Cool Ideas

By: Mike Ransdell

Carnegie Mellon researcher devises strategy to combat global warming

The ocean is growing. It has coastal cities such as Miami in its sights. It's creeping up the coastline slowly and methodically to claim new territory. It could swallow up white, sandy beaches; hotel lobbies; and airport runways. It could seep into downtown streets, onto interstates, and over seaports. It could wreak havoc on the ecosystem, displace low-income residents, and contaminate water supplies. It won't happen overnight. In fact, it could take a century or more. But a growing number of researchers, politicians, and executives of major corporations agree that it's on its way. The question is, what to do about it.

The dilemma facing Miami began thousands of miles north in Greenland. A mammoth icecap is melting at an alarming rate by some estimates. If the deterioration increases, the sea level could rise by as much as 7 feet by 2100, making much of downtown Miami, at just 5 to15 feet above sea level, and Miami International Airport, whose runways are 9 to 10 feet above seal level, vulnerable to rising tides and storm surges.

Granger Morgan, professor and head of Carnegie Mellon's Department of Engineering and Public Policy (EPP), used this extreme scenario as a backdrop for a qualifying exam for doctoral students in EPP. The students, playing analysts, were charged with exploring various options for helping a hypothetical Miami real estate holding company to chart a future course based on a "worst case" of such a sea level rise. There's no denying that the Greenland ice cap, which is above sea level, is shrinking. And there's no denying that as it thaws it's raising the level of the ocean, which has the potential to gradually devour chunks of low-lying islands and cities such as Miami, New York, London, Hong Kong, and Tokyo ... though probably not as rapidly as the EPP exam suggested. And there's no denying the cause—global warming.

Destruction to coastal cities from an expanding ocean is just one potential crisis. Climatologists are warning of a variety of problems that could be set off by rising temperatures: more frequent and more severe hurricanes, droughts and heat waves, dramatic changes in ecosystems, diminishing water supplies and shriveling crop yields in developing countries, increasing numbers of animals threatened with extinction, and disappearing of coral reefs and mangrove swamps, which are important food sources for sea life. And on and on. It's no wonder the issue has captured the attention of scientists from around the world.

Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) released a summary of its much anticipated fourth report, "Climate Change 2007." More than 2,500 scientific experts from 130 countries contributed to the work, which took six years to complete. Their findings present a sobering assessment: "Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level. Eleven of the last 12 years (1995-2006) rank among the 12 warmest years in the instrumental record of global surface temperature."

The report goes on to finger the main culprit: "Carbon dioxide [CO₂] is the most important anthropogenic greenhouse gas. The global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 ppm [parts per million] to 379 ppm in 2005. The atmospheric concentration of carbon dioxide in 2005 exceeds by far the natural range over the last 650,000 years (180 to 300 ppm) as determined from ice cores."

The magnitude of the effect makes it abundantly clear that this is much more than a statistical aberration. And it certainly wasn't a surprise to Morgan, who also serves as professor in the Heinz School and Department of Electrical and Computer Engineering. "Everybody knows in the science community that the greenhouse effect is real, and if you add more CO₂ to the atmosphere, you're going to heat it up," he explains. "There's really no uncertainty about that, though there is an uncertainty about the details of how many of the changes will play out."

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