Using adaptation tipping points to prepare for climate change and sea level rise: a case study in the Netherlands

Studies on the impact of climate change and sea level rise usually take climate scenarios as their starting point. To support long-termwater management planning in the Netherlands, we carried out a study that started at the opposite end of the effect chain. In the study we refer to three aspects of water management, flood defense, drinking water supply, and protection of the Rotterdam Harbour. We examined whether, and for how long, current water management strategies will continue to be effective under different climate change scenarios. We did this by applying the concept of ‘adaptation tipping points’, and reached it if themagnitude of change is such that the current management strategy can no longer meet its objectives. Beyond the tipping points, an alternative adaptive strategy is needed. By applying this approach, the following basic questions of decision makers are answered: what are the first issues that we will face as a result of climate change and when can we expect this. The results show, for instance, that climate change and the rise in sea level aremore likely to cause a threat to the fresh water supply in the west of the Netherlands than flooding. Expressing uncertainty in terms of the period that the existing strategy is effective (when will a critical point be reached) was found to be useful for the policy makers