So now Grist is reporting that geo-engineering is actually being seriously considered as remediation for GHG indsuced global climate change.

Does the rejuvenation of soil as a carbon sequestration mechanism constitute geo-engineering?  If it were acomplished globally with a wholesale shift from chemical ag to organic fertilizer from waste stream biomass it could be, and actually would remove enough GHG to equal other geo-engineering schemes.  Consider the elimination of nitrous oxide (300x the GHG effect of cO2) from chemical fertilizer and the reduction of methane (20x the GHG effect of CO2) emissions from chemical fertilizer run off bio-reacting with cellulosic biomass in soil and wetlands.

Natural prairie soil stores 1.8 tons of CO2 per acre per year.  Going organic with ag soil and restoring conservation land to its former sequestration rate might do it, actually reverse global climate change.

And the biogas produced through waste biomass digestion and organic fertilizer production could backup a 100% renewable grid, while offsetting 20 times the CO2 from the biogas energy production.

Overlooking the possibility of using wind/wave powered low cloud formation for not only reflectivity, but also  for rain and snowfall increase in strategic areas like glaciers, tundra, deserts, and ice caps, is a striking omission.  Think of deserts flooded with rainfall and greenery, turning all that CO2 into soil carbon sequestration potential via a huge increase in photosynthesis.  And consider the artic summer, with 24 hour sunlight, with an extra thick ice cap, tundra, and glacial cover of snow from low cloud formation during frigid winter.  That's huge reflectivity during the hottest solar absorption season in the most delicate climate for ice melt and feedback methane release.

The total potential is huge, and fuel less with wind/wave powered floating "ships" that can be directed to take advantage of weather paterns to maximize these effects of rain/snow fall.

I would rather see renewable energy backed by organic ag and biomass recycling as a fix, but if we are too late, the low cloud solution seems feasible and the lesser of geo-engineering evils.

I've got to point out though that mother nature most l;ikely will use geo-engineering as drought and ice melt sets in.  Land is rising in alaska as glaciers melt and the countervailing force of the weight of ice is removed and magma pressue pushes relentlessly upwards.  There are signs that volcanic activity will ocurr due to the loss of aqifers in drought and glacial mass.  Yellowstone's hot springs and geysers cool the rock capping the magma bubble, and the weight of the water hold the cap down.

When/if aquifer water evaporates from the area and is not replenished by rainfall will the supervolcano erupt?  Will that cause years (as in 1816) or deacdes with no summer, thus cooling the planet into a mini ice age?  And how many volcaones that are being suppressed by glacial and aquifer mass are ready to blow all around the world?