Wampum

Le Monde has an interview with Edouard Bard on the subject of cooling the earth.
Summary:

1. doing anything, regardless of the consequences, gives the carbon industry political cover to simply keep dumping carbon into the atmosphere.
   
2. aerosol pollution -- dumping sulfur particles in the upper atmosphere to reflect solar radiation, à la volcanic eruptions, will result in both cooling and heating effects locally, that is, in more variation from current agricultural expectations.
3. nutriant pollution -- dumping iron particles in the upper ocean to stimulate phytoplankton, which absorb CO₂, will sequester CO₂ in benthic organic matter, however, bacterial decomposition of benthic organics will both result in hypoxic zones, aka "dead zones", and eventually the N₂O produced by bacterial oxidation of the organic matter, a greenhouse gas far worse than CO₂, will escape back into the atmosphere, and we don't yet know (a) how long the CO₂ benthic sequestration will last, or (b) how long until the N₂O benthic production is re-introduced into the atmosphere.
   

These proposals make wearing shiny clothes and decorating with mirrors appear quite attractive, if only for their lack of complex, obvious and inobvious, consequences.