Even without any help, most of the carbon dioxide humans have emitted would eventually turn to stone, via a natural process known as chemical weathering. But “eventually” here means hundreds of thousands of years, and who has time to wait for nature? At Hellisheiði, Aradóttir and her colleagues were speeding up the chemical reactions by several orders of magnitude. A process that would ordinarily take millennia to unfold was being compressed into a matter of months.
