Contenu du sommaire : Impact du changement climatique sur les dynamiques des milieux montagnards

Revue	Revue de Géographie Alpine
Numéro	vol. 103, no 2, 2015
Titre du numéro	Impact du changement climatique sur les dynamiques des milieux montagnards
Texte intégral en ligne	Accessible sur l'internet

Impact du changement climatique sur les dynamiques des milieux montagnards - Monique Fort
Impact of climate change on mountain environment dynamics - Monique Fort
Changements climatiques et risques naturels dans les Alpes - Benjamin Einhorn, Nicolas Eckert, Christophe Chaix, Ludovic Ravanel, Philip Deline, Marie Gardent, Vincent Boudières, Didier Richard, Jean-Marc Vengeon, Gérald Giraud, Philippe Schoeneich
Sous l'effet des changements climatiques, les territoires de montagne alpins enregistrent des évolutions rapides et manifestes qui suscitent l'attention croissante des populations, des scientifiques et des gestionnaires. Pour mieux faire face aux aléas et aux vulnérabilités spécifiques à ces territoires, l'adaptation de la prévention des risques naturels aux changements climatiques est aujourd'hui prescrite par les politiques publiques nationales et communautaires en vigueur dans l'arc alpin. Cet article passe en revue les progrès récents dans la connaissance des changements perçus, mesurés et projetés à l'échelle des Alpes françaises dans 1) les paramètres climatiques, 2) la cryosphère, les hydrosystèmes et la morphodynamique des versants, 3) les aléas naturels et 4) les risques induits. Cette synthèse renouvelée fournit un aperçu des résultats des projets de recherche, de coopération et de capitalisation sur ces thématiques, acquis pour la plupart au cours de la période de programmation 2007-2013, en s'appuyant sur des bases de données et plates-formes de connaissances développées par différents opérateurs scientifiques et techniques dans le cadre de l'arc alpin. Elle est illustrée par une méta-analyse d'exemples déjà publiés de chroniques d'activité d'aléas hydro-gravitaires, accompagnées des paramètres climatiques identifiés comme « prédicteurs ».
Under the effects of climate change, Alpine mountainous regions are undergoing fast and well-perceptible evolutions, which are attracting the growing attention of people, scientists and managers. To cope better with the hazards and vulnerabilities specific to these territories, the current national and European public policies in the Alpine countries now prescribe adapting natural hazard prevention to climate change. This paper provides a review of recent advances in knowledge on the perceived, measured and projected changes in i) climate patterns, ii) the cryosphere, hydrosystems and geomorphological dynamics on Alpine slopes, and iii) natural hazard evolution and induced risks at the scale of the French Alps. We give a brief overview of new results achieved by research, cooperation and capitalisation projects in these thematic fields during the programme period 2007-2013, which are available on databases, thematic knowledge platforms and observatories developed by different scientific and technical operators in the larger framework of the European Alpine arc. We illustrate this renewed synthesis by published examples of hydro-gravitational hazard activity chronicles, along with climate patterns identified as “predictors”.
Climate change and natural hazards in the Alps - Benjamin Einhorn, Nicolas Eckert, Christophe Chaix, Ludovic Ravanel, Philip Deline, Marie Gardent, Vincent Boudières, Didier Richard, Jean-Marc Vengeon, Gérald Giraud, Philippe Schoeneich
Under the effects of climate change, Alpine mountainous regions are undergoing fast and well-perceptible evolutions, which are attracting the growing attention of people, scientists and managers. To cope better with the hazards and vulnerabilities specific to these territories, the current national and European public policies in the Alpine countries now prescribe adapting natural hazard prevention to climate change. This paper provides a review of recent advances in knowledge on the perceived, measured and projected changes in i) climate patterns, ii) the cryosphere, hydrosystems and geomorphological dynamics on Alpine slopes, and iii) natural hazard evolution and induced risks at the scale of the French Alps. We give a brief overview of new results achieved by research, cooperation and capitalisation projects in these thematic fields during the programme period 2007-2013, which are available on databases, thematic knowledge platforms and observatories developed by different scientific and technical operators in the larger framework of the European Alpine arc. We illustrate this renewed synthesis by published examples of hydro-gravitational hazard activity chronicles, along with climate patterns identified as “predictors”.
Le permafrost de montagne et les processus géomorphologiques associés : évolutions récentes dans les Alpes françaises - Xavier Bodin, Philippe Schoeneich, Philip Deline, Ludovic Ravanel, Florence Magnin, Jean-Michel Krysiecki, Thomas Echelard
La montagne alpine est affectée par des processus géomorphologiques dont l'évolution est en partie conditionnée par la dégradation du permafrost : écroulements d'ampleur variable, déstabilisation de glaciers rocheux ou apparition de dépressions cryokarstiques. Ces phénomènes, par leur intensité, sont susceptibles d'engendrer des risques pour les territoires. Nous proposons une synthèse des connaissances sur l'état actuel du permafrost de montagne dans les Alpes françaises et sur son évolution récente. Cet état de l'art se base sur des travaux de recherche menés depuis une dizaine d'années et les mesures recueillies dans le cadre de PermaFRANCE, le réseau français d'observation à long terme du permafrost de montagne. L'analyse des données à disposition montre ainsi qu'en paroi rocheuse, à 3800 m d'altitude, la température à 10 m de profondeur est comprise entre -4,5 et -1,5°C selon l'orientation, alors que dans les formations superficielles, à 2800 m d'altitude en orientation nord, elle est proche du point de fusion. Depuis le début de ces mesures en profondeur en 2010, une tendance à l'augmentation de la température est observable, corroborée par d'autres forages alpins. Le régime est influencé par l'enneigement, de façon très nette en formations superficielles et beaucoup plus discrète en paroi, ce que les mesures en surface réalisées depuis 2003 montrent nettement. Cette variabilité interannuelle se combine aux tendances de plus long terme qui sont probablement à l'origine de l'évolution constatée des dynamiques géomorphologiques associées au permafrost alpin : augmentation de la fréquence des processus gravitaires du type chute de bloc et fluctuation des vitesses des glaciers rocheux. La recrudescence probable de phénomènes extrêmes comme les écroulements majeurs ou la déstabilisation de glaciers rocheux dans les prochaines décennies pourrait engendrer des risques nouveaux ou accrus auxquels les territoires devront s'adapter.
Alpine mountains are affected by significant geomorphological processes whose evolution is partly conditioned by permafrost warming: rockfalls of various volumes, destabilisation of rock glaciers, and cryokarst. These phenomena, because of their intensity, may generate risks for territories. This paper provides a synthesis of the knowledge about the current status of the mountain permafrost in the French Alps and its recent evolution. This state-of-the-art overview is based on research conducted over the past 10 years and the measurements collected within PermaFRANCE, the French network for long-term observation of the mountain permafrost. The analysis of the available data shows that for a rock wall located at 3800 m asl., the temperature is between -4.5 and -1.5°C at a depth of 10 m, according to the aspect, whereas it is close to the melting point in surficial deposits at 2800 m asl. on a northern slope. Since the beginning of these measurements at depth in 2010, a trend of increasing temperature has been discernible, as found in other alpine boreholes. As clearly shown by the surface measurements conducted since 2003, the thermal regime is influenced by snow, particularly in surficial deposits and to a much lesser extent in rock walls. This inter-annual variability is combined with longer-term trends, which probably induce the observed changes in geomorphological dynamics associated with alpine permafrost: an increased frequency of gravitational processes such as rockfalls and fluctuation in rock glacier velocities. The possible increase in extreme events, such as rock avalanches or the destabilisation of rock glaciers, in the coming decades could create new or increased risks, to which territories must thus adapt.
Mountain permafrost and associated geomorphological processes: recent changes in the French Alps - Xavier Bodin, Philippe Schoeneich, Philip Deline, Ludovic Ravanel, Florence Magnin, Jean-Michel Krysiecki, Thomas Echelard
Alpine mountains are affected by significant geomorphological processes whose evolution is partly conditioned by permafrost warming: rockfalls of various volumes, destabilisation of rock glaciers, and cryokarst. These phenomena, because of their intensity, may generate risks for territories. This paper provides a synthesis of the knowledge about the current status of the mountain permafrost in the French Alps and its recent evolution. This state-of-the-art overview is based on research conducted over the past 10 years and the measurements collected within PermaFRANCE, the French network for long-term observation of the mountain permafrost. The analysis of the available data shows that for a rock wall located at 3800 m asl., the temperature is between -4.5 and -1.5°C at a depth of 10 m, according to the aspect, whereas it is close to the melting point in surficial deposits at 2800 m asl. on a northern slope. Since the beginning of these measurements at depth in 2010, a trend of increasing temperature has been discernible, as found in other alpine boreholes. As clearly shown by the surface measurements conducted since 2003, the thermal regime is influenced by snow, particularly in surficial deposits and to a much lesser extent in rock walls. This inter-annual variability is combined with longer-term trends, which probably induce the observed changes in geomorphological dynamics associated with alpine permafrost: an increased frequency of gravitational processes such as rockfalls and fluctuation in rock glacier velocities. The possible increase in extreme events, such as rock avalanches or the destabilisation of rock glaciers, in the coming decades could create new or increased risks, to which territories must thus adapt.
Evaluation du risque de déstabilisation des infrastructures de haute montagne engendré par le réchauffement climatique dans les Alpes françaises - Pierre-Allain Duvillard, Ludovic Ravanel, Philip Deline
Dans le contexte du changement climatique actuel, les milieux de haute montagne sont soumis à de profonds bouleversements tels que la fonte des glaciers ou la dégradation du permafrost, à l'origine de mouvements de versant au sein des parois rocheuses comme des formations superficielles. Ces processus impliquent des risques directs de déstabilisation pour les infrastructures (refuges, remontées mécaniques, etc.). Dans un but de prévention de ces risques, un recensement des infrastructures de haute montagne dans les Alpes françaises a été réalisé à l'aide d'un Système d'Information Géographique constitué de plusieurs couches de données dont des cartes de la répartition potentielle du permafrost et de l'extension des glaciers depuis la fin du Petit Âge Glaciaire. 1769 infrastructures ont été identifiées dans des secteurs à permafrost probable et/ou éventuellement affectés par le retrait glaciaire. Un indice de risque a été construit afin d'identifier et classer les infrastructures potentiellement à risque. Il inclut une caractérisation de l'aléa et un diagnostic de la vulnérabilité. 10 % des infrastructures sont caractérisées par un risque fort de déstabilisation.
Due to ongoing global warming, high alpine environments are affected by significant changes, such as glacial retreat and permafrost warming, which can trigger mass movements in rock slopes or superficial deposits. These processes generate a risk of direct destabilisation for high mountain infrastructures (huts, cable cars, etc.). To help prevent such risks, an inventory of all the high mountain infrastructures in the French Alps was carried out using a Geographic Information System. This combined several data layers, including the Alpine Permafrost Index Map and glacier inventories since the end of the Little Ice Age. 1,769 infrastructures were identified in areas probably characterised by permafrost and/or possibly affected by glacier shrinkage. An index of destabilisation risk was constructed to identify and rank infrastructures at risk. This theoretical risk index includes a characterisation of hazards and a diagnosis of vulnerability. 10 % of the infrastructures were characterised by a high risk of destabilisation.
Risk assessment of infrastructure destabilisation due to global warming in the high French Alps - Pierre-Allain Duvillard, Ludovic Ravanel, Philip Deline
Due to ongoing global warming, high alpine environments are affected by significant changes, such as glacial retreat and permafrost warming, which can trigger mass movements in rock slopes or superficial deposits. These processes generate a risk of direct destabilisation for high mountain infrastructures (huts, cable cars, etc.). To help prevent such risks, an inventory of all the high mountain infrastructures in the French Alps was carried out using a Geographic Information System. This combined several data layers, including the Alpine Permafrost Index Map and glacier inventories since the end of the Little Ice Age. 1,769 infrastructures were identified in areas probably characterised by permafrost and/or possibly affected by glacier shrinkage. An index of destabilisation risk was constructed to identify and rank infrastructures at risk. This theoretical risk index includes a characterisation of hazards and a diagnosis of vulnerability. 10 % of the infrastructures were characterised by a high risk of destabilisation.
Stratégies d'adaptation des producteurs du Safran de Taliouine (Maroc) face au changement climatique - Larbi Aziz, Widad Sadok
Au Maroc les zones de montagne s'étendent sur près de 26 % du territoire national et abritent 30 % de la population. Elles renferment de nombreuses potentialités agricoles, forestières, pastorales et minières. Les systèmes de production dans ces zones sont caractérisés par une diversification des cultures. Toutefois, ces zones sont devenues vulnérables aux effets du changement climatique. Pour appréhender ces effets auprès des populations montagnardes, nous avons effectué une étude au niveau de l'Anti-Atlas dans la zone de Taliouine. Nous avons analysé la vulnérabilité des productions végétales au changement climatique et avons relevé les formes d'adaptation adoptées par les agriculteurs. Nous avons travaillé sur le safran, culture exigeante en eau mais la plus rentable dans la zone.Nos résultats montrent que la majorité des enquêtés ont senti des variations au niveau du climat de la région : irrégularité des précipitations se traduisant par une diminution en quantité et une mauvaise répartition sur l'année, élévation de la température, réduction de la période de froid et diminution de la quantité des neiges. Ces variations se sont répercutées sur la culture du safran et sur sa productivité. Pour faire face à ces effets, les agriculteurs ont adopté différentes stratégies : la gestion et l'utilisation de l'eau, la diversification des activités agricoles, l'augmentation de la part de l'activité non agricole dans la formation du revenu et la migration saisonnière.
In Morocco, the mountainous regions extend over about 26% of the national territory where 30% of the total population live. They contain opportunities for agriculture, forestry, pastureland and mining. The production systems in these zones are characterised by crop diversification. However, these areas have become vulnerable to the effects of climate change. To understand these effects in relation to the population living in these areas, a study was carried out in the zone of Taliouine, in the Anti-Atlas. The vulnerability of crop productions to climate change was analysed and the different ways of adaptation adopted by farmers were identified. The work was done on saffron, the most profitable crop in the target area even though it requires much water.Our results show that the majority of the farmers surveyed had noticed variations in the climate of the region: irregularity of precipitation leading to a decrease in quantity and an uneven distribution throughout the year; rise in temperature; reduction in the cold period and less snow. These variations had impacts on the cropping system of saffron and its productivity. To cope with these effects, the farmers adopted various strategies: better management and use of water; diversification of agricultural activities; increase in the contribution of non-agricultural activities to their gross income; and seasonal migration.
Strategies used by the saffron producers of Taliouine (Morocco) to adapt to climate change - Larbi Aziz, Widad Sadok
In Morocco, the mountainous regions extend over about 26% of the national territory where 30% of the total population live. They contain opportunities for agriculture, forestry, pastureland and mining. The production systems in these zones are characterised by crop diversification. However, these areas have become vulnerable to the effects of climate change. To understand these effects in relation to the population living in these areas, a study was carried out in the zone of Taliouine, in the Anti-Atlas. The vulnerability of crop productions to climate change was analysed and the different ways of adaptation adopted by farmers were identified. The work was done on saffron, the most profitable crop in the target area even though it requires much water.Our results show that the majority of the farmers surveyed had noticed variations in the climate of the region: irregularity of precipitation leading to a decrease in quantity and an uneven distribution throughout the year; rise in temperature; reduction in the cold period and less snow. These variations had impacts on the cropping system of saffron and its productivity. To cope with these effects, the farmers adopted various strategies: better management and use of water; diversification of agricultural activities; increase in the contribution of non-agricultural activities to their gross income; and seasonal migration.
La télédétection de la neige dans les Andes comme outil de prévision des débits des rivières du Cuyo - Nicolas Delbart, Samuel Dunesme, Emilie Lavie, Malika Madelin, Régis Goma
Dans les Andes sèches d'Argentine, alors que la fusion des glaciers est un enjeu à long terme pour les cultures irriguées du piémont, à l'échelle annuelle la fonte du couvert neigeux est la principale ressource pour les cours d'eau et les aquifères. Dans cette étude, nous tentons d'analyser le lien qui existe entre, d'une part, les variations saisonnières et interannuelles sur la période 2001-2014 des écoulements mesurés en amont des premiers barrages régulateurs de quatre rivières (Mendoza, Tunuyán, Diamante, Atuel) de la région argentine du Cuyo (plus précisément ici la Province de Mendoza) et, d'autre part, celles de l'extension de la couverture neigeuse identifiée à partir de la télédétection (produit MODIS MOD10A2, fréquence hebdomadaire), à l'échelle de chaque bassin versant.Etant donné le régime nivo-glaciaire de ces quatre rivières, les variations saisonnières des débits apparaissent logiquement comme directement liées à celles de la surface du manteau neigeux.Nous observons que les débits en période de hautes eaux (septembre à avril), sont directement liés à la surface enneigée au début de la période de fonte des neiges, soit de septembre à octobre, avec une corrélation de 0,8. De plus, la tendance à la baisse de l'extension de la couverture neigeuse entre 2001 et 2014 explique clairement les diminutions observées du module annuel moyen sur la même période.L'agriculture et les autres activités anthropiques de ces oasis dépendent majoritairement des écoulements superficiels des rivières, qui, comme le démontrent nos résultats, dépendent majoritairement de l'extension du couvert neigeux. Nos travaux montrent qu'il est possible d'utiliser la télédétection pour estimer les volumes moyens sur la période septembre-avril (hautes eaux annuelles) à partir d'images MOD10A2, avec une erreur moyenne de 15 %. Les données MOD10A2 étant disponibles gratuitement 10 jours après leur acquisition, il est possible d'anticiper début octobre, le risque de pénurie pour l'été à venir.
In the Argentinian Dry Andes, although the melting of glaciers is seen as a threat for the long-term water availability needed by the piedmont crops, the annual snowmelt is the main source of superficial water and aquifer recharge. In this study, we analyse the link between the seasonal and interannual variations in the discharge measured upstream of the first dams on four rivers (Mendoza, Tunuyán, Diamante, Atuel) of the Argentinian Cuyo region (in the Federal Province of Mendoza) and those of the snow bed extent as mapped by optical remote sensing (MODIS MOD10A2 product) on a weekly basis in the 2001-2014 period, at the scale of each watershed.For the four snow-glacier regime rivers, seasonal variations in the discharge appear directly related to those of the snow bed surface area in each watershed, as shown previously (Masiokas et al., 2006). We observed that the high-water period (September-April) discharge is directly related to the snow extent at the beginning of the snowmelt period, i.e. in September and October, as revealed by a correlation of about 0.8. Moreover, the decreasing trend in the winter snow bed extent from 2001 to 2014 clearly explains the observed decreasing trend in the annual water discharge.Agriculture and human activities in these oases mostly depend on river discharge, which from our results clearly depends on the snow extent. Our research indicates that it is possible to use remote sensing to forecast the average discharge in the September-April period (high-water season) from MOD10A2 images with an average uncertainty of 15%. As MOD10A2 data are freely available ten days after acquisition, it is possible to anticipate in early October the risk of water shortages in the coming summer.
Remote sensing of Andean mountain snow cover to forecast water discharge of Cuyo rivers - Nicolas Delbart, Samuel Dunesme, Emilie Lavie, Malika Madelin, Régis Goma
In the Argentinian Dry Andes, although the melting of glaciers is seen as a threat for the long-term water availability needed by the piedmont crops, the annual snowmelt is the main source of superficial water and aquifer recharge. In this study, we analyse the link between the seasonal and interannual variations in the discharge measured upstream of the first dams on four rivers (Mendoza, Tunuyán, Diamante, Atuel) of the Argentinian Cuyo region (in the Federal Province of Mendoza) and those of the snow bed extent as mapped by optical remote sensing (MODIS MOD10A2 product) on a weekly basis in the 2001-2014 period, at the scale of each watershed.For the four snow-glacier regime rivers, seasonal variations in the discharge appear directly related to those of the snow bed surface area in each watershed, as shown previously (Masiokas et al., 2006). We observed that the high-water period (September-April) discharge is directly related to the snow extent at the beginning of the snowmelt period, i.e. in September and October, as revealed by a correlation of about 0.8. Moreover, the decreasing trend in the winter snow bed extent from 2001 to 2014 clearly explains the observed decreasing trend in the annual water discharge.Agriculture and human activities in these oases mostly depend on river discharge, which from our results clearly depends on the snow extent. Our research indicates that it is possible to use remote sensing to forecast the average discharge in the September-April period (high-water season) from MOD10A2 images with an average uncertainty of 15%. As MOD10A2 data are freely available ten days after acquisition, it is possible to anticipate in early October the risk of water shortages in the coming summer.
Changement climatique et ressource en eau en Himalaya - Joëlle Smadja, Olivia Aubriot, Ornella Puschiasis, Thierry Duplan, Juliette Grimaldi, Mickaël Hugonnet, Pauline Buchheit
En Himalaya, où la hausse des températures est plus élevée que la moyenne mondiale, les répercussions du changement climatique sur la ressource en eau devraient être particulièrement importantes. Tandis que les spécialistes du climat utilisant mesures et simulations nuancent ce constat en soulignant incertitudes et différences notoires entre l'ouest et l'est de la chaîne, médias et organismes de développement tendent à donner l'image uniforme d'un déficit en eau actuel et à venir. Dans le cadre d'un programme interdisciplinaire (glaciologie, hydrologie, agronomie, géographie) sur le bassin de la Koshi au Népal, nous discutons ces propos en montrant la nécessité de distinguer les situations en fonction des unités géographiques et d'intégrer dans les approches sur ce sujet le contexte culturel, social et économique. Nos enquêtes, réalisées sur quatre terrains représentatifs des milieux népalais, ont eu pour objectif de savoir si les populations constataient des variations de la ressource en eau affectant leurs pratiques (agriculture, élevage, tourisme) et si elles les attribuaient à des changements du climat. Nos résultats montrent des situations contrastées et des changements de pratiques sans relation évidente avec le climat. Ils apportent, entre autres, des informations sur la neige, paramètre mal mesuré et sous-estimé dans les simulations et montrent que les populations sont plus affectées par les fluctuations des régimes pluviométriques que par la fonte des glaciers et du manteau neigeux. Enfin, ils mettent en exergue les unités géographiques et les groupes de population les plus susceptibles d'être affectés par des variations climatiques.
In the Himalayas, where the increase in temperatures is higher than the world average, climate change is expected to impact water resources in a particularly significant manner. Whereas climate specialists using measurements and simulations play down this statement by underlining uncertainties and differences between the west and east of the range, the media and development agencies tend to paint a uniform picture of a water shortage now and in the future. As part of an interdisciplinary programme (glaciology, hydrology, agronomy, geography) in the Koshi basin in Nepal, we discuss these remarks, while stressing the need to distinguish between situations according to the geographical units and to take into account the cultural, social and economic context when addressing this subject. The investigations that we carried out at four fieldwork sites, which are representative of Nepalese milieus, aimed to find out whether populations noticed any variations in water resources that affected their practices (farming, livestock breeding, tourism) and if they attributed them to climate change. Our results show contrasting situations and changes in practices with no obvious connection to the climate. Among other things, they provide information about snow, a parameter that has been measured incorrectly and underestimated in simulations, and they show that populations are more affected by fluctuations in rainfall patterns than by the melting of glaciers and the snow cover. Lastly, they highlight the geographical units and population groups most likely to be affected by climatic variations.
Climate change and water resources in the Himalayas - Joëlle Smadja, Olivia Aubriot, Ornella Puschiasis, Thierry Duplan, Juliette Grimaldi, Mickaël Hugonnet, Pauline Buchheit
In the Himalayas, where the increase in temperatures is higher than the world average, climate change is expected to impact water resources in a particularly significant manner. Whereas climate specialists using measurements and simulations play down this statement by underlining uncertainties and differences between the west and east of the range, the media and development agencies tend to paint a uniform picture of a water shortage now and in the future. As part of an interdisciplinary programme (glaciology, hydrology, agronomy, geography) in the Koshi basin in Nepal, we discuss these remarks, while stressing the need to distinguish between situations according to the geographical units and to take into account the cultural, social and economic context when addressing this subject. The investigations that we carried out at four fieldwork sites, which are representative of Nepalese milieus, aimed to find out whether populations noticed any variations in water resources that affected their practices (farming, livestock breeding, tourism) and if they attributed them to climate change. Our results show contrasting situations and changes in practices with no obvious connection to the climate. Among other things, they provide information about snow, a parameter that has been measured incorrectly and underestimated in simulations, and they show that populations are more affected by fluctuations in rainfall patterns than by the melting of glaciers and the snow cover. Lastly, they highlight the geographical units and population groups most likely to be affected by climatic variations.
Dynamique de la neige de culture dans les Alpes Françaises - Pierre Spandre, Hugues François, Samuel Morin, Emmanuelle George-Marcelpoil
Le développement de la neige de culture dans les Alpes françaises a réellement démarré dans les années 1990. Devenue une garantie de réussite de leur séjour pour les skieurs comme de résultat pour les exploitants, la neige de culture s'est systématisée. Les problématiques liées au changement climatique ont justifié depuis plusieurs années les investissements dans les enneigeurs et suscité l'intérêt pour des études scientifiques croisant des approches physiques et socio-économiques dans lesquelles nous inscrivons ce travail.Notre enquête a été réalisée à l'automne 2014 sur la base d'un panel représentatif de domaines skiables et a révélé un taux d'équipement des pistes en neige de culture de 32 % en surface dans les Alpes françaises. Les stations Moyennes à Très Grandes sont actuellement équipées de manière similaire. La tendance à l'équipement s'est renforcée ces dernières années et la surface équipée dépassera 40 % dès 2020 d'après les résultats de notre enquête. Toutefois, la dynamique de développement de la neige de culture est variable selon les stations. Leur projet d'extension est fortement lié à leur taille et les Très Grandes Stations devraient être les plus équipées en enneigeurs en 2020 (près de 50 % en surface).Une analyse des conditions climatiques alpines montre pourtant que le potentiel de production est limité et décline depuis les années 1960. Produire de la neige de culture est coûteux et le sera de plus en plus à mesure que le besoin se rapproche du potentiel de production et que la poursuite des effets du changement climatique pousse les domaines à produire dans des conditions marginales.
Snowmaking facilities have been commonplace in the French Alps since 1974 and particularly since the 1990s. Now, nearly all resorts are equipped with snowmaking facilities, which guarantee snow for skiers and sufficient revenue for resorts. The effects of climate change have justified recent investments in new facilities, and research efforts are beginning to combine socio-economic and physically-based approaches. We carried out a survey in autumn 2014, collecting data from a representative sample of resorts in the French Alps. We found that 32% of maintained ski slope areas in the French Alps are now equipped with snowmaking facilities; our findings indicate that this proportion is likely to reach 43% by 2020, with most of the increase in “Very Large” resorts. Although “Medium” to “Very Large” resorts are currently equipped at similar levels, the projected development varies with resort size. “Very Large” resorts are planning the largest growth, with nearly 50% of their ski slopes equipped with snowmaking facilities by 2020. However, our analysis reveals a limited potential for snowmaking in the French Alps: since the 1960s, suitable conditions have decreased by several hours per year. Since the effects of climate change are expected to increase in the coming decades (all scenarios suggest an air temperature increase), ski resorts will have to produce snow in less ideal conditions, incurring greater costs as a result of decreased production efficiency.
Snowmaking in the French Alps - Pierre Spandre, Hugues François, Samuel Morin, Emmanuelle George-Marcelpoil
Snowmaking facilities have been commonplace in the French Alps since 1974 and particularly since the 1990s. Now, nearly all resorts are equipped with snowmaking facilities, which guarantee snow for skiers and sufficient revenue for resorts. The effects of climate change have justified recent investments in new facilities, and research efforts are beginning to combine socio-economic and physically-based approaches. We carried out a survey in autumn 2014, collecting data from a representative sample of resorts in the French Alps. We found that 32% of maintained ski slope areas in the French Alps are now equipped with snowmaking facilities; our findings indicate that this proportion is likely to reach 43% by 2020, with most of the increase in “Very Large” resorts. Although “Medium” to “Very Large” resorts are currently equipped at similar levels, the projected development varies with resort size. “Very Large” resorts are planning the largest growth, with nearly 50% of their ski slopes equipped with snowmaking facilities by 2020. However, our analysis reveals a limited potential for snowmaking in the French Alps: since the 1960s, suitable conditions have decreased by several hours per year. Since the effects of climate change are expected to increase in the coming decades (all scenarios suggest an air temperature increase), ski resorts will have to produce snow in less ideal conditions, incurring greater costs as a result of decreased production efficiency.