Neither emissions reduction nor simple ocean fertilization will do much for the U.S. before we reach the 2°C (3.6°F) overheating frontier. That happens about 2028 when today’s toddlers finish high school.
But there’s still a class of climate fix that is analogous to plowing under a cover crop. If we immediately bury the new green stuff, we get a big boost in the efficiency of cleaning up excess carbon.
On land, one can grow extra greenery, then harvest and bury it somewhere that will keep its eventual carbon dioxide from making its way back into the circulating air. However, this too needs a lot of new growing space and water resources (and you have to keep it from burning in a time of worse droughts and higher winds)–all at a time when expanding human populations will contest such land and water use.
Not likely. What’s left, given that massive ocean fertilization looks unlikely to settle out enough carbon into the ocean depths? It turns out that we can augment settling out the new greenery with pumping it down.
In the ocean surface layer, three-quarters of the new green turns back into carbon dioxide within a week or two via respiration or rotting. Fortunately, we can use push-pull pumps to fertilize and then sink the new algae within days so that carbon dioxide production instead happens in the depths.
There are even cheaper ways to do push-pull pumps but an easy-to-visualize method uses floating windmills. Long pipes hang 15 to 30 stories down into the slowly moving depths. One windmill operates traditionally, pulling deep water up to the surface. The nutrients in this near-freezing water create a sustained bloom of algae.
The other windmill pump pushes the enriched surface water down to where it cannot resurface for millennia. Pumping down stores the carbon in the brand-new algae as well as canceling out whatever carbon dioxide was also pulled up. Even more importantly, it sinks the hundred-fold larger amounts of carbon from the feces and cell debris that would never sink unaided.
This “dissolved organic carbon” ordinarily becomes carbon dioxide within a week or two and then escapes into the air as winds stir the surface layer. Stashing it as well is the second big step up in efficiency achieved by push-pull pumps.
Once pumped down, the excess carbon takes 1,000 years to begin slowly resurfacing elsewhere as carbon dioxide. Its re-emergence is then at a rate that is only one percent of current emissions. Even forest management could counter such a slow rate, if an advanced technology could not.
Green-water plantations might require less than one percent of the ocean surface (that’s about the surface area of the Caribbean). Stringing them out above the edge of the continental shelf would allow currents and dilution to prevent the formation of anoxic dead zones.
The resulting acidification, which would be a major problem near the ocean surface, is only a minor problem when the new acidity is diluted fifty times in the depths (98 percent of the ocean).
So there is still likely to be a class of climate fixes that involve mimicking the ocean’s natural processes of upwelling and downwelling.
Even this intentionally low-tech example appears to be cheap enough, big enough, fast enough, and sufficiently secure against backsliding to do the job in twenty years. But my back-of-the-envelope estimate merely outlines the ballpark in which we are forced to play. It needs to be refined or replaced by real experts.
To do the planning job right is going to take a “Second Manhattan Project” of various experts to design cleanup candidates and evaluate their side effects. House them at Los Alamos and let the Army buy them what they need with wartime priorities. To field test their plantation designs, let them instrument the many abandoned oil platforms in the Gulf of Mexico. Then quickly deploy the best designs, using the abilities of the offshore services industry.
Aim to accomplish all of this in the traditional three years. Ten years later, the cleanup job should be half done, and without all of the economic pain of a quick (and ineffective) shutdown of fossil fuel use.
Don't do it and we will, within that period, become angry with those politicians who were asleep at the wheel or helped spread the climate denial propaganda from the fossil fuel industry.
So the good news is that there is still an escape route open, if we act quickly enough. The bad news is that we have blown past most possible exits during the last forty years, without even noticing.
We must now think of the quick cleanup as a last-ditch effort to avoid a fortress world, one full of all Four Horsemen: starvation, epidemics, resource wars, and genocides.
William H. Calvin is a professor at the University of Washington’s School of Medicine in Seattle and the author of "The Great CO2 Cleanup: Backing Out of the Danger Zone" (ClimateBooks) and “Global Fever: How to Treat Climate Change” (University of Chicago Press). ©2013 W. H. Calvin. A more detailed proposal is at the MIT CoLab site for geoengineering: http://climatecolab.org/...
Fourth in a series of five climate repair diaries starting at "Is this the best we can do?" http://www.dailykos.com/...