Implications of Expected Climatic Changes for the Cres-Lošinj Islands

Field: Environmental Science (Physical Sciences)

The present study based on extrapolations from the best available data and the scenarios described by Palutikof and Wigley in this volume identified four potentially major, specific impacts that may become gradually apparent by the middle of the next century in the Cres and Losinj archipelago. (a) Gradually increasing salinity of the waters of Lake Vrana, which is at present virtually the sole source of freshwater on the archipelago, due to penetration of sea water into the aquifers feeding the lake as a consequence of sea level rise. (b) Flooding of some present coastal urban areas and infrastructure, due to the rise in sea level. A mean sea level rise of 1 m would inundate about 35 ha of the economically and historically most important urban areas, housing about 13% of the archipelagos present population. (c) An extended tourist season owing to elevated average temperature. An increase of about 2°C in the mean temperature (anticipated to occur by the year 2030) could extend the tourist season from the present three to five months. (d) Increased risk of forest fires owing to the increase in temperature, with concurrent decrease in humidity and soil moisture during the summer season. Other potential impacts may include: ˇ increased erosion of sandy beaches and slumping of coastal flysch sediments (e.g. at Susak) ; ˇ accelerated erosion and loss of topsoil ; ˇ increased air pollution from sources outside the archipelago due to changes in wind patterns, even if the amounts emitted remain at the present levels ; ˇ a northward shift in the present line dividing the evergreen eu-Mediterranean forests from the deciduous sub-Mediterranean forests, and disappearance of some species at present inhabiting the southern limit of their natural distribution range (e.g. chestnuts) ; ˇ increased marine primary productivity, with resulting potentially positive (e.g. increased fisheries yield) and negative (e.g. algal blooms) consequences ; ˇ opportunities for raising crops requiring warmer climate, but worsening conditions for some present crops such as olives and for livestock such as sheep ; ˇ increased frequency of flooding of coastal structures and installations (e.g. fish canning factory, shipyards, some coastal roads, water supply networks and sewers), and historic centres (e.g. at Cres, Osor, Mali Losinj, Veli Losinj) ; and ˇ increased frequency of diseases such as skin cancer, eye disease, heat stroke, and diseases such as encephalitis and papatachi fever, transmitted by insect vectors. The expected climatic changes will have no, or very little impact on the energy requirements of the archipelago, on the aquaculture potential of the surrounding waters or on the existing hotel buildings. Although the changes indicated above will occur gradually, and may not become apparent before the middle of the next century, the timely, development of policies and measures to adapt to the expected changes and to prevent their negative impacts should not be delayed. It is suggested that during the periodic revisions of the Communal Physical Plan adopted for the archipelago in 1991, the findings and recommendations of the present study should be evaluated and incorporated, as appropriate, into the plan. The main recommendations of the study, which may have to be taken into account, include: (a) research on the hydrology of Lake Vrana should be increased and, depending on the results and the projected demands for fresh water, an early decision should be taken either: ˇ to improve and increase the trapping and storage of peak flows of kantic rivers over the Kvarner mainland and artificially recharge the karstu underground aquifers during the prolonged, dry summer seasons ; or ˇ to ensure the supply of additional quantities of drinking water from mainland sources or, to produce it locally (e.g. by desalination) ; (b) elevation of coastal defence structures in order to protect valuable historic centres, buildings and structures. Development plans should identify vulnerable areas and restrict future developments that may be vulnerable to climatic changes ; (c) evaluation of the opportunities and demands (space and services) resulting from an extended tourist season ; and (d) review of forest management (e.g. clearing of undergrowth, cutting of firebreaks) practices to reduce the increased risk of forest fires.