The claim is technically accurate: multiple peer-reviewed studies confirm CO2 exceeded 1,000–2,000 ppm during earlier geological periods (e.g., Mesozoic, Eocene), well above today's ~422 ppm. However, the claim omits critical context. Current CO2 is the highest in at least 14 million years, the rate of increase is roughly 100 times faster than any known natural rise, and deep-time CO2 estimates carry large uncertainties (±500 ppm). The literal statement is defensible, but its framing can create a misleading impression that today's levels are unremarkable.