Cement and pinot noir were among the highlights of the AGU Joint Assembly in Toronto Tuesday.
Sequestration of carbon dioxide, that is, pulling it out of the air and storing it where it cannot affect climate as a greenhouse gas, is a quest that engages many scientists and engineers. Proposals have been made to store CO2 deep in the ocean and in depleted mines far underground. Soon, though, you may be able to walk on sequestered CO2, says Sidney Omelon, a chemical and materials engineer with Calera Corporation, a California start-up.
The purpose of a project under study and described in Omelon’s Joint Assembly poster Tuesday is to capture CO2 from concentrated sources, such as emissions from power plants. Step one is to channel the gas into an aqueous environment, in order to precipitate carbonate minerals. The novel part is what happens next. Calera is developing a process to incorporate this precipitate into the built environment, specifically in concrete used for street paving and buildings.
Cement, a key ingredient of concrete, is an ideal substance into which the precipitate can be added, Omelon said in an interview. She does not know of any other comparable projects. Surprisingly, in her view, it hasn’t been tried until now. “Honestly, I can’t believe no one [else] thought of it first,” she said.
Calera is also looking into using captured CO2 in aggregate, another key component of concrete. Even when concrete structures eventually crumble, the material itself would remain stable, Omelon said, and the CO2 would not escape to the atmosphere.
We are looking at CO2 as a resource, not just as a pollutant, Omelon concluded. “I think if we just turn our brains to this, we can do some really useful things with carbonate minerals and also just try and reduce our general energy consumption, so that we don’t emit as much CO2.”
Returning to the topic of regional impacts of climate change, covered in yesterday’s blog entry, I was intrigued by a poster that wasn’t posted today, although its abstract was published on the meeting’s Web site. Titled “Vulnerability of High-Quality Winegrowing to Climate Change in California,” it was listed as “withdrawn.” The author, Kimberly Nicholas Cahill of the University of California in Davis, said in response to my e-mailed query that she could not come to Toronto for logistical reasons and that the research and abstract were still valid.
So, what is in store for California’s top pinot noirs, the subject of Cahill’s study? Ideal growing conditions involve, she says, cool temperatures in fall the year before harvest, warm temperatures from budburst to bloom, and then cool temperatures again from bloom to the time grapes turn from green to their mature red color. Climate change can definitely affect this cycle, and winemakers are concerned, says Cahill.
Still, the industry’s adaptive responses are at this point highly individual, Cahill says. Her study concludes that in practice, successful adaptation must also include “proactive and coordinated community responses,” which she says are just beginning to develop. Further research in the vineyards is also necessary, of course!
Harvey Leifert is a freelance science writer