As another international climate conference begins in Bonn, Germany, today, the world continues to warm and the human role grows ever more clear, as does the inability to reach meaningful agreements to slow emissions. One possible solution is scientists altering the atmosphere and cooling the planet with technology. But would that be the good news or the bad news? Some environmentalists say a geoengineering 'fix' might be worse than doing nothing. We're already messing with the atmosphere, and it hasn't worked out very well. Even research advocates seem afraid of the idea. But things are very likely going to get worse, and a 'Plan B' might look a lot better a couple of decades from now. We should start testing ideas now.