The endophyte Allantophomopsis cytisporea is associated with snow blight on Calluna vulgaris in the Alps—An effect of climate change?

The European Alps have experienced remarkable climate changes since the beginning of the Industrial Age. In particular, mean air temperature in the region increased at a greater rate than global temperature, leading to the loss of nearly half of the glaciated area and to important changes in the ecosystems. Spanning 1,200 km in length, with peaks reaching over 4,000 meters above sea level (m asl), the Alps have a critical influence over the weather in most of Europe and separate the colder oceanic/continental climate in the north from the milder Mediterranean climate in the south. The climatic differences between the main slopes are reflected into different climate changes—whereas the northern slope got wetter, the southern slope got drier. The consequences of these climate changes are not confined to the Alpine region. Being located in the center of Europe, the Alps provide water and electricity for over 100 million people. Alpine run-off is a major contributor to the total discharge of several major European rivers such as the Rhine, the Rhône, the Po, and the Danube. Therefore, climate change in the Alps can have significant economic impacts on a continental scale. Their convenient geographical position allowed scientists to study the Alpine climate since the very beginning of the instrumental era. The first instrumental meteorological observations in an Alpine valley were taken as early as the mid-17th century, soon followed by measurements at higher elevations. Continuous records are available since the late 18th century, providing invaluable information on climate variability to modern-day researchers. Although there is overwhelming evidence of a dominant anthropogenic influence on the observed temperature increase, the causes of the changes that affected other variables have, in many cases, not been sufficiently investigated by the scientific community.

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Winter tourism under climate change in the Pyrenees and the French Alps: relevance of snowmaking as a technical adaptation

The Cryosphere ◽

10.5194/tc-13-1325-2019 ◽

2019 ◽

Vol 13 (4) ◽

pp. 1325-1347 ◽

Cited By ~ 8

Author(s):

Pierre Spandre ◽

Hugues François ◽

Deborah Verfaillie ◽

Marc Pons ◽

Matthieu Vernay ◽

...

Keyword(s):

Climate Change ◽

Climate Projections ◽

Reference Period ◽

Winter Tourism ◽

French Alps ◽

Ski Resorts ◽

The Alps ◽

Natural Snow ◽

Snow Conditions ◽

Near Future

Abstract. Climate change is increasingly regarded as a threat for winter tourism due to the combined effect of decreasing natural snow amounts and decreasing suitable periods for snowmaking. The present work investigated the snow reliability of 175 ski resorts in France (Alps and Pyrenees), Spain and Andorra under past and future conditions using state-of-the-art snowpack modelling and climate projections using Representative Concentration Pathways RCP2.6, RCP4.5 and RCP8.5. The natural snow reliability (i.e. without snowmaking) elevation showed a significant spatial variability in the reference period (1986–2005) and was shown to be highly impacted by the ongoing climate change. The reliability elevation using snowmaking is projected to rise by 200 to 300 m in the Alps and by 400 to 600 m in the Pyrenees in the near future (2030–2050) compared to the reference period for all climate scenarios. While 99 % of ski lift infrastructures exhibit adequate snow reliability in the reference period when using snowmaking, a significant fraction (14 % to 25 %) may be considered in a critical situation in the near future. Beyond the mid-century, climate projections highly depend on the scenario with either steady conditions compared to the near future (RCP2.6) or continuous decrease in snow reliability (RCP8.5). Under RCP8.5, our projections show that there would no longer be any snow-reliable ski resorts based on natural snow conditions in the French Alps and Pyrenees (France, Spain and Andorra) at the end of the century (2080–2100). For this time period and this scenario, only 24 resorts are projected to remain reliable with snowmaking, all being located in the Alps.

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Carbon flux response and recovery to drought years in a hemi-boreal peat bog between different vegetation types

10.5194/egusphere-egu2020-13187 ◽

2020 ◽

Author(s):

James Benjamin Keane ◽

Sylvia Toet ◽

Phil Ineson ◽

Per Weslien ◽

Leif Klemedtsson

Keyword(s):

Climate Change ◽

Plant Traits ◽

Net Ecosystem Exchange ◽

Calluna Vulgaris ◽

High Water ◽

Future Climate ◽

Peat Bog ◽

Blanket Bog ◽

Drought Conditions ◽

Ghg Fluxes

Peatlands are a globally important store of approximately 500 Gt carbon (C), with northern blanket bogs accumulating ca. 23 g C m-2 y-1 from undecomposed organic material due to prevailing cool wet conditions. As a sink of carbon dioxide (CO2) they act as an important brake on anthropogenic climate change, but in the warming climate the likelihood of drought will increase. However, it is unknown how drought will affect the GHG balance of peatlands: dryer, warmer conditions will likely reduce net ecosystem exchange (NEE) of CO2 and increase soil respiration, potentially tipping these landscapes from sinks to sources of C. High water tables mean blanket bogs are major source of methane (CH4), an important greenhouse gas (GHG) with a global warming potential (GWP) 34 times that of CO2 over 100 years, but this may change in the future climate. It is further expected that the changing climate will alter blanket bog species composition, which may also influence the GHG balance, due to differences in plant traits such as those which form aerenchyma, e.g. Eriophorum vaginatum (eriophorum) and non-aerenchymatous species, e.g. Calluna vulgaris (heather). In order to understand how these important C stores will respond to climate change, it is vital to measure GHG responses to drought at the species level. &#160;&#160;We used an automated chamber system, SkyLine2D, to measure NEE and CH4 fluxes near-continuously from an ombrotrophic blanket peat bog. Five general ecotypes were identified: sphagnum (Sphagnum spp), eriophorum, heather, water and mixtures of species, with five replicates of each sampled. We followed the fluxes of CO2 throughout 2017- 2019 and CH4 throughout 2017- 2018, hypothesising that GHG fluxes would significantly differ between ecotypes. In 2018, the bog experienced drought conditions, allowing the comparison of NEE between drought and non-drought years, and the potential to recover the following year. Contemporaneous measurements of environmental variables were collected to infer details regarding the drivers of GHG fluxes.We found significant differences in CH4 emissions between ecotypes, F= 2.71, p< 0.02, ordered high to low: eriophorum > sphagnum > water > heather> mix, ranging from ca. 1.5 mg CH4-C m-2 d-1 to 0.5 mg CH4-C m-2 d-1. There were no significant differences in NEE between ecotypes, F= 0.54, p> 0.7, however, under 2018 drought conditions all ecotypes were net sources of CO2. We will also present NEE from 2019, when precipitation levels returned to typical conditions. Our results indicate that drought and shifts in vegetation composition under future climate may alter the C balance of hemi-boreal and potentially act as a positive feedback to climate change in a long-term scenario.

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Sediment discharge from alpine glaciers in times of increased melt – an example from the Austrian Alps

10.5194/egusphere-egu2020-19789 ◽

2020 ◽

Author(s):

Jan-Christoph Otto ◽

Vinzenz Walk ◽

Erwin Heine ◽

Markus Keuschnig

Keyword(s):

Climate Change ◽

Sediment Dynamics ◽

Sediment Discharge ◽

Climate Conditions ◽

Sediment Budgets ◽

Lake Formation ◽

Summer Temperatures ◽

The Alps ◽

Ground Penetrating ◽

Delta Sediments

Glaciated mountains are zones of high sediment dynamics and at the same time very sensitive to climate change. In times of increased summer temperatures and high melt rates have been related to observed increase in sediment dynamics at various locations. However, this response seems to be highly variable also on regional scales indicating that controlling factors have yet not been fully identified and understood. Sediment output from glaciated catchments affects sediment budgets, streamflow ecology and hydropower generation. Data on sediment discharge from proglacial areas in the Alps is scarce. Knowledge on sediment responses to increasing temperatures and changing climates is crucial for river and reservoir management and climate change adaptation.We contribute to this debate by quantifying sediment discharge from the Obersulzbachkees glacier, Hohe Tauern, Austria based on recent lake deposition volume. Located at the valley head of the Obersulzbach valley, the glacier experienced rapid degradation within the last 20 years and also showed high rates of sediment discharge. The formerly large single glacier disintegrated into five remaining parts and a large proglacial lake formed. Sediment discharge from these smaller glaciers is captured by the lakes and a huge delta has developed after retreat of ice from the lake. We quantified the lake and delta sediments using ground penetrating radar and sub-bottom profiling and revised our previous estimations by including new data increasing the accuracy of our finding. The Obersulzbachkees retreated by 400-800 m in distance between 1999 and 2019 and lost more than 3 km&#178; of glacier area. Between 2007 and 2019 more than 600,000 m&#179; of sediments have been deposited within the lake delta only. We discuss sediment discharge from glacier to lake in relation to glacier retreat and climate conditions since lake formation and relate our findings to both changes in the catchment and runoff and sediment output dynamics from the lake.

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Estimating future changes in Alpine flash floods using CP-RCM projections

10.5194/egusphere-egu2020-9263 ◽

2020 ◽

Author(s):

Frederiek Sperna Weiland ◽

Pety Viguurs ◽

Marjanne Zander ◽

Albrecht Weerts

Keyword(s):

Climate Change ◽

High Resolution ◽

Climate Models ◽

Regional Climate ◽

Flash Floods ◽

Climate Prediction ◽

Alpine Region ◽

Parameter Estimates ◽

Projection System ◽

The Alps

Flash floods are a significant natural hazard in the Alpine region (FOEN, 2010). With changing rainfall regimes and decreased snow accumulation due to climate change, the risk of flash flood occurrence and timing thereof could change as well (Etchevers et al., 2002).In this study the frequency and occurrence of flash floods in the Alpine region is estimated for current and future climate (RCP8.5) using state-of-the-art high-resolution convection permitting climate models (CP-RCMs). For the historical period and far future (2100), data from an ensemble of convection permitting climate models (Ban et al., submitted 2019) was used to drive a high-resolution distributed hydrological model, i.e. the wflow_sbm model (Imhoff et al., 2019, Verseveld et al., 2020). The model domains cover the mountainous parts of the Danube, Rhone, Rhine and Po located in the Alps. &#160;The CP-RCM time-series available are of limited length due to computational constrains. At the same time the locations of flash floods vary per year therefore a regional scale analysis is made to assess whether in general the severity, frequency and timing of flash floods in the Alps will likely change under changing climate conditions.This research is embedded in the EU H2020 project EUCP (EUropean Climate Prediction system) (https://www.eucp-project.eu/), which aims to support climate adaptation and mitigation decisions for the coming decades by developing a regional climate prediction and projection system based on high-resolution climate models for Europe.References:Etchevers, P., Golaz, C., Habets, F., and Noilhan, J., Impact of a climate change on the Rhone river catchment hydrology, J. Geophys. Res., 107( D16), doi:, 2002. Federal office for the environment FOEN (2010) Environment Switzerland 2011, Bern and Neuchatel 2011. Retrieved from www.environment-stat.admin.chImhoff, R.O., W. van Verseveld, B. van Osnabrugge, A.H. Weerts, 2019. Scaling point-scale pedotransfer functions parameter estimates for seamless large-domain high-resolution distributed hydrological modelling: An example for the Rhine river. Submitted to Water Resources Research, 2019.N. Ban, E. Brisson, C. Caillaud, E. Coppola, E. Pichelli, S. Sobolowski, &#8230;, M.J. Zander (submitted 2019): &#8220;The first multi-model ensemble of regional climate simulations at the kilometer-scale resolution, Part I: Evaluation of precipitation&#8221;, manuscript submitted for publication.

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