Vulnerabilities

Civil engineering work management restrictions

The modification of run-offs and external flows is likely to affect the management of major dams. This will require a specific outlook (1).

The French railway system

According to the French railway company SNCF the French railway network is globally robust to potential climate changes (2). Some extreme events might produce disruptions difficult to deal with, such as rail buckling during heat waves, fires because of droughts, flash-floods in the south of France, and landslide because of heavy rain (3). Old infrastructure and equipment are particularly vulnerable to this type of events.
But there are also large security margins: stabilized renewed railways tracks can for instance withstand temperatures up to 60 °C. Recent drainage systems and major engineering works are designed to cope with at least a 1:100-year flood event. In addition, adaptation measures are implemented continuously in a reactive mode. After the 2003 heat wave, SNCF took important measures: release of a reinforced heat wave contingency plan, establishment of an annual heat-day for a check-up of critical equipment, adjustment of temperature class specifications for the new regional rolling-stock, modernization of decision support tools to optimize monitoring and maintenance, etc. (2).

Winter sport facilities on permafrost

Approximately 20 million square kilometres of the planet’s emerged land mass is covered with permafrost. About a quarter of this is located in mountainous terrain (6). In high mountain areas, melting permafrost may damage the infrastructure of winter sports facilities. For the first time, the vulnerability of these infrastructures was assessed for the entire French Alps by carrying out an inventory of damage that has occurred since 1990 (5). The study area encompasses 200 ski resorts, representing a total of about 3000 ropeway transport systems (chairlifts, gondola lifts, surface lifts), buildings, avalanche control and protection systems, and communications networks.

Out of 947 infrastructures built on permafrost in the French Alps, 12 infrastructures have already been subject to repeated instances of disruption and deterioration over the past 30 years. Most of the damages recorded, such as destabilized pylons of ski lifts, were in areas where permafrost degradation was fully expected (ice-rich terrain). Four categories of deterioration were distinguished: tilting of the infrastructure due to creep or subsidence, subsidence of ground level due to melting of ice, structural and foundation cracking, and sudden or progressive collapse with deterioration of the foundations and anchor points (5).

The percentage of damaged infrastructures seems to be small still, but may be increasing in time in response to changes in permafrost conditions (7). The number of damage cases has doubled between 2010 and 2018 compared with the period 2000-2010, while the number of infrastructures built in high mountain areas has increased only slightly since the 1990s (5). 

Adaptation strategies

The French railway system

As a first necessary step to improve readiness and to anticipate what the consequences of climate change might be, the understanding of the existing interactions between the infrastructure components and climatic conditions should be improved. There is currently very little aggregated quantified information about the impact of weather on the French railway system (2).

Climate change disturbs the present-day relationship between infrastructure management and extreme weather conditions. With more extreme episodes and less historical data on their statistical distribution it becomes harder to keep the infrastructure fitted to different contexts (4). This creates new uncertainties that could be better managed with a proper use of climate change scenarios and a sustained dialogue between climate scientists and engineers that has not yet been set up (2).

Winter sport facilities on permafrost

Winter sports infrastructures were often built without prior geotechnical investigations to determine ice content and soil characteristics. Preliminary geotechnical investigations could have solved most of the problems due to melting permafrost that have occurred in the last 30 years if they had been carried out during the initial project and not after the deterioration (5). 

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for France.

1. ONERC (2007/2009)
2. Dépoues (2017)
3. Stamos et al. (2015), in: Dépoues (2017)
4. Edwards (2003), in: Dépoues (2017)
5. Duvillard et al. (2019)
6. Gruber (2012), in: Duvillard et al. (2019)
7. Ravanel and Deline (2010); Ravanel et al. (2013); Bodin et al. (2015); Schoeneich et al. (2015); Ravanel et al. (2017), all in: Duvillard et al. (2019)