By Mary Hoff

Klaus Lackner has a picture of the future in his mind, and it looks something like this: 100 million semi-trailer-size boxes, each filled with a beige fabric configured into what looks like shag carpet to maximize surface area. Each box draws in air as though it were breathing. As it does, the fabric absorbs carbon dioxide, which it later releases in concentrated form to be made into concrete or plastic or piped far underground, effectively cancelling its ability to contribute to climate change.

Though the technology is not yet operational, it's "at the verge of moving out of the laboratory, so we can show how it works on a small scale," said Lackner, director of the Center for Negative Carbon Emissions at Arizona State University. Once he has all the kinks worked out, he figured that, combined, the network of boxes could capture perhaps 100 million metric tons (110 million tons) of CO2 per day at a cost of $30 per ton—making a discernible dent in the climate-disrupting overabundance of CO2 that has built up in the air since humans began burning fossil fuels in earnest 150 years ago.