An estimated 180,000 islands stretch out around the world (about 50% of which have a surface area of less than 150 km²), a million if small islands and rocks were included. The importance of these unique environments is recognised worldwide: although they account for only 5% of the earth’s surface, islands host 20% of terrestrial plants and vertebrates, and 600 million people depend on island ecosystem services for water, food, shelter, medicine, and the resources needed for their daily lives (CBD, 2010).

Various threats originary from global changes endanger their natural, cultural, economic and social heritage, such as; pollution (waste and water), biological invasions, worsened by poor connectivity with neighbouring ecosystems, climate change, in some cases is even threatening to submerge certain areas such as the coral islands of the Pacific or the Indian oceans, and particularly due to land development, the destruction of habitats and landscapes.

Even though sustainable resource management problems (drinking water supplies and wastewater treatment, access to renewable energy sources, waste management, protection of local bio- and agro-biodiversity) and enhancing the value of heritage (natural, landscape and cultural) are not specific to islands, these issues are particularly acute there: isolation, the rarity of resources, limited space, lack of locally available technologies, in other words their «insular nature» generally reduces their range of solutions.

Therefore, small islands share a range of issues, which then lead to shared solutions.