Want to see a bunch of earth scientists completely riled? Say "geoengineering," then listen to the arguments fly.
It's our last resort and might buy us time, supporters say. It's delusional lunacy and could ruin our planet, opponents counter.
Geoengineering most often refers to deliberately altering Earth's atmosphere to slow or halt the climate-changing effects of greenhouse gas emissions like carbon dioxide. Most geoengineering schemes actually do little or nothing to reduce these emissions. But they do spark a host of questions.
"We are talking about a small number of people messing with the whole planet, for heaven's sake," said Duke University geology and civil engineering professor Peter Haff.
The fact that geoengineering climate has received increasing attention in political and scientific circles has scientists like Haff concerned. Some of this concern was expressed at the Asilomar International Conference on Climate Intervention Technologies in California in March, where researchers and policy experts gathered to hash out the ethics and risks of geoengineering.
Much of the historical impact of human technology upon the Earth has been intentional, Haff said, citing agricultural and dam-building as examples. But the side effects of these activities were often unintentional, such as erosion, flooding and biological effects, he said. The difference with geoengineering is that various schemes are designed to intentionally alter our climate, but the unintended consequences are unknown.
"I think geoengineering is dangerous as hell," Haff says. "The consequences are not predictable, but I do think it will be done nevertheless if the pain gets great enough."
An oath for earth scientists?
Intentionally manipulating the atmosphere and oceans calls for newly defined professional ethics, in Haff's view. Haff issued an open call last fall for new doctoral graduates of earth science programs to take an oath that they would do no harm to earth systems. He and a co-author, Erle Ellis of the University of Maryland, wrote that they adapted the idea from Sir Joseph Rotblat, who called for a Hippocratic-like oath for all scientists in the mid-1990s.
The problem, Haff and Ellis wrote in Eos, a newspaper of the American Geophysical Union, is that though the field was founded on understanding earth systems and processes, it's advanced to a point where earth scientists are increasingly being asked to advise decision-makers on how to intervene and directly manage oceans and skies. This new job description spawns new responsibilities for actions with unknown and unintended consequences.
"The article stimulated some significant discussion and was generally well-received but has not been earth shattering, pardon the pun," Ellis wrote in an e-mail.
What N.C. scientists think
Nicholas Meskhidze, a professor in the Department of Marine, Earth and Atmospheric Sciences at N.C. State University, says that while he prefers for people to turn down their thermostats and focus on reducing emissions, he also recognizes that the past 10 years show people are unwilling to conserve.
"If things get to a point where the changes to the climate are so severe that it looks like we might need to use geo engineering, then I think we should go ahead and do the research now to be able to evaluate the consequences," Meskhidze said.
Jose Rial, a geophysicist and climatologist at UNC-Chapel Hill who studies abrupt climate change, said most geoengineering projects "rank from craziness to lunacy." They also detract research dollars and attention from renewable energy technologies with scalable potential - like geothermal, wind, and biomass - and improving efficiencies in buildings and transportation, he said.
"Most of these are cockamamie ideas," Rial said. "They sound interesting in the beginning, but when you start looking into the costs, risks and probabilities of success, then you realize that trying to do planetary change doesn't work." Carbon sequestration - taking carbon dioxide out of the air and storing it - makes the most sense but is problematic, he added.
"The worst part is that these geoengineering ideas give people false hope that we can solve this problem without really sacrificing anything, without changing our habits or devising intelligent policies," Rial said. "We need to abandon this idea that there is a superhuman solution, a silver bullet. There is no such thing."
What are they arguing about?
It's been called planet hacking, Earth tinkering, climate tweaking and putting Earth on life support - but what exactly is the fuss about? Most of today's geoengineering proposals fall into two broad categories: industrial-scaled carbon sequestration to suck carbon dioxide from the atmosphere, and shading the Earth from sunlight.
Carbon sequestration could take the form of giant artificial trees that scrub CO {-2} from the air and then transport liquid CO {-2} into storage beneath the sea or deep in the continental crust.
A variety of solar shading plans have been cooked up, including launching trillions of light-reflecting mirrors into orbit between the Earth and sun to prevent solar rays from reaching the earth and to induce cooler temperatures. Injecting aerosols into the stratosphere is another scheme to create shade by using sulfate molecules that scatter light - pinging some photons back out to space - and causing diffuse sunlight to reach Earth. Some studies have shown that global shading may alter water cycles and affect the growth of crops. Less direct sunlight could also affect solar energy potential.
Another proposal is to fertilize the oceans with iron, which triggers a process of microscopic crustacean blooms that was hypothesized to soak up carbon. But that idea has mostly gone bust after large-scale experiments failed to prove that the induced blooms act as carbon sinks. Some experiments showed ocean fertilization promoted growth of a certain kind of algae that produces domoic acid, a neurotoxin known to sicken marine mammals.
It is unintended consequences like this that give most earth scientists pause.
James Fleming, a science historian from Colby College, testified before Congress last fall that climate engineering technologies could be militarized, might violate international treaties, would do nothing to mitigate ocean acidification and would "alter fundamental human relationships to nature."
