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FS 3.135

Recent advances in the Elevation-Dependent Climate Change in global mountains

Details

  • Full Title

    FS 3.135: Elevational stratification of climate change: impacts and driving mechanisms in global mountain ecosystems
  • Scheduled

    TBA
  • Location

    TBA
  • Assigned to Synthesis Workshop

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  • Thematic Focus

    Atmosphere, Cryo- & Hydrosphere, Ecosystems, Water Cycle
  • Keywords

    Elevation-Dependent Climate Change, Elevation-Dependent Warming

Description

Numerous studies have shown that climate change varies significantly with elevation, a phenomenon known as Elevation-Dependent Climate Change (EDCC). Research, originally focused on Elevation-Dependent Warming, has expanded beyond temperature variations leading to the broader concept of EDCC. Elevational stratification of trends in key climate variables (e.g. precipitation, wind, humidity, cloud) often results from complex mechanisms such as those controlling atmospheric stability and surface energy balance, orographic precipitation and intensification of the hydrological cycle. This session invites studies which use in-situ observations, remote sensing, and model simulations to examine elevational stratification of climate change and related phenomena (e.g., snow cover, wind patterns, hydrological cycles) in mountainous regions. Since EDCC has been investigated across different regions and assessed through various statistical methods, studies which compare different mountain regions of the world or examine results from the same region, but using different approaches, are particularly welcome. Comparisons between different datasets, showcasing their distinct advantages and limitations, can help understand the complex nature of EDCC. EDCC influences and is influenced by multiple climate variables ranging across the atmosphere, hydrosphere, cryosphere, and biosphere. Studies which attempt to understand such interactions are encouraged, as they drive key ecological transformations (e.g. upward migration of treelines/snowlines), which are reshaping mountain ecosystems. Particular focus on the underlying mechanisms which may be responsible for such changes is of great interest

Submitted Abstracts

ID: 3.8140

Future Elevation-Dependent Climate Changes in the European Alps and Possible Links with Surface Temperature: Insights from the EURO-CORDEX Ensemble

Anna Napoli
Matiu, Michael; Kotlarski, Sven; Zardi, Dino; Bellin, Alberto; Majone, Bruno

Abstract/Description

Predicting future climate changes in mountainous regions poses substantial challenges due to the intricate nature of local weather and climate dynamics. Moreover, mountains undergo changes that are specific to each region, calling for a localized approach to the analysis of the underlying phenomena. In recent decades, there has been considerable focus on elevation-dependent warming and its future projections, but other variables have received less attention. A thorough understanding of the drivers and the relationships among different patterns requires detailed analyses of models’ output alongside key atmospheric and surface variables.
This study focuses on the European Alpine Region, leveraging the extensive EURO-CORDEX ensemble to examine elevation-dependent changes detectable in 19 climate variables. Our findings highlight pronounced elevation-dependent patterns during winter and spring for minimum temperature, diurnal temperature range, and specific humidity. Strong correlations are evident between surface temperature and other variables such as diurnal temperature range, minimum temperature, specific humidity, and longwave downward radiation. Moreover, variables significantly influenced by model parameterization, such as heat fluxes and snow cover fraction, show minimal coherence within the ensemble. These findings underline the critical importance of using an ensemble-based approach when crafting climate scenarios to inform future adaptation strategies.

ID: 3.8613

Revisiting Observed Elevation-Dependent Warming in Switzerland

Simon Scherrer
Kotlarski, Sven

Abstract/Description

Switzerland with its pronounced topography and the availability of long-term, high-resolution and high-quality data sets is an ideal testbed for analyzing elevation-dependent climate change. Here, we revisit the trends in Swiss temperature and sunshine duration over the period 1951–2024 using MeteoSwiss’ long-term consistent monthly temperature and sunshine duration gridded data sets at 2 km resolution. We compare the results with those derived from two versions of the E-OBS data set and the ERA5-Land reanalysis, all of them at 0.1° resolution. The MeteoSwiss temperature grid shows increasing temperature in all months and across all elevations. Distinct elevational differences emerge in spring and from September through January. The increased spring warming at medium elevations is likely driven by snow-albedo feedback. The stronger autumn-winter warming at low elevations is linked to a strong increase in sunshine duration at low elevations which is probably partly related to a decrease in the fog and low stratus (FLS) frequency. Both E-OBS versions also show increasing temperatures across all months and elevations. However, while the recent E-OBS v30.0e fails to capture the main elevational differences in spring and from September through January, the extended homogenized E-OBS version (v19eHOM) reproduces these differences with remarkable accuracy. ERA5-Land also warms across all months and elevations. It reproduces the enhanced spring warming at medium elevations but overestimates the effect. It fails to capture the stronger autumn-winter warming at low elevations, likely due to an inadequate FLS representation. Our results underscore that long-term, consistent climate data sets that resolve small-scale features are essential for reliable trend detection, especially for an accurate quantification of elevation-dependent warming at local scales.

ID: 3.9211

Modelling the relationship between MODIS land surface temperature and in situ air temperature on Mount Kilimanjaro: exploring temperature variability and trends across environmental factors

Yaping Mo
Pepin, Nick; Lovell, Harold

Abstract/Description

Mount Kilimanjaro, the highest peak in Africa (5895 m), rises from the lowland savannah of northern Tanzania. Being near the equator, it includes a wide range of ecological zones from tropical savannah to ice/snow (nival zone) near the summit. Kilimanjaro therefore serves as a critical indicator of climate change in equatorial regions. Studies have found increased warming on Kilimanjaro at higher elevations, known as elevation-dependent warming (EDW). These temperature changes lead to melting snow and shrinking glaciers, threatening the unique ecosystems and water resources. However, due to the sparse distribution of high-elevation weather stations, there is limited understanding of temperature patterns and the drivers of change. One approach to address this limitation is the use of satellite-derived land surface temperature (LST), which has a strong relationship with air temperature (Tair) and offers good coverage even in complex mountainous terrain. However, LST and Tair differ in their physical definitions, measurement methods, and responses to environmental conditions. In complex mountainous regions like Kilimanjaro, LST alone cannot well model Tair. Understanding how environmental factors influence the LST-Tair relationship is therefore essential for improving temperature models and assessing EDW. This study examines the modelling of Tair from Moderate Resolution Imaging Spectroradiometer (MODIS) LST on Mount Kilimanjaro from 2004 to 2024, incorporating elevation, topography, land cover (particularly vegetation and snow) and solar radiation as auxiliary predictors. In situ Tair data from 26 sites, covering elevations from 991 m to 5803 m is used to develop and validate models, and discuss the environmental factors influencing the LST-Tair relationship. Our results show that the LST-Tair relationship is more variable during the day, with a pronounced positive temperature difference (ΔT, LST minus Tair). Additionally, ΔT increases at higher elevations. Finally, temperature trends based on the calibrated LST data are analysed to determine whether EDW is evident and how trends vary with elevation, aspect, vegetation and snow.

ID: 3.10197

Existing observations and new transects for elevation-dependent climate change detection in the Pyrenees

Pere Esteban Vea
López-Moreno, Juan Ignacio; Prohom Duran, Marc; Cunillera Graño, Jordi

Abstract/Description

Since climate change appears to be more pronounced at higher altitudes, several efforts have been made to quantify its effects in mountain regions. Thanks to these initiatives, it has been observed that the rate of climate change is often more rapid at higher elevations, as highlighted by various studies worldwide and by the Elevation-Dependent Climate Change (EDCC) working group. At the same time, active research has been conducted in the Pyrenees, primarily focusing on temperature and precipitation trends since the 1950s. However, as in other mountain regions worldwide, the lack of data from the highest elevations still prevents researchers from drawing solid conclusions about the existence of EDCC in this southwestern European mountain range. To address this issue, and as part of the LIFE-SIP project Pyrenees4Clima (2024–2032), various tasks have been planned for the detection and analysis of EDCC, mainly focusing on temperature and relative humidity. First, as many Andorran, Spanish, and French climate records as possible from elevations above 1,500 meters are being compiled, with quality control, homogenization (if needed), and trend analysis being carried out. Furthermore, two or three new transects with meteorological sensors are expected to become operational during summer–autumn 2025 in the central Pyrenees (Bonabé, Benasque, and Torla areas), where the highest elevations of the range are located. These transects will follow, as closely as possible, the Unified High Elevation Observing Platform (UHOP) recommendations regarding the placement of Anchor, Intermediate, and Float stations. Using the data compiled before and during the coming years, analyses for EDCC detection will be conducted. Additionally, the dependence on circulation patterns and the influence of snow cover (or its absence) on warming will also be explored. This presentation aims to introduce IMC 2025 participants and EDCC specialists to the new transects and to share experiences and recommendations for future work.

ID: 3.10214

Assessment of the elevation-dependent climate change in the Extended European Alpine Region over 1961-2020 based on the EEAR-Clim dataset

Giulio Bongiovanni
Napoli, Anna; Matiu, Michael; Crespi, Alice; Majone, Bruno; Zardi, Dino

Abstract/Description

The Alpine area is one of the most vulnerable and sensitive regions to the continuous warming of climate and it is considered an important hotspot of climate change. In particular, climate change is expected to exert a strong influence on all components of the hydrological cycle, including river regimes, with consequent effects on the services offered by the freshwater ecosystem, as well as on water availability for users, thus affecting several socio-economic sectors. Climate change assessment in the Alpine region relies on direct application of climate observations and, thus, their quality may strongly impact climate and hydrological studies results and predictions in terms of reliability, accuracy and precision. Here, we present an extended climatological and trend analysis of key climate variables for the Extended European Alpine Region (EEAR) over the 1961-2020 period. The analysis exploits the recently developed observational dataset EEAR-Clim, addressing the key issues in terms of spatial density, data quality, time resolution and completeness. Climatological and trend analysis was carried out on different time scales considering both mean values and a selection of ETCCDI indices. The key goal of such analysis is the robust assessment of phenomena related to elevation-dependent warming (EDW) and precipitation change (EDPC). A further analysis concerned the relationship between observations and the main teleconnection patterns influencing the Alpine climate. The present study aims to provide a reliable analysis of the evolution of key climate variables in the Alpine region. Being a study based on the most comprehensive spatial coverage in this area to date, the related results significantly increase the amount of information available to involved stakeholders to prevent and quickly plan for disaster management, risk mitigation and formulating proper locally relevant adaptation strategies.

ID: 3.10298

Elevation-Dependent Effects of Climate Change on Snowpack in Spanish Mountains

Juan Ignacio Lopez Moreno
Deschamps Berger, Cesar; Revuelto, Jesús; Alonso-González, Esteban

Abstract/Description

Climate change is expected to reduce both, snow accumulation and its duration on the ground in most temperate mountain regions. Generally, it is assumed that the reduction in snow cover will be more pronounced in lower-elevation areas and will progressively moderate at higher elevations. This is because sensitivity to warmer temperatures increases as an area gets closer to the 0ºC winter isotherm. However, factors such as the hypsometry of mountain areas, slope aspects, the temporal distribution of snowfalls during the winter and spring seasons, and the combined influence of projected changes in temperature and precipitation add significant complexity to this elevation-dependent pattern. This study investigates the elevation effect on snowpack changes using high-resolution simulations of the snow mass and energy balance in Spain’s national parks (NPs). These parks are distributed across various mountain ranges, including the Pyrenees (Ordesa y Monte Perdido and Aigües Tortes NPs), the Cantabrian Mountains (Picos de Europa NP), the Central System (Guadarrama NP), Sierra Nevada, and El Teide NPs. They span a wide latitudinal gradient (42º to 28ºN) and exhibit a diverse range of climatological and hypsometric characteristics. Simulations were performed for RCP 2.6, 4.5, and 8.5 scenarios for the 2050 time horizon. A general reduction of the snow cover is expected but snow remains at the highest elevation of all NPs. The Central System, Sierra Nevada, and El Teide mountain ranges have the most vulnerable snowpacks and will endure the largest reductions. Across all sites, the decrease in snow cover is most pronounced at lower elevations, but significant differences are observed in the gradient slope and the effect of slope aspects. The presentation will aim to disentangle the effects of the initial snowpack characteristics, of the local climate, and of the precipitation and temperature changes on the difference in snowpack evolution between NPs.

ID: 3.10627

On the impact of secondary aerosols over the elevation dependent climate change in the Western Himalayas

Tanmay Dhar

Abstract/Description

There are complex interactions between different sources of aerosols, particularly in mountainous regions. And also, how these aerosols can influence atmospheric processes like precipitation, glacier melting, and more, are intriguing. The combined effects of aerosols from local and long-range sources have a stronger impact than individual sources, particularly when secondary aerosols are considered. Secondary aerosols are playing substantial role on elevation dependent climate change in the Western Himalayas. The aim of this study is to dynamically monitor the behavior of secondary aerosol spatially and temporally over the region of our concern. Also, considering the influence of secondary aerosols specifically towards the elevation dependent warming trend in relation to their abundance and source characteristics, this study aims to refine the local characteristics of secondary aerosol through thorough study of dynamics of local microclimates.

ID: 3.10712

Upward migration of snowline in the Alps and impact on Elevation-Dependent Warming in MAR simulations over 1961-2100

Ian Castellanos
Ménégoz, Martin; Blanchet, Juliette; Beaumet, Julien

Abstract/Description

Mountain regions exhibit specific regional imprints when it comes to climate change. The presence of snow plays a role in this imprint and adds a strong seasonality to the observed changes. This study aims to understand the processes that link Elevation-Dependent Warming to the upward migration of the snowline, by investigating the surface energy balance in the Alps through the seasons. Combining three MAR (Modèle Atmosphérique Régional) simulations with a 7kmx7km resolution over 1961-2100 and under different climate scenarios, the change in albedo due to the upward migration of the snowline and the energy used to melt snow are found to be major drivers in the patterns of EDW simulated by MAR in the Alps.

ID: 3.11100

Assessing climate variability with a high resolution reanalysis over High Mountain Asia

Santolaria-Otin Maria
Amory, Charles; Faïn, Xavier; Ménégoz, Martin; Brun, Fanny; Mayer, Christoph; Lambrecht, Astrid

Abstract/Description

High-elevation regions with complex orography pose major challenges for estimating local precipitation and snow-related variables due to sparse observations and strong spatial variability. To bridge this gap, the Modèle Atmosphérique Régional (MAR) has been used to generate a high-resolution, century-long atmospheric reanalysis over High Mountain Asia spanning 1900 to the present. The model has been calibrated using both local meteorological observations and remote sensing, and is driven by global reanalyses, including ERA5 (1950–present) and ERA-20C (1900–2010) to achieve a comprehensive coverage of the 20th century. This centennial atmospheric reanalysis provides unprecedented insights into interannual variability, long-term trends, and the links between large-scale atmospheric circulation and local climatic conditions, including elevation contrasts. Its fine spatial resolution significantly serves to improve our understanding of cryosphere-climate interactions and supports a wide range of applications in High Mountain Asia.

ID: 3.11274

Monitoring meteorology and snow in mountains across elevational gradients in northeast Appalachian Mountains in North America.

Joshua Benes
Beauharnois, Mark; Bomblies, Arne; Broccolo, Jay; Burakowski, Elizabeth ; Casson, Paul; Clemins, Patrick ; Contasto, Alix; Dondeti, Vamsi; Garret, Keith; Lane, Sara ; Lineman, Braedon; McKim, Scott; Minder, Justin; Morris, Colby ; Murray, Georgia ; Nadeau, Chris; Nelson, Sarah

Abstract/Description

A new regional partnership in the northeast United States is focused on monitoring mountains at different elevational gradients to support prediction of extreme weather events and contribute to the Unified High Elevation Observing Platform (UHOP) to enhance understanding of climate change. The partnership includes the State University of New York’s Atmospheric Sciences Research Center (Whiteface Mountain Observatory in New York’s Adirondack Mountains), the University of Vermont Summit to Shore Environmental Observation Network, and the Mount Washington Observatory in New Hampshire (a nonprofit internationally known for extreme weather monitoring). The region has also been developing a feasibility study for a regional snow monitoring network called the Northeast Snow Survey (NESS) funded through the US Department of Agriculture Natural Resources Conservation Service. This study is working to explore the development of a regional snow monitoring network and will focus on the need of monitoring weather and snow conditions across the region at different elevations. This session will explore these initiatives and how they can be leveraged to monitor climate and enhance prediction of extreme weather dynamics across the northeast Appalachian Mountain region.

ID: 3.11473

Summer intense precipitations in the Alpine region: altitudinal effects

Matteo Borgnino
Ferguglia, Olivia; Palazzi, Elisa; Pasquero, Claudia

Abstract/Description

Mountain regions are highly vulnerable to climate change. While Elevation-Dependent Warming has been extensively documented in various mountainous areas worldwide, fewer studies have explored how other climate variables, especially precipitation and its extremes, vary with elevation over time. In this study, we investigate changes in summer mean and intense precipitation over the Greater Alpine Region using different gridded datasets from reanalysis, rain gauges and satellite products. By applying various indices and metrics to identify mean, extreme precipitation and its frequency, we analyse how these quantities have changed in the last decades and their elevation-dependent variations. In particular, our findings indicate that intense summer precipitation has increased over recent decades, with a more pronounced enhancement over the Alpine slopes compared to the Po Valley. Moreover, when sub-daily data are available, our analysis suggests that sub-daily duration precipitation extremes may exhibit even stronger signals.

ID: 3.11730

The response of two inverted tree lines under possible elevational-dependent warming: Southern Sierra Nevada, California USA

Louis Scuderi

Abstract/Description

Elevational-Dependent Warming (EDW) implies that mountain warming rates may exceed those found in non-mountainous environments with possible systematic differences expressed as an increase in warming rates with elevation. Temperature profiles across inverted tree lines in mountainous environments are opposite of the normal elevational trend with temperatures increasing above the cold air pool. One consequence of elevation dependent warming in mountain environments is a potential for a reduction of temperature inversions in cold air pools as both the cold air pool and surrounding higher terrain warm at different rates possibly resulting in a decrease in inversions in both depth and intensity due to greatly increased temperatures in the cold air pool. Few long-term profiles of cold air pool/inverted tree line boundaries exist. Because this ecotone boundary is typically below the resolution of satellite sensors there is a need for in situ monitoring. Here we investigate the change in temperature along two adjacent inverted tree lines in California’s southern Sierra Nevada oriented in opposite directions on north and south facing slopes. A combined canopy and soil temperature sensor transect across the two inverted tree line boundaries and cold pools monitored since 2006 shows a decrease in temperature inversions and intensity over time associated with significant warming of the cold air pool. Annual canopy temperatures increased for all sites on south facing slopes and meadow cold air pockets while decreasing on average for north facing slopes. Normally, temperature inversions at night occur in all months, however the study site shows a disappearance of nighttime inversions during April and early May, a key time associated with the timing of conifer bud break. This change allows the establishment of seedlings at the meadow edge and the advance of the inverted tree line into the cold pool resulting in an increase in meadow edge albedo which in turn impacts the energy balance and snow cover duration along the ecotone. Areas with cold air pool degradation may be indicative of climate hotspots where temperature increase leads to change in ecosystem function including change in hydrologic response and decreases in biodiversity.

ID: 3.11972

Local climatic drivers of elevation-dependent warming: insights from a concerted field and modeling assessment in an alpine national park

Simon Zitzmann
Fersch, Benjamin; Kunstmann, Harald

Abstract/Description

This study investigates elevation-dependent warming (EDW) in the Alps, focusing on Berchtesgaden National Park, Germany, to provide insights into the drivers of warming patterns and their spatial variability. EDW, a key aspect of Elevation-Dependent Climate Change (EDCC), describes variations in warming trends with altitude, often leading to amplified warming at higher elevations. This phenomenon has critical implications for mountainous and downstream ecosystems and water resources. While mechanisms such as snow-albedo feedbacks and the increased sensitivity of cold, dry regions to climate change are well-documented, the roles of soil interactions and topography remain underexplored.
Our research integrates high-resolution spatial data with long-term temperature records to examine how these factors influence EDW. Using data from HISTALP, a homogenized observational dataset for the Greater Alpine Region, we analyze the relationship between warming trends and topographic features. Within Berchtesgaden National Park, 23 long-term meteorological stations provide climate data, complemented by three temporary stations spanning altitudes from 625 to 1930 m, which monitor surface energy balance components to capture fine-scale variations.
Preliminary findings indicate that EDW is influenced by factors beyond altitude. Historical records (1910–2010) show significant warming trends across elevations (0.4–2.4 K per century) in the Greater Alpine Region, with higher altitudes generally experiencing stronger warming – except in winter, when mid-elevation bands (500–1000 m) warm the most. Slope orientation plays a crucial role, with north-facing slopes exhibiting amplified trends.
Ground heat flux analysis reveals spatial variations likely driven by soil depth and moisture retention. Ongoing research integrates these observational insights with simulations from the GEOtop hydrological model to provide a spatially refined understanding of the surface energy balance and its role in EDW.

ID: 3.12042

Impacts of long-term climate trends and elevation on ant diversity

Abusisiwe Ndaba
Mbanyana-Nhleko, Nokuthula; van Noort, Simon; Janion-Scheepers, Charlene

Abstract/Description

Arthropods provide vital ecosystem services and are important indicators of ecosystem changes as they are sensitive to environmental changes. Recent studies show alarming rates of decline in insect biomass. These declines are mainly attributed to climate change, habitat transformation, pollution, and invasive species. However, studies for Africa have been mainly focused on short-term rather than long-term studies, which are crucial for understanding the key global change drivers affecting arthropod diversity and assemblages over time. Studies suggest that the Fynbos in the Cape Floristic Region (CFR) is likely to be highly sensitive to climate change, and the Fynbos biome, in particular, will lose large areas of its natural vegetation near its northern limits, especially those along the west coast and in the Cederberg mountains. Most conservation policies for the CFR focused on plants and larger animals, while arthropods are underrepresented. For example, although ants are vital for fynbos seed dispersal and are affected by land transformation and climate change, their distribution and taxonomy are understudied in the CFR. This study aims to assess changes in ant assemblages over a 20-year period. A total of 17 altitudinal bands were sampled at 200-m altitudinal intervals across a historical altitudinal transect in the Cederberg Wilderness Area. Four replicates of 10 pitfall traps were laid at every 200-m interval, totaling 680 pitfall traps per season. Vegetation cover and height at each pitfall trap were recorded and soil samples were collected for soil analysis. Temperature was measured using i-buttons from 2002 until 2022. In this talk, we will present the results of changes observed in ant assemblages over 20 years and how different factors shape their distribution along the altitude. This study’s findings will aid in managing and conserving biodiversity in a major biodiversity hotspot that is vulnerable to global change drivers.

ID: 3.12427

Elevation-dependent changes in temperature extremes and possible driving mechanisms in the Greater Alpine Region

Adelaide Losana
Ferguglia, Olivia; Palazzi, Elisa

Abstract/Description

Mountain regions are recognised as climate change hotspots, with strong evidence of Elevation-Dependent Warming (EDW), i.e., a stratification of warming rates with elevation. The key drivers of EDW have been studied using observations and model simulations and are well documented in the literature. However, less attention has been given to how EDW manifests itself when temperature extremes are considered, and to the possible drivers of elevational changes in extreme temperature trends.

This study investigates EDW in temperature extremes in the Greater Alpine Region (GAR, 4-19°E, 43-49°N), using indices of extreme warming or cooling as defined by the Expert Team on Climate Change Detection and Indices (ETCCDI) . The analysis is performed using the ERA5 reanalysis and the observation-based E-OBS dataset, both with a grid resolution of 0.25°, covering the period 1950–2024 and allowing for capturing spatial variability across different geographical subregions of the GAR. Our analysis shows that ETCCDI indices related to warm and cold temperature extremes exhibit different behaviors when looking at the elevational stratification of their trends suggesting different mechanisms that have been investigated as potential drivers.

ID: 3.12801

Twenty years of climate trends along a 5000 m elevational-transect across Kilimanjaro from savannah to ice-fields: evidence of elevation-dependent warming

Nicholas Pepin
Mo, Yaping

Abstract/Description

Kilimanjaro (5895 m) is the largest free-standing mountain in Africa, famous for its diminishing snow and ice cover. There are strong linkages between ecosystems on the lower slopes (below 2500 m) and moisture availability higher up the mountain. Every day the strong equatorial sun heats the mountain, causing winds to rise upwards from the rainforest and form clouds/precipitation. At the highest elevations this adds snow to ice-fields, but lower down it provides river runoff for extensive agriculture in the cultivated belt below the rainforest. Unfortunately, long-term warming, along with local land-cover change (including deforestation), has led to drying over recent decades, rapid retreat of the summit ice, depression of the treeline, and several strong forest fires. The research team has operated a transect of 22 weather stations across the mountain from south-west to north-east since 2004. This is now the longest running transect to cover such a wide elevation range (~5000 m) in the world. It extends from savannah, through cultivated land and rainforest, up to the giant heather zone, alpine desert and summit ice cap. Thus, it offers critical information on how linkages between ecological zones are functioning in a warming world and on patterns of elevation-dependent climate change (where mountains warm at different rates to lower elevations). Analysis of two decades of temperature trends (2004-2025) shows an intensification of warming rate with elevation such that the highest sites are warming about twice as rapidly as some sites lower down the mountain. Humidity trends are more variable with both wetting and drying being observed in different locations. There are also contrasts between the two slopes, with the north-east side being much warmer and drier than the south-west slope for the same elevation. Kilimanjaro is a great field laboratory for understanding mountain geography because of its large elevation range, diversity of ecological zones, its local water supply importance and the population pressures on its lower slopes. Understanding local drivers of the elevation stratification of climate changes in this case (snow loss, forest expansion/contraction, cloud changes along slopes) can also be applied to mountains elsewhere.

ID: 3.13096

Extreme precipitation in the Greater Alpine Region: a CMIP6 and EURO-CORDEX model view

Mirsada Cravero
Ferguglia, Olivia; Palazzi, Elisa; Arnone, Enrico

Abstract/Description

Under recent climate change, the Greater Alpine Region (GAR) is experiencing an increase in the intensity and frequency of meteoclimatic extreme events. In particular, precipitation extremes are of primary importance, given their role in defining mountain hydrological resources and triggering geo-hydrological hazards, including downstream impacts. In areas with complex orography, it is crucial to assess how such extremes and their temporal changes are stratified with elevation.
In this study, daily precipitation data from ERA5 reanalyses, 29 CMIP6 global climate models and 18 EURO-CORDEX regional climate models were employed to evaluate extreme precipitation through 10 indices, following the ETCCDI definitions. The analysis was performed over the entire GAR, with a specific focus on the Piedmont region for regional models, taking advantage of their higher spatial resolution.
Firstly, the capability of the models to represent precipitation and its extremes in the area was evaluated, particularly considering the effects of spatial resolution. Both the probability distribution of precipitation and its extremes, and the spatial distribution of the indices in the recent past were analysed. A clustering technique was adopted to group models based on the probability distributions of the indices, and a score indicating the similarity between the ERA5 and modeled spatial distribution computed. Eventually, a bias correction method was applied to specific CMIP6 models in order to evaluate a possible improvement in their performance.
Our results highlight a group of models that clearly clustered similarly to ERA5, showing the best scores for both the precipitation distributions and their spatial patterns. The cluster could be further enlarged by adopting the bias corrected models. Since such a cluster improved the model analysis as compared to the ensemble mean, the selected models were used to evaluate projections of precipitation extremes to the end of the century, with particular attention to their elevational dependency.

ID: 3.14046

Elevation dependent warming in Norway ?

Ketil Isaksen
Gjelten, Herdis Motrøen; Canclini, Alessio; Lussana, Cristian; Benestad, Rasmus E.; Båserud, Line; Dobler, Andreas; Erlandsen, Helene Birkelund; Hanssen-Bauer, Inger; Lutz, Julia; Nordli, Øyvind; Ødemark, Karianne; Etzelmüller, Bernd; Ødegård, Rune S.

Abstract/Description

The mountainous regions are perceived as significant climate “hotspots,” capable of intensifying climatic changes observed in other areas. The principle of elevation-dependent warming (EDW), which indicates that warming rates differ based on elevation, is widely recognized. Several studies show that temperature trends at mountain locations can be significantly different from those at nearby low-elevations. EDW may arise from various mechanisms, including changes in snow albedo and surface-based feedbacks, changes in water vapour–radiative feedbacks, changes in the cloud feedback and aerosol loading changes. Some factors will be more influential than others in certain parts of the world and at certain times of the year, and this may partly account for the differences in EDW. Investigations into EDW based on historical data are notably absent in high-latitude regions, including the Norwegian mountains. While extensive analyses have been conducted on comprehensive datasets primarily from lowland and coastal areas in Norway, the long-term temperature trends and variability within the mountainous regions of Norway have yet to be thoroughly examined, despite the country’s predominantly mountainous terrain. Meteorological observations in the Norwegian mountains were established in the early 20th century along the Bergen and Dovre railways, and two high mountain observatories were established in the 1930s. A number of new weather stations have been established in the mountains in Norway over the past 30 years. This research seeks to establish homogeneous temperature reference series for the mountainous regions of Norway, utilizing a unique dataset obtained from mountain weather stations. Furthermore, the study investigates long-term trends and variability in air temperature derived from both observational data and gridded datasets, particularly in relation to the lowland areas. In terms of future climate, some multi-model ensemble projections for the 21st century in northern Europe suggest that the strongest warming is estimated for high elevations in Scandinavia. On the other hand, other studies using statistical downscaling of temperature indicate increased warming at valley stations compared to neighbouring mountain stations, particularly in winter. We discuss potential processes that may be driving EDW in Norway and thus influence the future projections in different ways.

ID: 3.16735

Third Pole Archives: Dendroclimatic Potential of Unexplored High-Altitude Alpine Flora in a Changing Climate

Mohit Phulara
Dolezal, Jiri; Bhatt, Indra Dutt; Owczarek, Magdalena Opała; Owczarek, Piotr; Sekhar, Chandra

Abstract/Description

Recent climatic shifts are rapidly reshaping the environmental dynamics of polar and alpine regions, significantly impacting sensitive ecosystems in the Arctic and the Himalayas. These regions are experiencing unprecedented climatic fluctuations, challenging the resilience and adaptability of native flora. While dendroclimatological studies focusing on high-altitude trees in the Himalayas have been conducted extensively for decades, providing valuable insights into climate change impacts, their smaller counterparts—high-altitude shrubs—remain largely unexplored. Extensive research in the Arctic has demonstrated clear growth-ring formations in shrub species, revealing their sensitivity to environmental changes; however, similar research in the “Third Pole”—the high-altitude Himalayan zones—remains limited. This study extends dendroclimatic analyses to previously un-investigated shrub species found at elevations above 4000 m a.s.l. in the Indian Himalayas. Systematic sampling of approximately 150 plant specimens from five targeted shrub species, coupled with dendrochronological analyses, revealed distinct annual growth rings with clear boundaries, confirming their potential as reliable indicators of climatic variability. Preliminary results indicate that these shrub species accurately record annual climatic fluctuations, serving as valuable proxies for reconstructing past climate conditions and monitoring the recent impacts of global warming. Our initial findings underscore the significant yet untapped dendroclimatological potential of Himalayan high-altitude shrubs. Highlighting the ecological sensitivity and unique adaptive mechanisms of these species, this research advocates for further dendroclimatic studies and targeted conservation initiatives in the Himalayas, a critical biodiversity hotspot essential for understanding climate-driven ecological resilience and vulnerability.