If A Walk On The Flat Side , The Twilght's Cold Glare , or my August 2000 Forbes article Paint The Town White intrigued you, stay tuned - Science reports :
Tinkering with the Climate to Get Hearing At Harvard Meeting
Should scientists and engineers seriously consider large-scale alterations of the climate to stave off the worst effects of global warming? Several dozen top U.S. climate scientists will explore that controversial question next month in a 2-day invitation-only workshop at Harvard University designed to explore whether direct interventions might be needed to supplement efforts to reduce greenhouse gas emissions.
Curbing greenhouse warming manually, so to speak, could offer a more immediate and possibly simpler solution to climate change than the massive overhaul of energy systems that would be needed to cut global greenhouse gas emissions. Ideas include removing CO2 from the atmosphere by forcing air through absorbers or stimulating plankton growth, and shading the planet with aerosols. But many prominent climate scientists have been leery of even discussing such possibilities for fear that they could provide policymakers with an excuse not to cut carbon emissions, or that the technology comes with serious side effects. As a result, says Harvard geochemist Daniel Schrag, who is organizing the meeting, discussions have occurred mostly among advocates. "I wanted to get the mainstream climate community … to look closely at this thing," he says.
The 8 to 9 November meeting will include climate heavyweights such as James Hansen of NASA, Kerry Emanuel of the Massachusetts Institute of Technology in Cambridge, and Mark Cane of Columbia University. Its focus will be on ways to lower the atmosphere's temperature, including releasing massive amounts of sulfates into the atmosphere to mimic the natural cooling effects of volcanic eruptions. Such an approach was publicized last year by Nobelist Paul Crutzen, an atmospheric chemist at the Max Planck Institute for Chemistry in Mainz, Germany (Science, 20 October 2006, p. 401).
Solar shield. The University of Arizona's Roger Angel has calculated that trillions of orbiting disks could refract sunlight and reverse catastrophic global warming.
CREDIT: TOM CONNORS/ROGER ANGEL/JOHANAN CODONA, COPYRIGHT ARIZONA BOARD OF REGENTS
Scientists pondering geoengineering ideas argue that such cooling schemes could be hard to control and wouldn't address the acidification of the oceans caused by CO2. Others worry that any discussion of the topic will undermine political momentum to cut greenhouse gas emissions. These include atmospheric scientist Elisabeth Moyer, who before leaving Harvard for the University of Chicago told Schrag that the conference should be held off campus or without publicity. "I had concerns about lending the conference the prestige of the Harvard name. … The conference can be viewed as an endorsement [of geoengineering]," she says. Even so, Moyer thinks that "it is critical to discuss the idea."
Hansen says better forest practices, advanced agriculture techniques, and geologic carbon sequestration could supplement the real emission cuts required to stave off dangerous climate change and avoid the need for geoengineering efforts. He hopes to spread that message at the meeting. "The potential for stabilizing climate is more than realized," he says. But he agrees with Schrag that geoengineering should still be explored, as future policymakers might seek to do it whether or not scientists understand it. "I don't think scientists should shy away" from the topic, he says.
The fact that the meeting is taking place at all marks a new phase of urgency among climate scientists, says modeler Ken Caldeira of the Carnegie Institution of Washington in Stanford, California. In a 1998 paper, Caldeira called the aerosol approach "a promising strategy," although he argued that emissions cuts remain "the most prudent" course of action. "A decade later, a bunch of people are coming to the same point," says Caldeira.