Based on the evidence from climate science research, here is my assessment of this claim:

Reasoning:

• Antarctic ice core records spanning approximately 800,000 years show that during natural glacial-interglacial cycles, temperature changes did indeed precede CO2 changes by roughly 600 to 1000 years¹².
• This phenomenon is well-established in paleoclimate science. The initial warming was triggered by orbital forcing (Milankovitch cycles - changes in Earth's tilt and orbit around the sun), which then caused CO2 to be released from warming oceans (as warmer water holds less dissolved CO2)²³.
• The released CO2 then acted as a feedback mechanism, amplifying the warming. In fact, approximately 90% of the global warming followed the CO2 increase, demonstrating that CO2 played a significant role in amplifying the initial orbital forcing².
• A 1990 paper by Claude Lorius (co-authored by James Hansen) actually predicted that CO2 would lag temperature during these transitions, before ice core records were accurate enough to confirm this lag².
• Recent studies suggest the lag may be considerably smaller or even difficult to detect precisely due to challenges in dating ice cores, as there is a delay between when snow falls (trapping air bubbles) and when it compresses into ice⁴.
• It is important to note that this historical relationship does not contradict current anthropogenic climate change, as today humans are adding CO2 to the atmosphere independently of natural orbital cycles³¹.

Overall validity: 95%

1. CO2 lags temperature - what does it mean? - Skeptical Science
2. CO2 lags temperature - what does it mean? - Skeptical Science
3. CO 2 lags temperature rises in ice core data
4. Explainer: How the rise and fall of CO2 levels influenced the ice ages