Technology to remove CO2 from the atmosphere has been progressing over the past few years, and if we have the political and economic willpower born from a stark confrontation with reality, we might yet be able accomplish what is needed to drop atmospheric CO2 levels at a fast enough rate to begin to cool the Earth and halt further Arctic thaw. One thing is clear - a halt to all human CO2 emissions is not enough to halt climate change at this late date. Dropping CO2 levels by its natural absorption into the oceans and land plants and soil, will only keep temperatures constant - and constant temperatures will not halt the thawing carbon release from the Arctic. We need more. Klaus Lackner appears to be the lead scientist in the effort to devise the most economical way to pull CO2 from the atmosphere.
Nova Science Now 12 min video on Lackner's Resin method
An interview in 2012 with Klaus Lackner, on CityAtlas, and a shorter version here with some figures on impacting global CO2 emissions
Columbia U; Lackner publications
Yale Environment 360 op/ed on Lackner's idea
APS evaluation of CO2 capture from the atmosphere and brief summary
Wikipedia on Carbon Removal from the Atmosphere, including artificial trees
Literature Review on atmospheric CO2 capture - Fabian (MIT) 2012
Scientific American article on CO2 capture from the Atmosphere (May 2013)
Creating Calcium Carbonate from CO2 from steel slag. Can it be applied to the atmosphere? If all steel slag went through this process globally, you'd sequester roughly 30 million tons of CO2 per year. Nice, but it's still only 1/1000 of what we emit)
Pilot Industrial Plant being built, using atmospheric CO2 to make carbonate bricks (2014)
Creating Magnesite to Sequester CO2, at low temp. Not clear the reaction rate can be improved, however.
The Rau process for CO2 capture, (Rau et al. 2013) with promise to produce alkalizing bicarbonate suitable for the oceans as well as atmospheric CO2 capture. Cost ~$200/ton if neglect economic value of some chemical products produced (given we need to pull FAR more out than we can make use of).