30 March 2010 The Impact of Climate Change on the Torres Strait and Australia s Indian Ocean Territories Gavin Briggs Manager Northern Australia Research Programme Summary The impact of climate change will not be limited to mainland Australia s coastal zone. Erosion and gradual inundation are already occurring on the low-lying Torres Strait island communities of Boigu and Saibai. Any future relocation of affected communities will be socially and economically costly. There are also security implications for Australia s northern border region if the extreme scenario of total inundation of most of the Torres Strait region occurs. The Australian Indian Ocean Territories will also face a multitude of risks from climate change. Analysis There are approximately 8,000 islands of Australia spread across the Indian, Southern and Pacific Oceans. Most of them are uninhabited. Due to the variety of locations, geomorphology, weather patterns and climatic conditions of each island, the risks posed by a changing climate will be different. Australia s low-lying island communities, especially those in the Torres Strait and northeast Indian Ocean regions will be at risk from the effects of climate change. This risk will only increase as the effects of climate change become more pronounced. For the seventeen island communities located over five geographically distinct island clusters in the Torres Strait region the potential impact of climate change will be costly and disruptive. Changes in the local eco-systems, rising sea level, hotter temperatures and the spread of diseases will have a significant impact on these communities, especially those located on lowlying islands. The top western islands of Boigu and Saibai, located close to the Papua New Guinea (PNG) coastline, are particularly susceptible to a changing climate and coastal inundation. The Torres Strait region has a strong culture and identity. Each island community has its own language and customs. They are, however, vulnerable to the impact of a changing climate and its effect will be exacerbated by the regions socio-economic factors and its remoteness. The Australian Government s Climate Change Risks to Australia s Coast (2009), states that in comparison to mainland Australia, settlements on islands are very isolated. Damage and destruction in such remote locations will be very difficult and costly to recover from. There are
several effects from climate change which will impact on Australian citizens living in remote and tropical island communities. They include existing health issues exacerbated by climate change and the likely possibility of new health risks emerging. Other risks include the disruption or eventual loss of the supply of energy, water, sewerage, as well as the maintenance services, transport and infrastructure. Projected rises in sea level and temperature will mean that several Torres Strait island communities will be adversely affected at different points in time. There are several islands being slowly inundated by rising sea levels and eroded by king tides and storm surges. The impact of unseasonal and increased frequency of king tides mean some islands are experiencing a reduction in fresh water supplies and damage to local crops. Relocation is likely in the long-term for many living on the mud-islands of Boigu and Saibai. This course of action will be expensive and socially destabilising. The forecast for Australia s future climate Australia s climate will be impacted by a changing climate which will see a rise in temperature and regional sea levels. The Australian Department of Climate Change and Energy Efficiency is clear about their position on climate change. They state that detection and attribution studies of Australian climate indicate that warming of climate is unequivocal. The Minister for Climate Change and Energy Efficiency Senator Penny Wong told the National Coastal Climate Change Forum of 18-19 February 2010 that 2009 was the second hottest year on record in Australia and the fifth hottest globally, and that 2009 finished the hottest decade in recorded history. This trend, according to the Australian Bureau of Meteorology, state that by 2030 the best estimates indicate Australia will face the following climatic situation: A further 1 C of warming in temperatures; Up to 20 per cent more months of drought; Up to 25 per cent increase in days of very high or extreme fire danger; and Increases in storm surges and severe weather events. In regards to sea level, the Department of Climate Change and Energy Efficiency state: Global sea-levels rose 17 cm over the past century; From 1993 to 2003 global sea level rose by about 3.1 mm a year, compared to 1.8 mm a year when averaged from 1961 to 2003; Observed sea level is currently tracking near the upper limit of the Intergovernmental Panel on Climate Change (IPCC) projections from 1990 when the projections were first available; and Over half of the observed sea-level rise is due to thermal expansion of the oceans. Through climate modelling, analysis and scientific rigour, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) state future projections indicate that over the course of Page 2 of 7
this century, the sea level will continue to increase due to warming from both past (20 th century and earlier) and 21 st century greenhouse gas emissions. The CSIRO also claim the most robust projections of 21 st century sea-level rise are the assessments of the International Panel on Climate Change for 2001 and 2007. While some continue to argue about the causes and the potential severity of a changing climate, Australia s most credible scientific organisation, the CSIRO, project that the global mean sea level will continue to rise. The following graph (figure 1) illustrates a rising sea level over the long-term. Sea Level Rise 1990 2100: Projections for the 21 st Century 1 (Figure 1) Source: http://www.cmar.csiro.au/sealevel/sl_proj_21st.html The IPCC Fourth Assessment Report (2007) has said with very high confidence that coasts are experiencing the adverse consequences of hazards related to climate and sea level. The IPCC also claims, with very high confidence, that a sea-level rise will further exacerbate inundation, erosion and other coastal hazards, threaten vital infrastructure, settlements and facilities, and 1 The CSIRO Marine and Atmospheric Research: The central dark shading is an average of models for the range of SRES greenhouse gas emission scenarios. The light shading is the range for all models and all SRES scenarios and the outer bold lines include an allowance for land-ice uncertainty. The updated AR4 IPCC projections of 2007 for the SRES scenarios (Meehl et al. 2007) are shown by the bars plotted at 2095. The magenta (lighter) bar is the range of model projections (90% confidence limits). Ocean thermal expansion and melting of glaciers and ice caps are the largest contribution to this range. The red bar is a potential but poorly quantified additional contribution from a dynamic response of the Greenland and Antarctic ice sheets to global warming. Note that the IPCC AR4 states that larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea-level rise. http://www.cmar.csiro.au/sealevel/sl_proj_21st.html Page 3 of 7
thus compromise the socio-economic well-being of island communities and states. By 2100, the IPCC s projections are that global sea level rises could be 18-95 cm, with an additional rise occurring from melting polar ice sheets. The following CSIRO graph (figure 2) illustrates that there has been an upwards trend in the global mean sea level for well over the last century. (Figure 2) ource: CSIRO, Sea Level Rise Understanding the past Improving projections for the future http://www.climatechange.gov.au/en/climate-change/trends/sea-level.aspx The Bureau of Meteorology s submission to the Inquiry into Climate Change and Environmental Impacts on Coastal Communities stated that many of the IPCC findings underline the need for further efforts in understanding some of the key uncertainties in how climate change will impact on the coastal environment. The Bureau, in conjunction with the CSIRO through the Centre for Australian Weather and Climate Research, climate modelling and technologies were being developed which are of particular significance because they study the impact of climate change as it affects Australia. The Bureau states that while much of the globe is developing climate modelling, their emphasis is often not on Australia or even the Southern Hemisphere. In a submission to the House or Representatives Standing Committee on Climate Change Water, Environment and the Arts on 26 May 2008, the Bureau of Meteorology stated global climate models also indicate that mean sea-level rise on the east coast of Australia may be greater than the global mean sea-level rise. They also noted that climate change trend needs to be understood in the context of regional variability in sea level. It is important to note that the sea level rise (or fall) is not globally uniform. The following regional analysis of sea level rise shows that it has been particularly marked for the region that Page 4 of 7
includes the Torres Strait region. The CSIRO Marine and Atmospheric Research note that this graph (Figure shows there is a clear pattern of sea-level change that is also reflected in patterns of ocean heat storage. Sea Level Trends Regional Trends: 1993 to 2009 (Figure 3) Source: http://www.cmar.csiro.au/sealevel/sl_hist_last_15.html Increases in sea level and changing weather patterns, such as wind, wave and temperature, will contribute to more frequent storm surges and tides. This will impact on low-lying islands ability to protect their fresh water supplies and crops. The IPCC also claims with very high confidence that under most climate change scenarios, water resources in small islands are likely to be seriously compromised. This means fresh water supplies for many of Australia s low-lying island communities will be increasingly at a greater risk to the effects from a changing climate. In January 2009, a king tide in Saibai produced extensive flooding, reminding many in the Torres Strait region of just how precarious their fresh water supply is to inundation and sea water contamination. A 2009 risk assessment report on climate change and the Australian Indian Ocean Territories by Maunsell AECOM stated that there was a large potential for storm tides to have an impact on Cocos (Keeling) Island s southeast and southwest ocean facing coastlines. While the report noted that the last storm surge was recorded on 27 November 1909, changes in future Indian Ocean wave patterns will cause a potential increase of the swells during autumn and winter periods. Christmas Island is less vulnerable to storm surge and tides because of its geographical features, such as its high cliffs and lack of a surrounding shallow shelf. The part of this island most vulnerable, however, is the northeast settlement and its port facilities. The shore terrace of Kampong has been identified as being at risk to storm surge, and Isabel Beach and Rocky Point are at risk to wave overspill. Page 5 of 7
Australia s low-lying island communities of the Torres Strait: Boigu and Saibai There are five traditional island clusters in the Torres Strait region. They are the Top Western islands which includes Boigu and Saibai, and the Western, Central, Eastern and Inner Islands. Despite the various physical differences of each island cluster, there are some similarities such as their remoteness, small land mass, and a limited capacity to absorb natural disasters and climatic extremes. Major environmental change from climate change will present many challenges to these small island communities, especially due to their geographical constraints, limited resources and a reliance on a restricted economic base. Source: Torres Strait Regional Authority The Torres Strait has 17 island communities and has a total population of 18,000 people. The islands stretch across the Torres Strait in an area between Cape York and the southern PNG coast line. The mud island of Saibai is approximately three kilometres from the PNG coastline. The entire Torres Strait region includes over 100 islands and many face significant coastal hazards, such as erosion and inundation, and are extremely vulnerable to any significant sea level rise. A worst case scenario is that over the long-term, a large sea-level rise could see some islands completely inundated. The uncertainty continues for communities living on Boigu and Saibai. They too face the threat of a loss of lifestyle and livelihoods from king tides and storm surges. In time, this could result in their relocation from their islands. The land is owned by the Islanders yet the buildings and associated infrastructure is owned by the Queensland State Government. The Australian Government has a number of agencies on these islands, including Defence, Australian Federal Police, Customs and Border Protection, and Quarantine and Inspections Services. These two Torres Strait islands face the most imminent danger from the effects of climate change. Salt water inundation from storm surges, king tides and rising sea levels have already threatened the fresh water supplies and damaged crops. Palms and trees exposed to storms can
die from their roots losing their grip in sand which is washed away. The consequence of such unseasonal storms includes the destruction of crops and loss of fresh drinking water. This means there will be a need for assistance from State and Federal governments to assistance Torres Strait islanders mitigate the ongoing implications of climate change. There is a possibility that for some 2,000 Torres Strait islanders from several local communities, especially those living on mud-islands, relocation is likely to be an outcome. Australian Indian Ocean Territories Situated approximately 2000 kilometres west of Darwin are the Australian Indian Ocean Territories of Christmas Island (10 30 S; 105 40 E) and Cocos (Keeling) Islands (12 30 S, 96 50 E). A distance of approximately 970 kilometres separates the two islands. These islands are both non-self governing external territories and face risks associated with climate change, such as storm surge, sea level rise, cyclonic activity and sea surface temperature increases. Both Christmas Island and Cocos (Keeling) Island have significant strategic and geopolitical value for Australia. This is due to their location as a forward position far from the Australian mainland in the north-east quadrant of the Indian Ocean and the exclusive economic zones which radiate out from these islands. There are several Australian Government departments and agencies which use these islands for a variety of purposes which serve the national interest. The impact of climate change differs between these two Australian Indian Ocean Territories. The elevation of Cocos (Keeling) Island is generally one and four metres and all its 27 low-lying coral atolls will be particularly affected by a rise in sea level, as well as an increased frequency and severity of storm surges and cyclonic activity. Inundation would especially affect 80 per cent of its population whom live on the low-lying Home Island. Inundation is not so much an issue for Christmas Island. Its 80 kilometre coastline is an almost continuous sea cliff which reaches heights of up to twenty metres and the highest point on the island is some 360 metres above sea level. The problem that climate change means is that where there are breaks in the coastline that provide access to shallow bays and coral beaches, access to the island s main port at Flying Fish Cove will be further restricted. Presently, ocean swells prevent access to this port for most of the year which exports mining commodities and imports all of the island s non-perishable foods. The impact from climate change will further limit access to the island s port, impacting the local economy and food supplies. The effects of climate change will have regional impacts. Australia s populated low-lying islands will be particularly at risk. The risks associated with the effects of climate changes, such as a rise in sea level, will present a host of issues which will exceed the capacity of local communities in the Torres Strait and Indian Ocean Territories to absorb and adapt to these changes. Published by Future Directions International Pty Ltd Desborough House, Suite 2, 1161 Hay Street, West Perth, WA 6005, Australia Tel: +61 (0)8 9486 1046 Fax: +61 (0)8 9486 4000 Email: gbriggs@futuredirections.org.au Web: www.futuredirections.org.au Page 7 of 7