Small islands are very much in the front-line of climate change with its impacts on people, economies, tourism income and ecosystems likely to be severe according to the Intergovernmental Panel on Climate Change (IPCC).
Nevertheless there is tremendous scope for accelerating adaptive measures that can reduce that vulnerability and assist small island countries and communities to cope. These could also contribute to other key goals including poverty eradication, energy security, better waste management, healthier fisheries and improved water supplies.
Adaptive measures include the rehabilitation and conservation of natural sea defences and fish nurseries like mangroves and coral reefs. Reforestation projects, aimed at building resilience against storm surges and more intense Tropical cyclones, are other measures.
Adaptation can also involve rainwater harvesting and increased deployment of desalination to turn seawater in freshwater—a technology that is starting to be used in countries like Barbados and Tuvalu—along with creative insurance schemes, tapping traditional knowledge, diversification of livelihoods and improved and traditional building designs are
Increased use of renewables including accelerating the commercialization of ones like ocean thermal energy conversion (OTEC) could also assist in cutting energy import bills and managing the physical and economic impacts of climate change. OTEC systems exploit the energy difference between the surface and deeper parts of the ocean to generate electricity.
Achim Steiner, Executive Director of the UN Environment Programme (UNEP) which is the co-founder of the IPCC, said:” Small islands, along with the Arctic and low lying developing countries, are in the front line in terms of climate change. Small islands are, as a result of their size, limited natural resources including energy and water supplies, physical locations, distance from markets and other factors already vulnerable to extreme weather events and other economic shocks”.
“Working Group II of the fourth IPCC report flags the serious and significant future impacts facing small islands unless greenhouse gas emissions are cut. But the report is not a counsel of despair. It also points to significant opportunities to adapt small island economies to buffer against some of the most serious and likely impacts,” he added.
The report says that air temperatures are likely to rise across all small island regions. By 2100 the largest increase is expected in the Mediterranean of between 1.20 degrees C and over seven degrees C followed by the Caribbean and the Northern Pacific with a roughly one degree C to over four degree C increase.
The Indian Ocean is likely to see a between one and just under four degree C rise followed by the Southern Pacific with a rise of somewhere one degree C to just over as three degree C climb.
Future changes in rainfall patterns, coupled with storm surges leading to salt contamination of freshwaters will be a key challenge for many small islands. For example a 10 per cent reduction in average rainfall by 2050 is likely to reduce the floating freshwater store—known as the freshwater lens-- on the Pacific Island of Tarawa Atoll, Kiribati by a fifth.
A reduction in the size of the island, as a result of land loss from sea level rise, would reduce the thickness or depth of the freshwater lens by close to a third. Meanwhile, rising sea levels may also raise water tables close to or above the surface on some small islands increasing the rate of losses from evaporation.
Many small islands in the Caribbean are also facing increased water stress as a result of climate change, especially during the summer months. It is likely that most will be unable to meet islanders’ needs during low rainfall periods.
Climate change may also affect the El Nino Southern Oscillation (ENSO) and its related La Nina event. During the La Nina of 1998-2000, Indian and Pacific Ocean countries suffered acute water shortages with borehole yields in Fiji and Mauritius decreasing by 40 per cent during the dry periods with knock on effects on the exports of sugar cane.
Improved management of water supplies could help. Some water supplies in the Pacific are routinely polluted by herbicide and pesticide run offs from agriculture and other pollution sources. Current economic losses may amount to over three per cent of an island’s GDP.
Others are turning to desalination although the costs of the technology can be high. Such countries include the Bahamas, Antigua and Barbuda, the Maldives, Seychelles, Singapore and Tuvalu.
Sea Level Rise and Extreme Weather Events
Sea levels are expected to rise by between close to 0.20 cm and nearly 60 cm by the end of the century but the rises may not be uniform due to other regional, oceanographic and geological factors.
Meanwhile the number of intense tropical cyclones could increase by 2050 although the total number of cyclones may decline. Wind speeds could increase by up to 10 per cent and the level of rainfall linked with cyclones could climb by 25 per cent with impacts such as bigger storm surges.
Scientists are also trying to get to grips with the phenomena of ‘deep ocean swell’ which may have important implications for small islanders’ coastlines. In places like the Caribbean and the Pacific, more than 50 per cent of the population live within 1.5km of the shore.
It may also has implications for infrastructure in smaller islands in the Caribbean and Indian and Pacific Oceans. Many of their capital cities, airports and roads are on or close to the shoreline.
Agriculture and Biodiversity
An island with relatively high land, such as Viti Leru, Fiji, may suffer annual agricultural losses of between just over $20 million to $50 million by 2050—equivalent to up to three per cent of Fiji’s GDP.
Low lying islands such as Kiribati’s Tarwa group may be facing average annual losses of between $8 and $16 million a year—equal to around 17 per cent of Kiribati’s current GDP.
These will be as a result of droughts, loss of soil fertility and degradation due to more extreme rainfall. The kinds of likely economic impacts can be witnessed in places like Niue. The Paciic island was turned from a food-exporting country to one dependent on imports for two years following Tropical Cyclone Ofa in 1990.
Hurricane Ivan in 2004 caused agricultural losses in Grenada in the Caribbean equal to 10 per cent of GDP. Damage to the nutmeg and cocoa crop means they will not contribute to GDP or foreign exchange earnings until the mid to late 2010’s.
Many islands have unique biodiversity. By 2050, diseases that affect coral reefs and oysters could become annual events as result of rising surface sea temperatures.
Over a third of turtle breeding sites in the Caribbean may be lost if sea levels rise by 0.5 metres. Islands with moist cloud forests, like Hawaii, can expect to suffer a loss of endemic bird species.
Forest losses could be high as a result of more intense cyclones and hurricanes with evidence that island forests recover more slowly from such events.
Pacific Islands are likely to be a greater risk of invasion by the invasive sim weed. American Samoa could see a 50 per cent loss of mangroves with an anticipated 12 per cent reduction in 15 other Pacific islands.
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