In 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 that carbon dioxide 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.
Fallacy: false choice