To the Editor:

David Victor, M. Granger Morgan, Jay Apt, John Steinbruner, and Katharine Ricke ("The Geoengineering Option," March/April 2009) date geoengineering to the twentieth century, but it has been an integral part of the landscape of history. Although Benjamin Franklin wrote in 1751, "We are, as I may call it, scouring our planet, by clearing America of woods, and so making this side of our globe reflect a brighter light," little credit is due to young George Washington's hatchet work. Fire in the hands of Neolithic man had already transformed the ecology -- and the albedo -- of Australia and the Americas eons before.

In recent decades, Foreign Affairs' readers (and editors) have seen the nuclear winter melt down, the energy crisis metastasize into an oil glut, and the population bomb implode. This breathtaking string of global systems modeling fiascos leaves some analysts asking why climate models are deemed sacrosanct when variables as critical as the sensitivity of the climate to the doubling of carbon dioxide in the atmosphere have failed to converge on uncontroversial values.

Cambridge, Massachusetts