Columbia University scientists say that technologies to extract carbon dioxide from the air will likely become a critical part of any strategy to stabilize the global climate and should not be abandoned because of high costs. Writing in the Proceedings of the National Academy of Sciences, the researchers from the university’s Earth Institute argue that the use of technologies to remove emissions at the source — such as at coal-powered plants — will not go far enough because they don’t address the transportation sector, which accounts for up to half of global CO2 emissions. In addition, the scientists say that the shift to renewable energy sources will likely not occur fast enough. Technologies that remove CO2 from the atmosphere on a large scale — such as forests of artificial trees or the use of absorbent liquids that extract CO2 — could help avert potentially dangerous warming. While the costs will likely be high at first, the paper said, they will come down as the technologies are more widely deployed. “The field of carbon sequestration as a community is too timid when it comes to new ideas,” said Klaus Lackner, lead author of the paper.