 it is our responsibility to clean it up for future generations.
Efforts to achieve this goal have focussed mostly, thus far, on capturing CO2 and sequestering it at the source of its production. A group of the world’s leading geoscientists, physicists, and climate scientists which convened at my institution earlier this year, and a similar group assembled independently at Oxford University this week, both came to the same conclusion: a more effective global strategy would be to remove carbon dioxide directly from the atmosphere. Remarkably, this sensible and direct approach has received almost no R. & D. support to date, compared to the tens of billions of dollars devoted to increasing fossil-fuel production. (For more, see Michael Specter’s piece in the magazine, from 2012, on geoengineering and climate change.)
Direct-air capture—deliberate extraction of CO2 from our atmosphere using empirically proven technologies—may turn out to be more expensive than carbon capture at the emission source, but it has several important possible advantages. It doesn’t have to be close to a hundred per cent efficient; it can be usefully done by a single country, or a “coalition of the willing”; and units could be deployed away from population centers in dry wastelands located above geologic strata suitable for storage of the captured CO2. Finally, because air capture is independent of the source of the CO2, direct-air capture would not have an impact upon “economic competitiveness,” a buzz term for many who now claim that the potential economic costs of energy transitions argue against changing the status quo.
Other supposed geoengineering solutions, including injecting other materials into our atmosphere, have been proposed to moderate the effects of anthropogenic climate change. They, however, treat symptoms, not the disease, and come with huge uncertainties associated with their possible impacts.
Whatever approach we may take to try to achieve a sustainable CO2 level in the atmosphere will require bold and dramatic initiatives. However, both the First World and the developing world have already shown an unwillingness to make dramatic reductions in carbon burning. Other strategies must therefore be explored.
As the I.P.C.C. report underscores, the climate emergency we face in this century is real. If social, political, and economic stresses mean that the world will not likely make the reductions necessary to avoid this emergency by mid-century, we need to explore every other possible technical means to do so. Carbon capture from the atmosphere may not be practical in the end. But exploring possibilities like it with the same kind energy that we are devoting to extracting fossil fuels should be an ethical global imperative, given everything we now know about humanity’s impact on our climate.
Lawrence Krauss is the Director of the Origins Project at Arizona State University, which recently sponsored a high-level workshop on climate change. He is also Chair of the Board of Sponsors of the Bulletin of the Atomic Scientists.
Photograph by Horacio Salinas.