claim: "The killer proof that CO2 does not drive climate is to be found during the Ordovician- Silurian and the Jurassic-Cretaceous periods when CO2 levels were greater than 4000 ppmv (parts per million by volume) and about 2000 ppmv respectively.
evidence: In 1985, agriculture made up 37.2% of Vietnam's GDP; in 2008, that number had declined to 18.5%.