Recent reconstructions suggest CO2 concentrations may have ranged between 150 and 600 ppm (or more) throughout the last 4 million years. We routinely see screaming headlines such as CO2 in the Atmosphere Climbs to Highest Level in 4.5 Million Years or Carbon Dioxide Levels Reach Highest Point in Human History. However, these claims that modern … Continue reading Deliberately Alarmist ‘The Last Time CO2 Was This High’ Claims Are Rooted In Guesswork, Not Science