In this month’s environmental outlook, a look at rising sea levels and what’s at stake. Whether it’s caused by natural variability or human activity, the fact remains that sea levels are rising. The U.S. Geological Survey recently estimated that the Eastern Seaboard -- coined a "hotspot" by scientists -- will rise to four feet by 2100. A separate study by the National Research Council says ocean levels on the California coast could rise by three feet by the end of the century. Diane and her guests look at the causes and consequences of rising sea levels.