Resource Insights: "In 1896 Svante Arrhenius, a Swedish chemist, was the first person to realize that human-created fossil fuel emissions might change the climate. He calculated that it would take 2,000 years to double the concentration of carbon dioxide in the atmosphere. The latest calculations suggest a doubling by 2050, only 154 years after Arrhenius' realization. The Hansen research also reminds us that the pace of warming is increasing: "[T]wo-thirds of the 0.9 degrees C global warming (since 1850) has occurred since 1975.""