June 2009      [HOME]     List of illustrations     BACK

Rising sea level in New York City: the tide gauge at the tip of Manhattan has measured an increase of roughly a quarter meter (ten inches) since 1920. In some places the sea is rising faster, in others slower or even sinking due to local effects. But the average of gauges in geologically stable locations around the world shows a steady rise of about 20 cm/century since the late 19th century. The effects of melting glaciers and ice sheets are hard to determine or to predict. But simple thermal expansion of seawater, due to the higher temperatures already observed, is bound by itself to cause a continuing, indeed accelerating, rise.

NASA Earth Observatory, based on data from the Goddard Institute for Space Studies.