If only that sort of testing had been done before we added two and a half trillion tons of CO2 to the atmosphere. Sadly, now we don't have a choice between mak

If only that sort of testing had been done before we added two and a half trillion tons of CO2 to the atmosphere. Sadly, now we don't have a choice between making a massive change or making no change. We just have a choice between leaving one change in place that we know is massively harmful, or using another method to reverse that change.