Case Study 1:
Turning points for salmon restoration programmes, Rhine river basin

Social-political thresholds of interest
This case study investigates whether climate change could render the policy to reintroduce the salmon in the River Rhine untenable. Thus the case offers an adaptation turning point assessment for nature policies. Atlantic salmon was a common anadromous fish species in the Rhine that went extinct in the 1950s. Reintroduction started when the Rhine state governments accepted the Rhine Action Plan in 1987. Not only the Rhine national governments, but also regional authorities and NGOs are involved in the implementation effort. Bringing back the salmon is therefore not only an abstract water policy objective, but also an inspiration for many small scale public and private initiatives along the Rhine streams and rivers.

In 2001 the Rhine ministers adopted the ‘Rhine 2020 – Programme on the sustainable development of the Rhine’ (ICPR, 2001), which resulted in an action plan ‘Rhine Salmon 2020’ (ICPR, 2004). The main objective is the re-establishment of a self-sustaining, wild Atlantic salmon population in the Rhine by 2020. As such it contributes to policy efforts to enable fish migration in the Rhine river basin and improve habitat conditions. In total, investments of €528 million for the adaptation of infrastructure (weirs, dams) and habitat restoration are planned until 2015.

Climatic conditions for reaching thresholds
These programs do not consider climate change. However, some of the factors that salmon depends on are projected to be affected by climate change (Bölscher et al., 2013). The most direct link between climate change and the success of the reintroduction programme is through water temperature, which affects the propagation and spawning migration of the salmon. In theory water discharge also influences migration, yet in larger rivers, like the Rhine, it is not physically limiting (Todd et al., 2010).

Literature reports diverse thermal boundary conditions for Atlantic salmon (for an overview see Table 2 in Bölscher et al. (2013)). Two boundary conditions have been identified from literature and expert interviews as particularly relevant for threatening the reintroduction of the salmon: 1) Short but regularly occurring periods with potentially lethal temperatures between 25°C and 33°C, 2) Long periods with mean water temperatures higher than 23°C. In the latter case the time window for salmon to migrate from the sea into the Rhine may become too small.

Following the inventory of critical climate conditions, it is concluded that a water temperature of 23°C is a meaningful threshold value for the success of the reintroduction program. However, it is largely unknown how migration depends on the duration and timing of the period of time that water temperatures are above this threshold. Thus, the finiteness of policy success can only be approximated. Summarizing, the likeliness of an adaptation turning point increases with the number of days that the water temperature is above 23°C.

Adaptation turning points and lessons
To identify turning points associated with the number of days that the water temperature exceeds 23°C, model results were used of van Vliet et al. (2013). Figure 3 shows a distinct increase in this number of days at Lobith, where the Rhine enters the Netherlands from Germany. The figure illustrates the adaptation turning point, assuming that the reintroduction of salmon becomes problematic at a doubling of the number of days with temperature above 23°C from the current 20 days to 40 days.



This implies the need to rethink salmon policies and consider adaptive action. At the European and national scale, already temperature standards for cooling water discharge have been defined that ought to safeguard the ecological status of the river. It is questionable to what extend these standard can warrant policy success as in practice the standards prove to be the result of negotiations in which social-economic considerations have the lead and increasingly administrators can make reasoned deviations in implementation, for example during extreme weather events.

An adaptation option relevant for smaller river branches is replanting of trees and creation of shade. Another notable adaptation option mentioned by stakeholders is to change objectives. For instance, to give up reintroduction of the salmon and decide to take another species as an indicator for ecological improvements. Here the sturgeon could be an example.

Summarising, exposure increases to long periods with mean water temperatures higher than 23°C. Thus, the time window for salmon to migrate upstream may become too small to re-establish a sustainable population. The timing of a turning point for salmon policy remains uncertain due to a.o. climate variability, local water temperature differences and the adaptive capacity of Atlantic salmon. These uncertainties can direct future research.

Case Study 2: Turning points for wine production in Tuscany, Italy

Social-political thresholds of interest
This case study explores wine production in Tuscany, Italy under climate change. Wine production in the region is progressively changing from mixed farming system to specialized viticulture. Part of this change is the rediscovery and improvement of traditional and autochthonous vines and a switch to quality production with lower yields, less chemicals and increased value of produced wine. The number of vine-growing farms has been reduced by half over the last 20 years, while average farm size has increased. Significantly, more than half of the total regional vineyard surface is labelled as Designation of Origin (DO).

The associations and unions in the region offer incentives in support of the above mentioned specialisation. Regione Toscana encourages the renewal of old vineyards, on the basis of farmers application and selection. Associations also create awareness that agriculture has created a unique landscape in Tuscany that is both productive and internationally recognised for its beauty. The image of the vineyard, surrounded by the classic, quiet and clean Tuscan landscape, offers a competitive advantage for the wine that is produced there. Thus, agriculture has both an economic, and environmental and landscape value in Tuscany. At the same time the strict landscape conservation and production rules can limit adaptation.

Farmers in Tuscany already observe consequences of climate change and express an increasing interest in adaptation. A key question is whether climate change will make farmers change grape varieties, move to other locations or switch to other livelihoods. Here it is feared that changes in viniculture could have detrimental effects on the landscape, and therefore on tourism and quality of living. After stakeholder consultation the main questions and thresholds of interest are:

• (when) does wine production in its current form become unviable in the region?
• (when) does adaptation become attractive?

Farmers expressed an immediate interest in two adaption strategies: moving production to higher elevations and changing to new varieties. These adaptive actions have a response time of at least 4-10 years (the time it takes for a new wine yard to become productive). Farmers and government representatives stress the crucial importance of assessing wine quality, rather than the more typically modelled production quantity, as the survival of Tuscan viticulture is strictly linked to its high-quality wines.

Climatic conditions for reaching thresholds
Farmers already observe a strong relationship between an increase in temperature and the reduction of the vegetative cycle of the vine. The grapes are ripening earlier compared to twenty years ago, with consequent advance of harvest operations. Literature finds improvement of wine quality with rising temperature at first, yet falling beyond a certain threshold, depending on variety. This corresponds with a shift in the area best suitable for grapevine cultivation either to higher elevations or to higher latitudes.

Adaptation turning points and lessons
A farmer reaches an adaptation turning point the moment that wine quality drops below a desired quality or wine of a higher quality can be produced at a higher elevation. To assess whether and when this may happen the study used a modelling framework for investigating climate change impacts on viticulture in the Tuscany region (Moriondo et al., 2011). Downscaled climate data (temperature, precipitation and CO2 level from observations and the IPCC SRES scenarios A2 and B2 from different climate models) are input to a vintage quality model for climate change impact assessment. The vintage quality model uses a multi-regressive approach and vintage ratings obtained from the most recently published Sotheby’s vintage ratings. The ratings are on a scale from 0 to 100, with the general categories of 0–39 disastrous, 40–59 very bad, 60–69 disappointing, 70–79 average to good, 80–89 good to very good, 90–100 excellent to superb.


Figure 4: Adaptation turning point for Chianti production in Tuscany. The figure shows quality scores in different elevation classes (average of four climate models (DMI-HIRHAM, ETHZ-CLM, MPI-MREMO, SMHIRCA) for SRES scenario A2)).

Figure 4 shows that in the coming century the quality at higher altitudes is likely to surpass that of the lower altitudes. Best-quality grapevine production areas are projected to gradually move upwards. For the coming two decades the entire area between 200 and 500 m above sea level is projected to be viable for best-quality wine production above 85. Beyond 2045, grapevines in the lower altitude classes progressively move out of the desired quality range of 85, whilst grapevines above 500 m show an excellent quality score.

Figure 4 can also be used to identify turning points for viniculture to move to a higher altitude. For the altitude class of 300 m the figure shows that around 2040 it becomes attractive to move 100 m upwards. Higher altitudes become attractive progressively. Beyond 2060 quality at 300 m may drop below the desired quality score of 85, accentuating the need for adaptation .

The Tuscan analysis shows that turning points in wine cultivation may well occur in the second half of this century, depending on the location of the vineyards. Around the same time that present production may start to become unviable, the production at higher elevation becomes more attractive, opening up an avenue of adaptive action. Such an adaptive pathway will not be taken lightly and the decision will have to be studied in the light of many factors, including the existence of other options to adapt. Changing management practices can reduce the risk and postpone the time by which an adaptation turning point is reached. Yet, there is no guarantee that turning points can be avoided ultimately.

Concluding, the turning points studied for Tuscany were stakeholders motivated. The assessment and the illustrations produces were useful as a discussion tool, both for scientist trying to communicate their insights, and for decision-makers to explore an adaptation strategy.