Uh oh. Top (former) UN Climate officials (Costa Rican diplomats with no scientific background) are "calculating" that if we don't stop emitting carbon dioxide by 2020 the earth is doomed! That's right: three years left to save the planet! Or is that 50 days? 96 months? Or were we doomed 5 years ago? Or was that 17 years ago? 4 days from now?…