I myself have the gut feeling that large scale bioengineering would only initiate yet another cascade of unanticipated destructive side-effects. Your information has reinforced those notions, but it’s good to know where the issue stands these days.
Certainly possible, though my sense is that abating greenhouse gases is going to be such an enormous political problem that it’s best to attack it from as many different angles as possible. If geoengineering proves politically palatable, and if it looks to be plausible on a reasonable cost/benefit analysis, then I think it should be one of many avenues we pursue. But certainly, as Eli clearly said, not to the detriment of abating the production of the gases themselves.
To put it another way, I expect it will be politically impossible to abate greenhouse gas production to the extent necessary to avoid detrimental impacts of global warming. For one thing, with the chinese and indian economies growing rapidly, they will not be looking to decrease their production of CO2 anytime soon; indeed, it is politically inevitable that their production of CO2 will increase for the foreseeable future.
So although we may work very hard to abate CO2 production generally, we simply must also look to methods for soaking it up from the atmosphere, or for other methods of geoengineering, in the meanwhile. I’m speaking as a political realist here ...