Current atmospheric CO2 levels are not unprecedented when compared to levels found throughout Earth's full geological record.
NOT BSTOTAL BS
HARDLY BS — Verdict: Mostly True
Verified by Lenz ·
The Short Version
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.
Caveats
Current CO2 levels (~422 ppm) are unprecedented in the last 14–23 million years — the timeframe relevant to modern ecosystems, species, and climate systems. The claim's 'full geological record' framing obscures this.
The rate of CO2 increase today is approximately 100 times faster than any previous natural rise, a critical distinction the claim entirely ignores by focusing only on absolute levels.
Deep-time CO2 estimates used to support the 'not unprecedented' framing carry error bars exceeding ±500 ppm, making precise comparisons against today's accurately measured levels scientifically tenuous.