Planning for uncertainty

by Paul Larmer

On an unseasonably cold night in late January, more than 250 Phoenix-area residents packed the Arizona State University Kerr Cultural Center in Scottsdale. There, they found more than just physical warmth: High Country News was sponsoring a heated conversation on the uncertain future of their desert kingdom. Author and moderator Craig Childs posed the central question: In an era of climate change and global instability, would Phoenix, population 4 million and growing, continue to thrive, or would it decline as its predecessor, the Hohokam civilization, did some 1,300 years ago?

The panelists were cautious, but somewhat optimistic: Prolonged drought would challenge Phoenix, said Rita Maguire, former director of the Arizona Department of Water Resources, but the city is preparing by storing large quantities of Central Arizona Project water (from the Colorado River) in depleted aquifers.

But what if the Colorado River dries out as radically as some scientists predict? The state would get creative, said Maguire and attorney Grady Gammage, a research fellow at ASU's Morrison Institute. First, it would buy out the remaining agricultural water in the Phoenix Valley (farms still use most of the valley's water), and then it might build desalination plants on the Pacific Ocean for California, in exchange for its neighbor's share of the Colorado.

"I don't think water is necessarily the limiting factor on Phoenix's growth," said Gammage, who has a penchant for provocative statements. "The limiting factor might be the quality of life. How many people will want to live here when the nighttime lows in the summer are 100 degrees?" Last summer, Phoenix topped 110 degrees 31 times, with nighttime lows in the mid and upper 90s. Climatologists blame the heat on an "urban heat island" effect created by all of the heat-absorbing pavement and rooftops. Gammage predicted that Phoenix's population could rise to between 5.5 and 7 million before conditions got unbearable. State Rep. Chad Campbell said the time to slow down growth and embrace green land-use patterns is now; he said he will push the Legislature to put some teeth into the state's tepid growth management act, so local officials can turn down or modify proposed developments.

Slowing down growth won't be a priority, the panelists concluded, until residents are hit hard by water and power shortages. But judging from the turnout at the event, and the audience's pointed questions, I'd say many locals are ready to act now. Planning for a world with a rapidly changing climate is not just a problem for urban areas. As M. Martin Smith and Fiona Gow explore in this issue's cover story, park managers and scientists are struggling with how to respond to ecological shifts caused by climate change. Should they aggressively intervene to preserve dying populations of animals and plants, or just let "nature" take its course?

What is the right answer? Intervention may be the best option for some species, but the primary strategy for protecting biodiversity remains unchanged: Keep as much land as possible undeveloped so plants and animals can freely move in response to climate change. That's a strategy more Phoenix leaders need to embrace.

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