Ice cores reveal that CO2 levels rise and fall hundreds of years after temperatures changeIn 1985, ice cores extracted from Greenland revealed temperatures and CO2 levels going back 150,000 years. Temperature and CO2 seemed locked together. It was a turning point—the “greenhouse effect” captured attention. But in 1999 it became clear carbon rose and fell after temperatures did. By 2003 we had better data showing the lag was 800 ± 200 years. CO2 was in the back seat.AGW replies: There is roughly an 800-year lag. But even if CO2 doesn’t start the warming trend, it amplifies it.Skeptics say: If CO2...