resources to meet human needs without destroying the environment. It's essential to a future of quality for our children and grandchildren. It's a holistic way of living, working and producing goods to meet the new realities of slow economic recovery, environmental degradation and population growth.

I'm sure the idea of a steady economy — sustaining what we have while satiating the human desire for advancement and affluence — sounds like an experiment in socialism to many. If you believe sustainability incompatible with capitalist enterprise, try this definition from the World Business Council for Sustainable Development: "The delivery of competitively priced goods and services that satisfy human needs and bring quality of life, while progressively reducing ecological impacts and resource intensity throughout the life-cycle to a level in line with the earth's carrying capacity."

Many people who've thought about this a lot are profoundly pessimistic. Growth, they say, is too much a part of the American culture; it's a mantra of business. Developers see open land, they want to build houses on it. Builders want to build new homes; it's easier than fixing up old ones. And people, the pessimists say, will always want to own a new home far from the congestion of the old suburbs and cities — even if that means driving for an hour or more to get to work.

Others are more optimistic. I'm among them. A new generation, more wired than any before it, and primed to live more holistically, is being profoundly influenced by the realities of economic collapse and environmental disaster. We are entering an age when societal survival, and not mere consumerism, becomes the dominant influence, and public policy moves toward sustaining resources, not merely exploiting them.

If we don't get the messages this time and make significant changes, then the pessimists will be correct; we are doomed. But humans are survivors and innovators; there are too many people at work on developing a green economy and fighting other battles for a sustainable future for me to believe that we'll remain a nation that measures progress in the number of new houses we can build on open land.

Dan Rodricks' column appears Tuesdays, Thursdays and Sundays. E-mail: dan.rodricks@baltsun.com. http://www.twitter.com/Midday.