Predictions regarding sea-level rise are one of the most controversial aspects in climate science, with estimates ranging from a few inches to several meters. Dramatic images of the Statute of Liberty barely peeking above the waterline aside, there is little doubt that there will be a rise in the overall sea level over the coming century.
Water will expand as ocean temperatures rise, and the melting of the polar ice caps will contribute to the overall volume of water. But the rise is not uniform across all oceans, and the mechanisms that contribute to the rise are not yet clearly understood, casting doubt on all projections.
Sea levels have climbed 400 ft. (130 m.) in the past 18,000 years. For 3,000 years, the rate of that rise was .004-.008 in. (0.1-0.2 mm.) per year. Beginning in 1900, it climbed to .04-.08 in. (1-2 mm.) per year, and in 1993 accelerated to approximately .12 in. (3 mm.) per year (although it is not yet clear if this is a cyclical variance or part of an overall trend). Were these rates to hold steady,
this would correspond to a rise of 11-13 in. (280-340 mm.) by 2100. However, some climate models, particularly those who look at the partial or complete melting of the Greenland Ice Sheet, indicate a more dramatic rise of about 3 ft. (1 m.), a rise that would, among other things, swamp most of the cities along the United States' densely populated eastern seaboard.
Rising water levels put the 634 million people who live within 30 ft. (9 m.) of sea level at risk for higher storm surges, coastal erosion, loss of agricultural and aquacultural land, loss of tourism, and a decline in soil and groundwater quality. Several small islands in the Pacific and Indian oceans, most notably the island nation of Tuvalu and the Maldives, are already seeing anomalous flooding and higher tides. Residents of these islands may be the first in a long line of "climate refugees" to come.
Was this article helpful?