Bornholms Regionskommune has addressed the island's unique challenges resulting from climate change with its 2022 climate adaptation plan. As Denmark's only island municipality, Bornholm faces particular climate threats that require tailored solutions adapted to the island's geological conditions and coastal exposure. The plan has been prepared as part of the DK2020 project and aims to ensure that Bornholm becomes climate neutral and resilient by 2050 at the latest. The island's particular geography creates unique climate challenges compared to other Danish municipalities. Northern Bornholm is dominated by bedrock, while the southern part consists of sandstone and shale, resulting in very different runoff conditions. The narrow watercourse catchments mean that streams and brooks react extremely quickly to rainfall events, and the low infiltration in the bedrock sends most of the rainwater directly to the watercourses. At the same time, most larger towns are located on the coast, where they are exposed to both extreme rainfall and storm surge. The five commercial harbours in Nexø, Rønne, Hasle, Allinge and Tejn constitute a particular focus area in the climate adaptation plan. With an expected sea level rise of 27 cm by 2050 and 80 cm by 2100, harbour areas are particularly vulnerable. Allinge and Tejn harbours are assessed to be at greatest risk, as they already experience damage from storms, including damage to the outer breakwater and gate during the storm in October 2020 and New Year 2021. The plan's most comprehensive effort is the mapping of 14 risk areas and designation of 34 physical measures targeting flooding. Of these, 21 measures target extreme rainfall, 8 target storm surge, 4 target groundwater and one targets watercourses. Particularly ambitious are the plans to view rainwater as a resource that can be incorporated into multifunctional solutions such as sports pitches for storage and rainwater basins that can be expanded to handle extreme rainfall. A significant challenge is the plan's limited focus on CO2 reduction. As a pure climate adaptation plan, it lacks concrete targets for emission reductions and sector-specific measures to achieve climate neutrality by 2050. The plan itself acknowledges that drought and heatwaves require further analysis, as the level of knowledge is not considered sufficient to determine concrete measures. Citizens and businesses are assigned a central role in the plan's implementation. The municipality will act as a facilitator for joint projects, particularly in areas such as Balka, Snogebæk and Sømarken-Dueodde, where high groundwater levels create problems for many properties. Private property owners are encouraged to form ditch cooperatives and enter agreements on upstream water retention to protect lower-lying homes. With this approach, Bornholm aims to become a model for how island communities can adapt to the realities of climate change.

Source: Bornholms Klimatilpasningsplan (2022)