Connonwealth Expert Group Oa Cliaatie Change and Sea-Level Rlee Fhe I^Plicatione of Sea Lev«L HBO F Or Island and Low-Lying Countries
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CONIDIVBALTH SBCRBTARI AT Connonwealth Expert Group oa Cliaatie Change and Sea-Level Rlee fhe I^plicatione of Sea Lev«l HBO f or Island and Low-lying Countries Janes Lewis Datun 1nternati onal 101 High Street Harshfield Viltshire -- ' ; SI14 8LT " - -1""J-- Telapbone 0225 _<fttti> 891426 T«lex 4662^ Karch 1988 COKTENTS Page 1 Introduction and Summary 1 2 Island variety 5 3 The sea and change to land and islands 9 4 Tropical cyclones and sea-surge 15 5 Island and coastline contexts 27 6 The effects of sea-level-rise 30 7 Vulnerability management 36 benefits and risks 36 - protective features 42 traditional knowledge 42 - project identification 43 construction management 43 - monitoring and survey 44 - migration and emigration 45 co-ordination 46 8 Preparedness measures 47 warnings 47 - physical structures 47 9 Regional initiatives for national strategies 49 - economic and financial implications 50 organisational and institutional arrangements 51 10 Relevance to other countries 52 Eeferences 53 F Tables Page Table 1 Commonwealth Member Island Countries, Associated Island States and Dependancies Table 2 Tropical cyclones in Conmonwealth Countries; 1977-1988 (Karen) 22 Table 3 The effects of sea level rise 34 Table 4 Adaptations for hazards associated with sea level rise, 40 Figures Figure 1 Distribution and location of islands at last glacial maxinum (18, 000 years BP) and today. Islands shown at present from north to south; Kiribati; Tuvalu; Rotuma; Vallis; Futuna; and Fiji 11 Figure 2 Changes in size, shape and distribution of islands in south-central Lau during the last 18,000 years 12 Figure 3 Funafuti Atoll, Tuvalu 14 Figure 4 Deltaic areas of India and Bangladesh 15 Figure 5 The breeding grounds of tropical cyclones 17 Figure 6 Track of the 1970 tropical cyclone, Bangladesh 19 Figure 7 Track of tropical cyclone (hurricane) "Bully" 1987 20 Figure 3 Track of tropical cyclone "Isaac" showing local times and barograph 24 Figure 9 'Uiha Island, Tonga, showing very approximate contour of 1.5 metres sea level rise (shaded area would then be below mean sea level). 32 Figure 10 The Koki Settlement in Port Moresby 38 1 Introduction a^ri! fitU!HHT~y Environmental perception and management appropriately recognise the impact that the activities and affairs of man have upon natural systems and processes. Environmental protection and conservation are now widely established to which ideally belongs hazard reduction, as an achieved harmony of activities with environments of a hazardous kind. Sea level rise might seem to reverse this perception of environment; man's impact being outclassed by environment's own potential impact upon hin. This however, has always been the case. Volcanic eruptions, earthquakes, fires and floods, as well as tropical cyclones, have frequently made manifest their often catastrophic forces - against which it has seemed, man Is powerless. In this context, hazards associated with sea level rise are in continuation of a status quo, not the commencement of a new regime. This is more particularly the case if current concern with regard to see level rise is considered appropriately in its longer-term context. Sea levels have fluctuated in the past as the result of both long-term and short-term phenomena; in the future they will surely continue to do so. The shortest time spans suggested for rise enough to bring severe inundation are sufficiently long to allow appropriate adjustment. Significantly, in most of the island countries where and upon whose behalf concern is greatest for the potential impact of sea level rise, there is considerable experience of adjustment to hazards; not only to the high winds, heavy rainfall and sea-surge associated with tropical cyclones, but also to volcanoes, earthquakes, fires, floods, and of severe reductions in rainfall. It is as part of these national and local contexts of hazard experience, that sea level rise should be considered. Knowledge and experience of environmental hazards generally, and of tropical cyclones in particular, will be the primary resource for addressing sea level rise and the problems and implications it brings. To a large extent therefore, sea level rise can be regarded certainly as hazardous, but no more hazardous in most already hazardous situations as anything else. Exceptions to this general view are those island countries where all islands are low-reef or atolls (eg Kiribati and Tuvalu) and/or those Commonwealth island countries where there has been minimal or extremely intermittent hazard experience. In most countries however, hazards are endemic and largely unchanging in their occurrence frequencies. What has changed is man's perception of himself in their context. First, by a growing misapprehension that man is more able to resist and to protect himself against hazards whilst knowingly or not, increasing his exposure. Second, this misapprehension, induced by large scale technology, is accompanied by an erosion of smaller scale and traditional adjustments that had created a greater harmony between man and hazards: and Third by an increasing erosion of understanding of environment and of man as one of its components. Pollution and ecological destruction may not be recognised as crucial until, in disaster, what has been destroyed would have been a protection or a survival resource, Rising sea levels potentially affect directly all countries except the landlocked; all coastlines and coastline development will be affected. In most larger continental or sub-continental countries, the coastal area affected will be a snail proportion of the total national land area and larger proportions of land and national resources will be unaffected. In those countries and parts of countries, which are extensively flat, areas affected by rising sea levels are likely to be a larger proportion of the national whole - with correspondingly less land remaining unaffected. Deltaic plains and their islands are especially vulnerable, such as those on the east and north-east coasts of India and in particular, the Ganges- Brahmaputra-Keghna delta of Bangladesh. The regular experience in the Bay of Bengal of tropical cyclones and their associated sea-surges make low lying areas particularly prone to rising sea levels - the base upon which tropical cyclones are formed and upon which they develop their catastrophic damage potential, unimpeded as they sweep inland. In island countries surrounded by their oceans, the proportion is greater of coastal areas directly affected by rising sea levels. Hot only is it the amount of land affected in small island countries, but the proportion of land in each island affected which is so much greater and which leaves proportionately so much less land and resources unaffected. Though the proportional impact of sea-level rise is generally the greater in island countries, the topography of each island will determine the rate and extent of its effects. Coastlines of some islands may include the island entirety and proportional impact of sea level rise will be greatest of all on low-reef and atoll islands. Rising sea levels bring the need for increased urgency for understanding of hazards and in implementing measures and adjustments on their behalf, lew and expanded initiatives are required to facilitate the sharing and exchange of knowledge and experience between island countries and between island and continental countries of the Commonwealth. This, and other Reports for the Commonwealth Expert Group, should be made the basis of training and education programmes, out of which implementation projects for specific measures can be identified and implemented where these are most needed. Regional and inter-regional initiatives are an appropriate Commonwealth medium for this process. Holistic survival strategies are required as integral components of coastal zone human ecology and its management, to take account of vulnerability reduction, preservation and conservation of natural protective features and traditional knowledge, and the identification, transference and implementation of measures for vulnerability reduction and preparedness, 2 Island Variety Twenty-six Commonwealth Member States are island countries (UHCTAD 1979) and twenty-one of these are small island developing countries (Commonwealth Secretariat: 1985), amongst a total Commonwealth Membership of 48. An additional 21 island countries are included amongst Special Members, self governing states in association with Member Countries, and dependant territories of Member Countries. Table 1 shows the extraordinary range and variety of areas, populations and population densities of Commonwealth countries. The island country of Papua Few Guinea has a land area almost twice that of Great Britain and of half as much again as New Zealand (comprising two principal islands). These two countries are included as Commonwealth Member Island Countries (Table 1). The population density of Great Britain is exceeded by thirteen other Commonwealth island countries (eg Barbados; The Maldives; St Vincent; Sri Lanka; Tuvalu). Some archipelagic island countries, such as The Cook Islands, have a total land area less than some of the smallest single- island countries (eg 5iue). Archipelagic countries may contain several islands, such as Western Samoa, hundreds of islands as in Tonga, or thousands of islands as in The Maldives. Some of these islands may not be permanently inhabited and amongst those which are, population density is widely variable. Some islands are mountainous (Vanuatu) and some are atolls (Tuvalu); other