Post by aquaduct on Jan 15, 2022 20:52:45 GMT -5
I have been reading a little about this. This came up in Scientific American. August 2019 issue.
A Crazy-Sounding Climate Fix
We should convert methane, a more powerful greenhouse gas, into CO2 By Rob Jackson and Pep Canadell
Carbon dioxide in the atmosphere blew past 415 parts per million this past May. The last time levels were this high, two or three million years ago, the oceans rose tens of meters, something likely to happen again as Earth’s ice melts over the next 1,000 years.
To replace bad news with action, we need hope—a vision for restoring the atmosphere. Think about the Endangered Species Act: it does not stop at saving plants and animals from extinc- tion; it helps them recover. When we see gray whales breaching on their way to Alaska every spring, grizzly bears ambling across a Yellowstone meadow, bald eagles and peregrine falcons riding updrafts, we are celebrating a planet restored. Our goal for the atmosphere should be the same.
Rob Jackson chairs Stanford University’s Earth system science department and the Global Carbon Project.
Pep Canadell
is a staff scientist
at CSIRO in Australia and executive director of the Global Carbon Project.
As leaders of the Global Carbon Project, we have spent our careers working to reduce greenhouse gas pollution. Today we are making what may at first seem like a counterintuitive pro- posal: we want to increase carbon dioxide emissions temporar- ily to cleanse the atmosphere of a much more powerful green- house gas.
Stick with us here.
We are not saying increasing CO2 is a good thing in and of itself. The gas that concerns us is methane, which leaks from wells and pipelines; bubbles up when organic matter rots in
landfills and rice paddies; emerges from the digestive systems of cattle and from the manure piles they leave behind; and more. The good news about methane is that it remains in the atmo- sphere for a far shorter time than CO2 does. The bad news is that methane is vastly more efficient at trapping heat—more than 80 times more, in the first 20 years after its release—which makes it, pound for pound, a bigger problem than carbon.
We want to remove methane from the air and then use porous materials called zeolites to turn it into carbon dioxide. Zeolites can trap copper, iron and other metals that can act as catalysts to replace methane’s four hydrogen atoms with two oxygens. Because a methane molecule holds more energy than carbon dioxide, the reaction typically runs to completion if you can jump-start it. Furthermore, by releasing the carbon dioxide back into the air instead of capturing it, you make the process less expensive and lengthen the life of the zeolites.
Researchers around the world are already studying zeolites and other materials to convert methane to methanol, a valuable feedstock for the chemical industry. Making methanol is a halfway point in our reaction, tacking one oxygen atom onto each meth- ane molecule. No one seems to have considered finishing the job by making carbon dioxide in the same way because carbon diox- ide is not valuable like methanol. We should consider it now.
Another surprise about our proposal is that you could restore the atmosphere by removing “only” three billion met- ric tons of methane. Doing so would generate a few months’ worth of industrial carbon dioxide emissions but eliminate up to one sixth of overall warming. That is a good trade by any measure.
What we propose will not be easy to accomplish. Methane is uncommon: whereas the atmosphere cur- rently holds more than 400 molecules of carbon dioxide for every million molecules of air, methane accounts for only two or so out of a million. That makes pulling it from the atmosphere harder than keeping it from enter- ing in the first place. We will need other things to work as well. To give companies, governments and individu- als financial incentives to do this, there has to be a price on carbon or a policy mandate to pay for removing methane. We also need research on the large arrays needed to capture methane from air. And of course, we need to fix methane leaks and limit emissions from oth- er human sources. But we cannot eliminate those emis- sions entirely, so we would have to continue removing
methane from the atmosphere indefinitely.
Restoration of all the gases in the atmosphere to preindustri-
al levels may seem unlikely today, but we believe it will occur eventually. Such a goal provides a positive framework for change at a time when climate action is sorely needed. Stabilizing glob- al warming at 1.5 or two degrees Celsius is not enough. We need the planet to recover.
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10 Scientific American, August 2019
Illustration by Francesco Ciccolella
How much are they asking taxpayers to give them to do that?