The Carbon Cycle Sharon Sample 03.13.01 The concentration of carbon dioxide in the atmosphere has changed in the past hundred years. Before the Industrial Revolution (prior to the 19th Century), carbon dioxide levels stayed nearly stable for thousands of years. Since human beings developed a dependence on fossil-fuels, the amount of atmospheric carbon dioxide has increased dramatically. This increase means that less long- wavelength energy (like heat) emitted from the Earth can escape to space. Many scientists believe this can lead to a gradual warming of the Earth, but others believe that different factors counteract this warming effect. For example, cloud cover reflects sunlight before it ever reaches the Earth, thus reducing the amount of sunlight that reaches the Earth's surface. Studying these processes is difficult, because they are complicated, but ocean color information is an important tool used by scientists to try to find what changes are occurring, and how they may affect us. National Atmospherica and Space Administration (NASA)  Earth Science Enterprise  kids.earth.nasa.gov ©2001 The Aurora Collection, Inc. All Rights Reserved. Site Development by: Interactive Multimedia. Inc.