One of the most significant impacts of rising global temperatures will be melting of the polar ice on Greenland and Antarctica. These are known as continental ice packs, since the ice rests on underlying land. Their melt-water contributes to sea level rise, the same way adding another cube of ice to a full glass of soda will cause it to overflow.
One might predict sea level will rise evenly on all of the world’s coasts. But sea level rise is affected by other variables, including changes in coastal elevation and off shore currents. The coast of the northeastern U.S., say along the coast of Maine, is itself rising as it recovers from the weight of the continental glaciations 18000 years ago. Where the coast is rising, the relative impact of climate change on sea level is lower.
In the southeastern United States, the underlying coast is generally falling in elevation, so the impact of sea level rise from global warming is added to the background rate of change. A northward shift in the Gulf Stream has also contributed to exceptional rates of sea level rise from North Carolina to New Jersey.
Estimates of sea level during this century predict a rise of about 18”, with the high bets about twice that value. In the U.S., more than 18 million people are likely to be affected, and the cost to our economy may approach $300 billion each year—close to 6% of our gross domestic product. These are real costs of global climate change.
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Web Links
Yin and Godard (2013). Oceanic control of sea level rise patterns along the East coast of the United States. Geophysical Research Letters
Toon Haer et al. (2013). Relative sea level rise and the conterminous United States: Consequences of potential land inundation in terms of population at risk and GDP loss. Global Environmental Change, October 2013
William Nordhaus (2013). The Climate Casino. Yale University Press, New Haven.
Photo, taken on March 16, 2009, courtesy of Avery Studio via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.