cfrw.us Blog

By Katy Human
The Denver Post

The idea of tinkering with the Earth’s climate – once the domain of wing nuts and science fiction writers – is getting a serious look by researchers.

Faced with global warming, scientists are rethinking ideas like sprinkling reflective dust in the atmosphere to cool Earth.

“It could buy us some time … and we need time,” said Tom Wigley, an atmospheric scientist at the National Center for Atmospheric Research in Boulder, Colo.

Wigley’s analysis of spraying sulfur particles into the atmosphere using airplanes or balloons appeared Friday in the journal Science.

In the past 30 years, scientists have proposed a variety of ways to engineer the climate, most of them dismissed as too costly, too unpredictable, impossible or ineffective:

Deploying a giant space mirror to deflect some of the Sun’s incoming rays.

Sending particles high into the sky to trigger cloud formation, rain or snow.

Injecting ozone-healing chemicals into the atmosphere above Antarctica.

Dropping iron into oceans so tiny sea plants will grow and pull more of the greenhouse gas carbon dioxide from the air.

These sorts of ideas are enjoying a resurgence, said John Holdren, president of the American Association for the Advancement of Science and an energy expert at Harvard University in Cambridge, Mass.

Climate change is already occurring far faster than most scientists predicted, Holdren said.

“We’ve seen big increases in the size of wildfires, heat waves, storms, floods, drought, summer melting in Greenland, signs of instability in the West Antarctic Ice Sheet…,” he said.

It will take decades to change the world’s energy systems, which are primarily responsible for the greenhouse gases warming the planet, Holdren said.

“Eighty percent of energy, worldwide, is from coal, oil and natural gas,” Holdren said. “You’re not going to change that overnight, so people are saying, ‘What else can we do?’”

Stall. That’s Wigley’s idea.

The NCAR researcher calculates that the dusty equivalent of a volcanic eruption every year or so could counteract warming for a couple of decades – enough time to figure out ways to cut greenhouse gas emissions.

Sulfur aerosols could be dropped into the stratosphere with airplanes or lifted up in balloons, Wigley said, creating hazy white skies that would scatter some of the sun’s radiation.

This could result in a bit more acid rain, Wigley said, and there are potential problems with ozone depletion. High in the atmosphere, ozone protects the planet from damaging ultraviolet rays.

“I don’t advocate directly that we should do this,” Wigley said. “Rather, I’m saying, this is a serious problem and we should think about all the options.”

Russ Monson, a University of Colorado ecologist, said that while the prospects of global warming are scary, ideas like Wigley’s are “more scary.”

“There are so many potential secondary effects,” Monson said.

At some level, more diffuse sunlight could encourage a forest’s growth, he said, but too little sun would kill plants.