Humans have continuity built into their thinking, and this study will shock people. The Holocene's climate swings were a natural phenomenon. But during the past 200 years, the burning of coal, gasoline and other fossil fuels has added more than 80 ppm of carbon dioxide to the atmosphere. The total amount is now above 370 ppm and is expected to double in the 21st century. The 1990s are the warmest decade on record.
Many scientists fear that human activity is the driving force behind the warming.
White and other scientists said the group's analysis is plausible, but suspect it is too neat to be precisely accurate. It does not adequately reflect the complex interactions of oceans, forests and other ecological features in the carbon cycle, White said. We welcome your feedback. All rights reserved.