Impact of sea‐level rise assessed

Abstract

Coastal erosion, flooding of low‐lying coastal areas, disruption of ecosystems, probable population relocation, and economic loss are some consequences of projected relative sea‐level rise. The term includes both the rise anticipated to result from global warming and other factors, and the rise from local tectonic subsidence. Some specific sites were discussed at the annual meeting of the American Association for the Advancement of Science, held in Washington, D.C., February 14–19.In comparing the New York City and eastern Mediterranean coasts, Victor Goldsmith of Hunter College, New York, presented a case for stabilization versus retreat of coastal areas, dependent on the geologic terrane and on the degree of development. The 578‐mile New York City coastline is considered “hard,” meaning some sort of cement structure, such as roads, jetties, or piers, separates the water from the coast. It is also an area of many beaches that are not natural, but that have been built up and maintained by the process of sand nourishment over the past 50 years. The Rockaway peninsula, for example, has received more than 12 million cubic yards of sand between 1926 and 1962 in response to the measured sea‐level rise of 30 cm in the last 100 years from downwarping of the wide continental shelf, said Goldsmith. Because land is highly developed and expensive in this area, retreat is not a practical option. Goldsmith suggests that the effects of on‐going sea‐level rise, at rates of about 1 foot per century, can be offset by continued hardening of the New York City coastline and beach nourishment where necessary.