Researchers in the National Center for Atmospheric Research's Climate and Global Dynamics Division are addressing a global rise in sea level of about 10-20 centimeters (4-8 inches) during the 20th century. This seems to be a result of the enhanced greenhouse effect, a general warming trend caused by the increase of carbon dioxide and other trace gases in the atmosphere. The melting of land-based ice sheets and glaciers, and the expansion of oceans due to warming, are factors in the sea-level rise. Very large rises in sea level would eventually cause flooding in major coastal cities and large parts of low-lying countries.
