Climate adaptation for the Wadden Sea coast in the 21st century

The climate is changing: the earth is warming up and the sea level is rising, with an increasing impact on our ecosystems, the way we grow our food, and the way we live. A large number of these challenges, which will only increase in the future, are already affecting the Wadden Sea coast, an intertidal area behind the dike that protects the region against the Wadden Sea and is unique in the world.

The Climate Adaptation Summit (CAS) was held in the Netherlands in 2021. This worldwide summit contributes to the activity of the Global Commission on Adaptation (GCA) to obtain more support all over the world for climate adaptation. With a view to the CAS, the Programme for a Rich Wadden Sea (PRW) invited Strootman Landschapsarchitecten to draw up an adaptation strategy: a strategy for climate adaptation on the Wadden coast that sets priorities, inspires and looks forward towards an attractive, integral, climate-resistant future in the 21st century. The challenges and opportunities facing this region offer inspiration for similar deltas worldwide.

The choices we make now determine the field of play in the future. That is why the strategy looks beyond the horizon of 2050. Action can already be taken on the basis of our adaptive solutions. What is more, they are in harmony with the positive developments that are already in place. It is an overarching perspective with interaction between sea and land and a stacked perspective, since the solutions that we propose not only contribute to climate adaptation but also have positive effects for agriculture, biodiversity and the quality of life.

The greenhouse effect causes the temperature to rise, changing precipitation patterns, a rising sea level, increased salinity, new storm systems and acidification of the ocean. The first three of these phenomena in particular have tangible effects on the Wadden coast area. The rise in temperature produces negative effects on nature and agriculture and the warmer climate becomes noticeable. Changing precipitation patterns lead to more frequent drought and flooding with the concomitant negative effects. The rise in the sea level affects water security, increasing salinity, freshwater drainage and marine life in the Wadden Sea. These effects are becoming not only greater but also more unpredictable.

In working sessions with a sounding board group and experts we have identified three climate adaptation issues for the Wadden coast: 1) ensuring coastal safety, 2) maximal utilisation of freshwater and 3) countering the decline of biodiversity. There are 101 adaptation possibilities. We are recommending solutions that serve several purpose, for example, the strengthening of the landscape identity by making its cultural history visible, or new opportunities for (sustainable) agriculture, recreation and tourism, but also more palliative targets such as the reduction and fixation of CO2 emissions. Our scenarios designed to ensure a safe coastal landscape are aimed at an area behind the dike with sea-resistant landscapes that are safe, ecologically interesting and offer economic opportunities. The maximal utilisation of freshwater requires a water system that can handle both extreme drought and extreme precipitation, and moreover a system that can solve this problem at the regional level. A combination of low water retention, some storage and a high level of discharge offers opportunities for a reversion to high water retention, more storage and discharge only when it is really necessary, ‘Not a drop of unused freshwater to the sea’ is the motto on which the strategies that we have designed for this are based.

Habitats both inside and outside the dike are under pressure from the rise in temperature and sea level and increasing drought. This trend is likely to continue. So strengthening nature on the coast of the Wadden Sea is vital, and this can best be achieved with habitats that are in good shape – such as freshwater-saltwater transitions – and nature areas that are connected. The scenarios that we have designed with this purpose in mind make the nature more robust. Here too the result is a combination of factors, such as the deployment of the water network of creeks and waterways for water catchment and ecological veining.

The debate that can be conducted with the recommendations of the report is about the challenges and choices that are made. What are we doing now, what will the landscape look like in eighty years’ time, and how do we get there? We have named seven hotspots in the report that can help. These are locations where many challenges are combined and where projects are already under way, but where the time horizon of 2100 is not yet being taken into account.