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(CNSNews.com) - Government scientists are studying the feasibility of sending nearly microscopic particles of specially made glass into the Earth's upper atmosphere to try to dampen the effects of "global warming." The idea, while "interesting," said one leading global warming skeptic, is "not practical" and, if done on a large scale, could depress the ozone layer and cause other problems.

Details from documents Cybercast News Service obtained under the Freedom of Information Act show that scientists at the U.S. Department of Energy's (DOE) Savannah River National Laboratory in Aiken, S.C., are developing computer models of what might happen if a huge amount of particulate matter is shot into the stratosphere.

The particles, consisting of a very fine and special form of glass - "porous-walled glass microspheres" - would be able to absorb a certain amount of carbon dioxide, and would reflect sunlight away from the Earth.

"The overall goal of this task is to understand and evaluate the implications of deploying porous glasses as an agent to reduce global warming," the DOE work proposal said.

The government project began last year and ends on April 30.

The Department of Energy did not speak with Cybercast News Service about the project, but scientists familiar with the line of research say it grows out of a proposal first articulated by Paul Crutzen, who won the 1995 Nobel Prize for his work discovering that there is a hole in the ozone over the Antarctic.

Crutzen proposed sending aircraft 747s to dump huge quantities of sulfur particles into the far-reaches of the stratosphere to cool down the atmosphere.

"The droplets reflect back incoming solar radiation," said Tom Wigley, a scientist with the National Center for Atmospheric Research in Boulder, Colo. "We're trying to change the net amount of incoming solar radiation into the Earth's atmosphere."

Wigley, one of the country's biggest advocates for injecting aerosols into the stratosphere, said the idea of placing particulate matter into the top reaches of the atmosphere isn't much different than what already happens when volcanoes erupt.

"We're putting a lot of aerosols into the lower part of the atmosphere, the troposphere, already," he told Cybercast News Service. "We're doing that because sulfur dioxide is a byproduct of burning fossil fuels, just like carbon dioxide is. And the lifetime of those aerosols in the troposphere is only a few days to a few weeks. In the stratosphere, that lifetime is a year or several years."

The longer the particles are in the stratosphere, the more cooling they could theoretically affect. Glass particles would be less likely than sulfur particles to form acid rain when they fall to the Earth.

Wigley, who is also one of the foremost advocates for the idea of global warming, is himself engaged in research on similar proposals to mitigate the effects of carbon dioxide, which many scientists say is a major factor in global warming.

Proposals like the injection of aerosols into the upper atmosphere are referred to as "geo-engineering."

"Geo-engineering is the intentional large-scale intervention into the environment to counteract anthropogenic (our human-caused) climate change," Wigley said.

Reducing use of fossil fuels alone will not stop global warming, according to Wigley.

"Geo-engineering may give us time to develop the technologies that will allow us to move away from energy sources that put CO2 into the atmosphere," he said.

'Waking up to the facts'

Perhaps surprising, scientists who question whether global warming is a real phenomenon say they have no problem with geo-engineering or with scientists studying possible solutions like atmospheric aerosols.

Such geo-engineering proposals are only in the embryonic stages, said Fred Singer, president of the Science & Environmental Policy Project.

"It's an academic exercise," Singer said. "It's not practical, and I'm not sure it's necessary. But it's interesting."

However, Singer, a scientist well-known for arguing that global climate change is a natural phenomenon and not man-made, said there could be real-world - and unwanted - side effects if we ever test such theories on a large scale.

"If you do this on a continuous basis, you would depress the ozone layer and cause all kinds of other problems that people would rather avoid," Singer told Cybercast News Service .

Patrick Michaels, a research professor of environmental sciences at the University of Virginia and a senior fellow at the libertarian Cato Institute, said the jury is still out on the usefulness of geo-engineering proposals.

But he sees a value to them: The very fact that such ideas are being proposed and research is underway means that global warming theorists are starting to "wake up to the facts."

"They are finally starting to get the message - which is that you really can't do much about global warming with carbon restrictions," Michaels said.

Even global warming advocates are starting to realize that we can't impact global climate change by imposing huge global taxes on carbon, or trying to ban all fossil fuels, he added.

The real debate over climate should center on geo-engineering, Michaels said.

"The technology to put a lot of stuff up into the stratosphere is probably not all that expensive," he said. "But I do know that we do not have the technologies to simply replace carbon-based fuels under any scenario of massive emission reductions. I would love to see that debate to go forward."

Michaels said the overall idea apparently originated with Soviet scientists in the 1970s, who were trying to change the climate over Northern Russia and reverse the flow of certain rivers.