Phoenix: is paradise becoming hell on Earth?

As the Earth breaks into a global warming-induced sweat, animals are reportedly migrating into northern latitudes once regarded as too cold for them. They must be tripping over the one species headed the other way, as human beings continue flocking south to the Sunbelt. And Phoenix is as sunny as it gets, and as hot. Hundred-degree days are the norm from late May to October. Highs of 105 are typical, and 110-degree scorchers all too common. In June 1990, the mercury hit a record 122 degrees.

And it's getting hotter. Global warming and runaway development could make Phoenix hell on Earth--with freeways. "It's a double whammy," says William Sprigg, deputy director of the University of Arizona's Institute for the Study of Planet Earth. Sprigg helped oversee an institute and U.S. government study of global warming's effect on the Southwest and Phoenix. The 2000 report concludes: "The seasonal extremes will ... likely exceed anything in the recent historical record."

And the record hasn't been all that comforting. Even without global warming, Phoenix has been the poster child for what's known as the heat-island effect. Asphalt radiates solar heat like a stovetop, creating a heat island where farmlands and desert have been paved over to make room for tract housing and some four million vehicles. The heat island has become a large land mass.

Anthony Brazel, director of the Southwest Center for Environmental Research and Policy at Arizona State University, says Phoenix used to cool off at night in mid-summer. That changed with the heat-island effect. "We've had nights when the temperature doesn't even get below 90 or 95," Brazel says.

Phoenix is among the most air-conditioned cities on the planet, though keeping cool is costly and the poor often need assistance to pay summer electric bills. Phoenix--despite the Western drought--still has water aplenty, largely diverted from the Colorado and Salt Rivers. The city is an oasis of grass lawns and leafy trees. But all this green comes at a price, Sprigg says. The plants release water vapor and increase humidity, making it harder to excuse the searing temperatures as "dry heat."

Brazel says some non-native plants succumb no matter how much water is dumped on them. "A lot of ornamental plants just shut down because it's too hot," he says. CONTACT: Institute for the Study of Planet Earth, [phone], www.ispe.arizona.edu; Southwest Center for Environmental Research and Policy, [phone], www.scerp.org.