Most methods of combating climate change focus on eliminating greenhouse gas emissions on the front end–whether it be through greater efficiency or increased use of alternative energy.
But some scientists are developing ways to reduce the amount of carbon dioxide once it’s already in the atmosphere.
From the Los Angeles Times:
Here’s a simple solution to global warming: vacuum carbon dioxide out of the air.
Klaus Lackner, a physicist at Columbia University, said placing enough carbon filters around the planet could reel the world’s atmosphere back toward the 18th century, like a climatic time machine.
After a decade of work, his shower-sized prototype whirs away inside a Tucson warehouse, each day capturing about 10 pounds of the heat-trapping greenhouse gas as air wafts through it.
Only a few billion tons to go.
Though the device works, it doesn’t sound very practical:
In the battle against global warming, technology has long been seen as the ultimate savior, but Lackner’s machine is a clunky reminder of how distant that dream is.
He estimates that sucking up the current stream of emissions would require about 67 million boxcar-sized filters at a cost of trillions of dollars a year.
The orchards of filters would have to be powered by complexes of new nuclear plants, dams, solar farms or other clean-energy sources to avoid adding more pollution to the atmosphere.
The LA Times has a nice picture to give the reader a sense of what your average 22nd century “CO2-Buster” farm might look like:
By Professor Lackner’s estimates, to eliminate the necessary amount of CO2 “would require spreading out his machines over a land area the size of Arizona.”
The U.S. Climate Action Partnership, a coalition of 26 companies and environmental groups who support action to fight climate change, came out to reiterate their 
