Without air conditioning, the Sun Belt as we know it would not exist today. It is as simple as that. You would not have people in office buildings in Houston, in microchip factories in Phoenix, in oil company skyscrapers in New Orleans or giant office parks in north Dallas, boutiques and continental restaurants in Atlanta, shopping centers and subdivisions rising out of swamps in Florida. There would still be a South, of course, but it would be a lot more like the old, less productive South of 1950. There would still be oil wells in Texas, but there would be much less economic innovation and growth there.

The reason is simple: without air conditioning, you wouldn't get much work done in offices in the South. The steamy weather which caused New York's Mayor Robert Wagner to give city employees Friday afternoons off in the summer was the norm in the South: it would be above 75 degrees most working days of the year. Fans would blow on the floor any papers not battened down; shirts would be rolled up, ties askew, sweat appearing under arms; women would wear short-sleeved dresses and still their skin would get sticky. Everyone found it hard to concentrate on work. It is no accident that no highly productive capitalist economy has arisen in a tropical or semitropical climate until air conditioning came along.

Now one has. Congressmen from the Northeast like to bemoan the fact that their states' incomes are no longer much above the national average. But that is true in large part because states in the Sun Belt have incomes much closer to the national average than they used to. Georgia, for example, had in 1980 a per capita income only 9 percent below the national average and Texas only 1 percent below the national average; corresponding figures for the pre-air-conditioning age--1950--are 31 percent and 10 percent. And this income is broadly distributed. In Georgia and Texas 16 percent and 15 percent of residents were living in poverty in 1980--only marginally higher than the national figure of 12 percent.

Other factors have contributed to the Sun Belt's growth; foremost among them, I would argue, is the civil rights revolution, which has made many blacks more comfortable and productive in the South than they were even 20 years ago. But air-conditioning may turn out to be more important. For all our paeans to the glories of pristine nature, the fact is that the control of temperature has been critical to the advance of civilization: the control of fire enabled man to survive outside the tropics, the refrigerated freight car enabled people who lived in thickly populated areas to eat meat regularly, and the air conditioner has spread the most advanced and productive form of civilization man has achieved to Atlanta and Houston and Los Angeles and Singapore. Those who bemoan the forms this civilization takes should, in justice, be required to do so in an office with one window opened and a single fan whirring on the kind of steamy day Washington has been enjoying recently.