Atmospheric scientists twitter --
1) How many gigatons of CO2 is 415 ppm?
2a) How much energy (in joules) would be needed to break up enough CO2 to reduce the concentration to 300 ppm?
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2b) Does the world currently generate enough renewable energy such that if all the energy went to scrubbing CO2 in the atmosphere, that we could keep the Keeling curve flat at our present rate of CO2 emissions?