| Popis: |
Tipping points are an emerging concept in climate change research and communication. However, previous research has strongly focussed on tipping points in biophysical systems, which left the potential for climate change induced socio-economic tipping points (SETPs) mostly unexplored. The objective of this thesis is to identify and assesses SETPs in order to support decision making on climate policy. A SETP is defined as “a climate change induced, abrupt change of a socio-economic system, into a new, fundamentally different state”. SETPs are characterised by: (1) stable states at two sides of a threshold; (2) a non-linear change mechanism, and (3) rapid change while passing the threshold. Examples are: the collapse of winter sports tourism, farmland abandonment, and sea-level rise-induced migration. The clearest examples of SETPs are likely to be found on small scale homogeneous systems, that can exhibit a system-wide uniform response to a climate driver. When modelling SETPs, there is an extra layer of complexity compared to biophysical tipping points, because of the complex dynamic character of the socio-economic system and the fact that humans proactively and autonomously alter the system to anticipate biophysical change. This thesis presents a stepwise approach for identification and assessment of SETPs, which in seven steps guides the researcher through key study design choices. The first application is urban water security. The essence of urban water security lies in an adequate response to partly inevitable system pressures, with well-functioning infrastructure that prevents adverse impacts such as flood damage. At the same time, in cities under pressure, like Amsterdam and Rotterdam, flood pressures may always propagate along the cause-effect chain via an unexpected mechanism. For example, a flood or near-miss experience could lead to the SETP of an abrupt house price collapse. Stepwise SETP-assessment shows that house price collapses could happen under conditions of high-end sea level rise, reactive flood risk management, and slow measure implementation. A new policy insight is that this SETP may be avoided by managing risk perceptions; when all buyers and sellers on the housing market are aware of gradual changes in flood risk, large fluctuations in risk perceptions and related house price booms and busts may be prevented. The second application field is the road transport infrastructure of thirty European countries. The SETP investigated is an abrupt large-scale malfunctioning of the road network from a river flood event. National-scale SETPs are most likely in small mountainous countries like Slovenia, Macedonia and Albania, where the 5% least favourable small-scale flood events may already disrupt some 30-40% of the preferred routes between major economic regions. Targeted flood proofing of a few critical weak spots by road operators could be a relatively easy, yet very effective, way to enhance the network robustness. Many countries have certain regions that could abruptly become poorly accessible during river floods. Such regional-scale tipping points seem to be much more likely and policy relevant than large national-scale disruptions. The third application is winter sports tourism. For six ski resorts in the Swiss Alps, the SETP of an abrupt bankruptcy is investigated. Bankruptcy might follow when in consecutive years, the number of days with good snow conditions falls below a critical threshold. The effectiveness of incremental and more transformative adaptation, resp. artificial snowmaking and year-round business model diversification, is explicitly modelled. The resulting policy insight is that beyond 2050, low-altitude resorts cannot avoid SETPs with artificial snow making alone, and can only survive with economic diversification towards year-round, less snow-dependent activities. Higher-altitude resorts must be aware that ski lift and real estate investments come with a long-term commitment to artificial snow making to avoid SETPs. |
