So if this climate-change business gets really serious, can't we just deploy some geo-engineering marvel to block the sun, cool the oceans, or just suck carbon out of the air? Today at Wonkbook, Brad Plumer gives a nice primer of climate-manipulation proposals:
We could [plant] more trees, although there’s only so much land to go around (especially as demand for cropland grows). We could try to fertilize the ocean with iron to promote the growth of plankton, which absorb CO2. We could try to speed up natural processes that take CO2 out of the air, such as rock weathering. Or someone could just invent a machine to scoop up the carbon directly.
If only! Well here comes Tom Murphy, an associate professor of physics at UC San Diego, to spread a big wet blanket on that notion. In "Putting the carbon emissions genie back in the bottle," Murphy calculates that each American produces roughly their body weight in CO2 each day. That's about 25 square meters of pure carbon dioxide--enough to fill the red cube pictured above. The larger pink cube below is how much CO2 that average person produces over 40-years. If you "sequestered" that CO2 by binding it into limestone, just the daily dose would produce a brick weighing 115 kg--about 250 pounds. Squirreling away the 40-year amount would produce a block 8.6 meters on a side--that's the gray cube.
Where could we stash these giant bricks of limestone? They’re kind-of an eyesore in the back yard. In total, we’re talking about a Mount Everest-scale cube 10 km on a side. Wait a minute—didn’t we make a hole in the ground to extract the CaO in the first place? Yes, but this hole is only 45 percent the volume of the ultimate value-added brick. Maybe that’s half the battle, but half of a gigantic volume is still a gigantic volume. The point is not that we do not have enough room on the planet to accommodate these fantasy bricks of limestone, but just that they are not inconsequential things, at a personal scale.
There's much more--including a discussion of what a CO2 air scrubber might look like--but for that you'll have to read Murphy's engaging post. It provides a much needed tonic to all the talk of "carbon capture and sequestration." It also brings to mind what English philosopher J.L. Austin said in How to Do Things With Words: "There are easier ways to kill a cat than drowning it in butter." Rather than finding a place to put our personal 8.6-meter cubes of carbon, it would be easier all around to just get Beyond Coal and Beyond Oil.