http://www.sciencedaily.com/releases/2008/09/080911150048.htm

Normally, discussion about climate change and global warming generates images of ice melting. As glaciers disappear, hurricanes surge and tides rise, warming is observed through various examples of hotter water. But as scientists have studied in Antarctica, ice that remains intact is the key to many understandings of what is occurring to the Earth's atmosphere. The ice filled region of the South Pole contains ice cores, which are accumulations of ice and snow over a period of several years. Within the ice cores is relevant information that indicates the levels of important greenhouse gases with each time in history. Scientists have been using ice cores to analyze the global carbon cycle and climate for 70,000 years and have found more evidence to link climate change to increased carbon dioxide levels.

In the last Ice Age, as during most of Earth's history, levels of carbon dioxide and climate change are intimately linked. Carbon dioxide tends to rise when climate warms, and the higher levels of carbon dioxide magnify the warming, Brook said. These natural cycles provide a "fingerprint" of how the carbon cycle responds to climate change.

In contrast to the relatively low levels of carbon dioxide in the Ice Age, the burning of fossil fuels since the Industrial Revolution has led to levels of greenhouse gases that by comparison are off the charts. The level of atmospheric carbon dioxide today is about 385 parts per million, or more than double that of some of the lower levels during the Ice Age. These changes have taken place at a speed and magnitude that has not occurred in hundreds of thousands of years, if not longer. Past studies of ice cores have suggested that Earth's temperature can sometimes change amazingly fast, warming as much as 15 degrees in some regions within a couple of decades.

While the ice cores are not melting, they are providing alarming evidence that the present levels of greenhouse gases are troubling. With these observed correlations, scientists have further proof that their predictions of a warming climate are correct. By their estimations, it appears that a continuously hotter Earth is inevitable if nothing is done to reduce the climbing levels of carbon dioxide.

Science Daily; September 15, 2008

Submitted by K. Rutherford