Monday, August 20, 2007
Tech Scientist's Idea Could Offset Warming
By John Fleck
Journal Staff Writer
New Mexico Tech scientist Oliver Wingenter believes he has found a way to head off dangerous climate change.
Experiments during the last five years have convinced him and his colleagues that they've found a way to increase cloud cover over Earth's oceans, offsetting some global warming.
"I'm just hoping that this is something that will give us a little more time," Wingenter said in an interview.
But Wingenter said the idea has been a tough sell, and that it has been a struggle to win funding to pursue further research.
The idea is simple. Plankton growing in the ocean emits a gas called dimethyl sulfide, or DMS. DMS, once it gets up into the atmosphere, helps spur cloud formation.
Fertilizing the ocean so more plankton grow could lead to more DMS, Wingenter and a pair of colleagues argue in a paper published last month in the scientific journal Atmospheric Environment. That could lead to cloud formation, cooling the planet and offsetting some of the global warming caused by human-emitted greenhouse gases, they wrote.
The seeds of the idea were planted when Wingenter went to sea for seven weeks in early 2002 to collect atmospheric data as part of a major climate change research experiment.
At the time, DMS and cloud formation were the furthest thing from the scientists' minds. They were trying to see if fertilizing plankton in the planet's southern oceans could slow down global warming in an entirely different way by coaxing ocean plankton to gobble greenhouse gases out of the atmosphere.
Greenhouse gases, primarily carbon dioxide coming out the tailpipes of our cars and exhaust stacks of our factories, are changing Earth's climate, most scientists agree.
World governments are looking for ways to cut emissions and head off the worst damage such change might cause. But such efforts are having limited success, so some scientists have begun to advocate counter measures to offset the warming.
The potential for using plankton to scrub greenhouse gases out of the atmosphere remains uncertain. But when he returned to land and began examining his data, Wingenter realized that the excess DMS he was seeing offered an alternative approach.
In pursuing the idea, Wingenter is entering a scientific-political minefield the field of what is called "geo-engineering."
The most widely discussed geo-engineering proposal, pushed by Lowell Wood of Lawrence Livermore National Laboratory in California, involves a fleet of jets spewing aerosols that would deflect the sun's rays, cooling the planet in the process.
Other suggestions include launching giant mirrors into space to block some of the sun's light.
One risk, said Ken Caldeira, an expert in the field at the Carnegie Institution in California, is that geo-engineering might be used as an excuse to avoid cutting greenhouse gas emissions.
"A world with a lot of greenhouse gases and a lot of geo-engineering might be better than a world with a lot greenhouse gases without geo-engineering," he said.
But by far the less risky course is to minimize greenhouse gas emissions in the first place, Caldeira said.
He likened it to the way a homeowner might use flood insurance as an excuse to build a house in a flood plain.
Wingenter agrees that his idea should not be used as an alternative to greenhouse gas reductions. Rather, he thinks that, as Earth inches toward a climate tipping point of runaway warming, his technique could be used to buy time to make the societal changes necessary to cut our greenhouse gas emissions.
Wingenter cites scientists who say that tipping point could happen within a decade.
Caldeira said that, in principle, Wingenter's idea looks like it might work. But he suggested a cautious approach, with more research to better understand the effect fertilization might have on both ocean and climate.
"It might be relatively benign," Caldeira said. "It might not. We just don't know."