It's a tidy answer to global warming

But some scientists say that the potential of such ideas cannot be ignored given the world's political paralysis on controlling emissions and its myopic addiction to cheap and dirty coal.

"There are not that many alternatives," Lackner said.

The attraction of a technological silver bullet lies in the failure of the world to solve global warming through the obvious solution: reducing emissions.

The 1997 Kyoto accords were supposed to bring the world together to address the problem, but the two biggest polluters, the United States and China, have refused to cap their emissions, and Europe is failing to meet even its modest targets.

Worldwide annual emissions of carbon dioxide -- the main culprit in global warming -- have climbed 28% over the last decade, according to the U.S. Department of Energy. The rise has been largely driven by industrializing countries, such as China and India, which argue that they have the right to exploit their coal reserves to catch up with the West.

It is clear that cheap energy is a drug that civilization will not give up. But big technological solutions could allow society to keep its drug.

Among the options, carbon filtering is the most direct and best understood. If industrialization is a process of transferring carbon stored in the earth to the atmosphere, filtering seeks to put it back.

The technology is decades old. Bottled oxygen used in hospitals started out as plain air before nitrogen, carbon dioxide and other gases were filtered out. Space capsules and submarines extract carbon dioxide to maintain breathable air for crew members.

The process for removing atmospheric carbon involves putting one compound, usually a hydroxide, in contact with the air, setting off a reaction that grabs CO2 and incorporates its carbon atoms into a carbonate compound.

Then, in a reaction that requires a large input of heat, the carbonate compound is broken apart, reconstituting and trapping the carbon dioxide.

Researchers propose pumping the captured CO2 into the ground, a practice already used to increase the pressure in oil wells. Geologists say there is room in subterranean rock formations to lock it away forever.

The beauty of carbon capture is that it scrubs the planet without intruding on it, unlike artificial volcanoes and sun reflectors, which could cause enormous planetary damage in the form of acid rain or giant shadows that stunt crops.