Past CO2 levels were effectively proxies for temperature. That correlation is now broken. You can't correlate CO2 with temperature anymore.Because we know from direct measurements for the past 880,000 years, and proxies prior to that what the CO2 and CH4 levels were. You could try to look at scientific journals put out by Scientific Societies like the Geological Society of America and the American Geophysical Union. But, of course, you have to have a scientific vocabulary exceeding that of a third grader to read and understand the articles. Sorry about that.
What part of we are still below the peak temperature of previous interglacials do you not understand?