"Over the last few years, some of world’s brightest minds have become fascinated with a seemingly simple idea: easing the threat of climate change by pulling carbon dioxide out of the air.
The concept is entirely different from capturing and sequestering carbon dioxide from power plants and other big polluters before it enters the air. Rather, the aim would be to remove the gas from the planet’s ambient air, where it exists in low concentrations everywhere.
In 2007 the British billionaire Richard Branson and Al Gore, the former vice president, created a $25 million prize for the first creator of such a technology, and millions of dollars in venture capital have since flowed to start-up companies tackling the problem.
But a new study casts serious doubts on whether such efforts will ever yield an economically viable tool for fighting global warming. The study, released on Monday by the American Physical Society, the world’s largest group of physicists, finds that while removing carbon dioxide from ambient air is technically feasible, the cost is likely to remain prohibitively high."