Both casual relationships are operative at all times: In the 19th and 20th centuries, the temperature - driving CO2 causal relationship
amplified the original temperature effect, as one
of several
factors leading to a net positive feedback on temperature due to CO2 increase, and a climate sensitivity
of about 3C for a doubling
of CO2 — a
number verified multiple times
by calculation from proxy data from multiple epochs in Earths prehistoric past.