Changements climatiques et risques naturels dans les Alpes

Einhorn, Benjamin; Eckert, Nicolas; Chaix, Christophe; Ravanel, Ludovic; Deline, Philip; Gardent, Marie; Boudières, Vincent; Richard, Didier; Vengeon, Jean-Marc; Giraud, G.; Schoeneich, Philippe

doi:10.4000/rga.2829

Cited by 29 publications

(9 citation statements)

References 47 publications

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“…Questo porta a ritenere che siano da valutare in modo adeguato, attraverso scenari, gli effetti potenziali sull'organizzazione delle funzioni territoriali e gli usi del suolo delle "fallow land" che si potranno determinare a causa dei cambiamenti climatici in alta quota (Einhorn, 2015), come pure sulla qualità paesaggistica ed ecologica e la disponibilità di risorse naturali, fino a quelli sull'economia e la vita degli abitanti della montagna, anche consolidata nei secoli. L'analisi di questi fenomeni e dei loro effetti implica differenti prospettive circa i futuri usi del territorio alpino che contemplino un'alleanza tra discipline per formulare soluzioni su misura a supporto dei decisori pubblici, che contemplino destinazioni diversificate, innovative o scelte di "alleggerimento" da usi antropici dei territori a rischio, strettamente correlate alla causa della crisi dei territori stessi, anche programmandone il "riposo" preventivo con "fallow land" pianificate.…”

Section: La Perdita Irreversibile DI Un'identità Recente (Cambiamentiunclassified

Le diverse facce della montagna in declino: un’esperienza lombarda

Pedrazzini¹

2019

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Section: La Perdita Irreversibile DI Un'identità Recente (Cambiamentiunclassified

Le diverse facce della montagna in declino: un’esperienza lombarda

Pedrazzini¹

2019

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“…3.2.2), is sufficient to represent the main topographical control on the rock wall temperature distribution, and to drive longterm changes. Permafrost distribution modelling often suffers from coarse topographical resolution which does not represent the natural variability of environmental parameters (Etzelmüller, 2013). Metric resolution is essential for a realistic simulation of rock wall permafrost at the summit scale (Magnin et al, 2015a).…”

Section: Model Dimensions and Resolutionmentioning

confidence: 99%

“…Between the 1990s and 2010s, cold permafrost disappeared and warm permafrost largely penetrated in the shallow layers of the GM and AdM SE faces respectively. Quantitative interpretations about the permafrost lower boundary and its changes are limited by the discontinuous character of mountain permafrost mainly governed by local conditions (Etzelmüller, 2013), topography and transient controls; these different influences are difficult to distinguish (Noetzli and Gruber, 2009). Nevertheless, results of our 2-D simulations clearly suggest that climate change in between the LIA termination and the 2010s, especially since the 1990s, have led to permafrost disappearance below the S-exposed faces at least up to 3300 m a.s.l.…”

Section: Permafrost Degradation Since the Lia Terminationmentioning

confidence: 99%

Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21<sup>st</sup> century

Magnin¹,

Josnin²,

Ravanel³

et al. 2016

Preprint

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Abstract. High alpine rock wall permafrost is extremely sensitive to climate change. Its degradation can trigger rock falls constituting an increasing threat to socio-economical activities of highly frequented areas. Understanding of permafrost evolution is therefore crucial. This study investigates the long-term evolution of permafrost in three vertical cross-sections of rock wall sites between 3160 and 4300 m a.s.l. in the Mont Blanc massif, since LIA steady-state conditions to 2100. Simulations are forced with air temperature time series, including two contrasted air temperature scenarios for the 21st century representing possible lower and upper boundaries of future climate change according to the most recent models and climate change scenarios. The model outputs for the current period (2010–2015) are evaluated against borehole temperature measurements and an electrical resistivity transect: permafrost conditions are remarkably well represented. Along the past two decades, permafrost has disappeared into the S-exposed faces up to 3300 m a.s.l., and possibly higher. Warm permafrost (i.e. > −2 °C) has extended up to 3300 and 3850 m a.s.l. in N and S-exposed faces, respectively. Along the 21st century, warm permafrost is likely to extent at least up to 4300 m a.s.l. into the S-exposed rock walls, and up to 3850 m a.s.l. at depth of the N-exposed faces. In the most pessimistic case, permafrost will disappear at depth of the S-exposed rock walls up to 4300 m a.s.l., whereas warm permafrost will extend at depth of the N faces up to 3850 m a.s.l., but could disappear at such elevation under the influence of a close S face. The results are site-specific and extrapolation to other sites is limited by the imbrication of the local topographical and transient effects. Shorter time-scale changes are not debatable due to limitations in the modelling approaches and future air temperature scenarios.

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“…Global warming is particularly pronounced in high mountain environments and has accelerated in the past decades (Hock et al, 2019). In the French Alps, air temperature has increased by +1.5°C to +2.1°C since 1950 (Einhorn et al, 2015). This has strong impacts on the Alpine cryosphere, such as rising of the rain-snow limit by about 400 m since the 1980s (Böhm et al, 2010), permafrost degradation (Magnin et al, 2017;PERMOS, 2019) and glacier retreat (Zemp et al, 2015).…”

Section: Introductionmentioning

confidence: 99%