AGCI Session I: Natural Hazards and Global Change

Session Chairs: Louis Walter and E. L. Quarantelli - July 10 to 20, 1996

Oscar Huh

On natural disasters and coastal communities

An estimated 50 percent of the world's population lives along the coastal fringe of the land masses and this is expected to increase to 75 percent in the next century. A progressive increase in coastal environmental hazards is due to:

1 a population explosion of new residents and visitors, uninitiated to the realities of coastal environments, particularly the infrequent but catastrophic disasters;

2 deterioration of natural environmental buffers: erosion of dunes and beaches, collapses of cliffs, and depletion of fresh water aquifers;

3 expanding organic and pollution loading of the environment, particularly air and water, as a consequence of high density living and an industrial culture.

The global warming trend, and the expected continuation of rising sea levels that come with it, promises to exacerbate the problems of coastal communities. Sea level rise will have considerable impact on people, coastal structures, socio-economic systems, and ecosystems, especially in low -lying coastal areas already subject to erosion and subsidence. Millions of people, in particular those in developing nations with the least developed technologies and sometimes a total lack of financial resources will face a serious threat from rising sea levels.

Of all inhabited coastal environments around the globe, coastal wetlands and barrier islands are most vulnerable. Of particular concern are the developments on the great delta complexes of the world, including the Nile, Yangtze, Yellow, Mississippi, Ganges, Indus, Volga, and Irrawaddy. Architecturally, deltas are complex and fragile assemblages of marshy wetlands, barrier islands, shoals, channels, swamps, estuaries, river mouth bars, tidal flats, tidal ridges, bays, and natural levees. Many deltas are the sites of major coastal cities and are particularly subject to natural disasters including floods from the landward side and storm surges, extreme wave action and storm winds from the seaward side.

Land use zoning is critical, and should be based on environmental realities. For example, barrier islands, which may metaphorically be considered slow or episodically flowing rivers of sand, are quite unsuitable for permanent dwellings and should be zoned "no development" or "disposable development," with the economic or private enterprise charged with self maintenance and damage recovery without public support.

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