Chapter 3: COASTAL ZONES AND OCEANS

This chapter provides a useful compilation of the potential impacts of sea level rise in coastal zones throughout the world, with emphasis on the countries likely to be most affected. It summarizes strategies which have been proposed for anticipatory action and adaptation.

Summary

The chapter begins by describing present and expected future problems in coastal areas which are occurring regardless of climate change, including population growth, overfishing, declining wetlands, rapid industrialization and associated pollution, and increased tourism. It describes past impacts of water level changes in the Great Salt Lake, Lake Michigan, and the Caspian Sea and the often short-sighted human responses to those changes. It then draws on a large number of studies of countries that are particularly vulnerable to rises in sea level to assess societal vulnerability to global climate change. (Some of the studies are based on a hypothetical 1-meter rise in sea level, while others do not specify a particular water level change.)

Loss of land surface is a major impact of sea level rise. Some small island nations and delta areas would lose a large proportion of their populated or productive area in the event of a 1-meter rise in sea level. Particularly vulnerable nations include The Maldives, the Kiribati Islands, the Seychelles, Bangladesh, Egypt, China, and Nigeria. Rising sea levels would lead to displacement of large numbers of people from their homes and loss of agricultural production. Loss of wetlands would impact coastal fisheries, loss of beaches would undermine economies based on tourism. Of the world's 20 largest cities, 13 are in coastal locations. The protection of cities is expected to be a major cost associated with accelerated sea level rise.

Although economic losses are cited in many of the examples, no attempt is made to summarize the overall impact of sea level rise in economic terms. The authors find few reliable estimates of the value at risk, and they point out that present methods of valuing environmental goods and services are inadequate. The estimates that are mentioned, however, suggest potentially enormous losses or protection costs to prevent inundation and erosion in developed areas (urban, agricultural and tourist areas and coastal infrastructure).

A method of vulnerability analysis for coastal areas, defined by the IPCC Coastal Zone Management Subgroup, is summarized. The possible responses to rising sea levels are retreat (relocation), accomodation (adapting to changed conditions), or protection (building barriers to prevent changes to existing land uses). In small island nations and densely populated areas, retreat may not be an option. While protection has been implemented for many years in developed countries, notably the Netherlands, it would be prohibitively expensive for underdeveloped countries. Increased international conflict is likely in the event of large-scale relocation of people.

The authors emphasize, "Sea level rise exacerbates existing problems, rather than creating fundamentally new problems." They recommend the Integrated Coastal Zone Management approach for sustainable management of coastal areas--with or without global climate change and sea level rise. Multiple response strategies are needed, modified for different cultures and conditions. Adaptation is a key complement to any strategy of reducing the accumulation of greenhouse gases.

Strengths

This chapter summarizes a large body of existing research on the impacts of sea level rise in coastal zones in many of the most vulnerable countries of the world. It presents possible adaptation strategies and some of the limits on adaptation potential. This summary would be a useful starting point for researchers and policy makers interested in evaluating the potential impacts of climate change in coastal areas and assessing the possibilities for adaptation to rising sea levels in a variety of cultural and economic settings.

Weaknesses

The chapter is unnecessarily long and in need of rigorous editing. There are many typographical errors. The first 20 pages are not well organized, appearing to be the notes of many contributors pasted together with little attempt at integration. Much of the concluding section ("The challenges ahead in a climate-changed world") applies to all kinds of environmental change and may replicate material in other volumes.

The scope of this chapter is much more limited than its title ("Coastal Zones and Oceans") would imply. It focuses almost entirely on the impacts of sea level rise on coastal zones. Sea level rise deserves a strong emphasis because of its large potential impact in the event of global warming and the large amount of research attention it has received. It is unfortunate, however, that other potential effects of changing ocean temperatures have not been discussed. For example, changes in the habitat and range of marine organisms are observed during strong ENSO events, suggesting that entire marine ecosystems are likely to be disrupted in a warmer global ocean. In addition, changes in ocean currents could significantly change world weather patterns. The potential effects of global climate change on the oceans, beyond the coastal zones, appear to have been overlooked in this 4-volume work.


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