Avery, "Unstoppable Global Warming: Every 1,500 Years" (Rowman & Littlefield, 2007)</ref> Though, it must be said, that no scientist denies that CO<sub>2</sub> has lagged behind temperature at certain times in Earth's history. They maintain this doesn't negate in any way CO<sub>2</sub> influence on temperature. It merely means it wasnt a first cause of temperature increase at particular times in Earths distance history.."<ref>What the lag of CO<sub>2</sub> behind temperature in ice cores tell us about global warming | Avery, "Unstoppable Global Warming: Every 1,500 Years" (Rowman & Littlefield, 2007)</ref> Though, it must be said, that no scientist denies that CO<sub>2</sub> has lagged behind temperature at certain times in Earth's history. They maintain this doesn't negate in any way CO<sub>2</sub> influence on temperature. It merely means it wasnt a first cause of temperature increase at particular times in Earths distance history.."<ref>What the lag of CO<sub>2</sub> behind temperature in ice cores tell us about global warming |