During Earth's history, there have been periods where atmospheric carbon levels were significantly higher than they are now while the climate was much cooler.

Oct 31, 2026

Previously: During Earth's history, there have been periods where atmospheric carbon levels were significantly higher than they are now while the climate was much cooler. [Accurate]: Geological and paleoclimatic records indicate that during certain epochs of Earth's history, such as the Late Ordovician, atmospheric CO2 concentrations were higher than modern levels while the planet experienced glaciation. These periods are often influenced by other factors like solar luminosity, continental configuration, and orbital variations.

Now: During Earth's history, there have been periods where atmospheric carbon levels were significantly higher than they are now while the climate was much cooler. [Unverified]: Earth has experienced natural climate changes, and CO2 is not its only temperature driver. But Joe supplies no particular interval or temperature estimate for the stronger claim that much higher CO2 coincided with a globally much cooler world than today. Glaciation somewhere on Earth alone does not establish that global comparison. The original Ordovician example was not sourced sufficiently to settle it.

Do not treat the presence of ancient glaciers as proof of a lower global mean temperature than today.