About Sea Level Rise
Increase in Earth's global temperature is causing an increase in sea level. There are two reasons for this accelerated rise in sea level. First, as Earth warms, the ocean absorbs some of the heat from the atmosphere and as it warms, the seawater expands. A greater volume of ocean water due to thermal expansion casuses a rise in sea level. Second, rising temperatures are causing ice and snow on land to melt, thereby increasing the amount of water in the oceans. (Only melting of ice and snow that are on land will increase sea level. The melting of floating ice will not affect sea level.)
Throughout Earth history there have been periods of glaciation followed by warming trends in which the glaciers retreated towards higher latitudes and higher altitudes. At present, glaciers throughout the world are retreating and the amount of snow and ice at the poles is shrinking. The present interglacial warm period began about 14,000 years ago. At that time sea levels were about 75 to 100 meters lower than they are today. The sea level rose rapidly (up to 1 meter per century) as massive amounts of snow and ice melted. Today the rate of sea level rise is much lower at 15-17 centimeters per century. However, the rate of sea level rise is increasing as the rate of global warming increases. An accelerated rate of sea level rise would inundate coastal wetlands and lowlands, increase the rate of shoreline erosion, cause more coastal flooding, raise water tables, threaten coastal structures, and increase the salinity of rivers, bays and aquifers.