[SunTzuWu]

It was a ringer because CO2 does not cause warming, it follows warming. That's why it's called a trailing proxy. A warm environment releases CO2 that is otherwise sequestered by nature.

[Little Pig]

My point precisely. The question was based on the (false) premise that CO2 causes warming in the atmosphere.

The jury’s still out on whether CO2 *contributes* to a warming process (cf Venus), but most real scientists don’t believe it causes warming, or even that anthropogenic warming (implied by the inclusion of CO2) exists.