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Everest’s thinning glaciers: implications for tourism and mountaineering

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Glacier mass loss in the Everest region of Nepal is accelerating in response to a warming climate, which is a trend observed across the central and eastern Himalaya. Thinning glaciers and the development of supraglacial (surface) ponds and large glacial lakes will increasingly restrict access to glacier surfaces and will affect popular trekking routes and mountaineering activities in the region. Through quantifying glacier accessibility and supraglacial pond expansion, we estimate that the Kongma La Pass trail across the Khumbu Glacier is likely to be impassable by 2020 due to supraglacial pond expansion and glacier thinning, and will require significant re-routing. An estimated 197 649 227 m³ of ice melted over the period 1984–2015 on the Khumbu Glacier. Additionally, expert opinion from Everest mountaineers suggest that rockfall activity is likely to increase in the high-mountain environment as snow and ice melts from mountain slopes, requiring changes to climbing routes on the world's highest peaks. Similarly, route difficulty will be affected by changing monsoon precipitation patterns, which determines windows of opportunity for ascents, and the distribution and quantity of snowfall. We conclude that increased collaboration between the scientific, local, and mountaineering communities offers mutual benefits for data collection and dissemination, and we identify key areas that should be investigated further.
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© John Wiley & Sons Ltd, The Geologists’ Association & The Geological Society of London,
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Feature
Everest’s thinning glaciers: implications for
tourism and mountaineering
C. Scott Watson1, 2,
& Owen King1
1School of Geography and
water@leeds, University of
Leeds, Leeds, UK
scott@rockyglaciers.co.uk
2Department of Hydrology
& Atmospheric Sciences,
University of Arizona,
Tucson, USA
Glacier mass loss in the Everest region of Nepal is accelerating in response to
a warming climate, which is a trend observed across the central and eastern
Himalaya. Thinning glaciers and the development of supraglacial (surface)
ponds and large glacial lakes will increasingly restrict access to glacier
surfaces and will affect popular trekking routes and mountaineering activities
in the region. Through quantifying glacier accessibility and supraglacial pond
expansion, we estimate that the Kongma La Pass trail across the Khumbu
Glacier is likely to be impassable by 2020 due to supraglacial pond expansion
and glacier thinning, and will require significant re-routing. An estimated
197 649 227 m3 of ice melted over the period 1984–2015 on the Khumbu
Glacier. Additionally, expert opinion from Everest mountaineers suggest
that rockfall activity is likely to increase in the high-mountain environment
as snow and ice melts from mountain slopes, requiring changes to climbing
routes on the world’s highest peaks. Similarly, route difficulty will be affected
by changing monsoon precipitation patterns, which determines windows
of opportunity for ascents, and the distribution and quantity of snowfall.
We conclude that increased collaboration between the scientific, local, and
mountaineering communities offers mutual benefits for data collection and
dissemination, and we identify key areas that should be investigated further.
Many Himalayan glaciers feature a mantle of debris
that can be several metres thick. This debris layer is
composed of clasts of various size, ranging from fine
silts to large boulders, which is predominantly sourced
from the surrounding mountains and transported
down-valley by glacier flow. The debris insulates the
ice beneath when exceeding a thickness of several
centimetres, but can also amplify ice melt if the debris
layer is very thin (< 3 cm), due to the preferential
absorption and transfer of solar radiation by the
much darker rock and sediment. The thickness of this
debris layer is spatially heterogeneous, which leads
to variable melt rates across the glacier surface and
the development of an uneven surface topography
(Fig. 1). Supraglacial ponds (Fig. 1a) and ice cliffs
(Fig. 1b) on the surface of glaciers are considered
‘hot-spots’ of melt, the magnitude of which is revealed
when using fine-resolution imagery and digital
elevation models (DEMs) of difference to quantify
surface elevation changes.
Ice cliffs retreat on the order of several to tens
of metres each year, depending upon the presence
of an adjacent supraglacial pond, which increases
melt through thermo-erosion at the cliff base.
Supraglacial ponds with adjacent ice cliffs are highly
turbid, which is caused by debris influx from cliff-
tops as they retreat. High pond turbidity increases the
absorption of solar radiation and this thermal energy
is transmitted to the underlying glacier ice, or inside
the glacier during drainage if the pond intercepts an
englacial conduit. Ponds therefore enhance glacier
melt and promote the formation of new ice cliffs and
pond basins as englacial conduits collapse to leave
depressions in the glacier surface, forming a positive
feedback that often leads to the development of large,
moraine-impounded lakes.
Large glacial lakes are a concern to downstream
communities and infrastructure including hydropower
This is an open access article
under the terms of the Creative
Commons Attribution License,
which permits use, distribution
and reproduction in any medium,
provided the original work is
properly cited.
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Geology Today
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facilities, since the lakes are dammed by moraines
composed of glacially derived debris of unknown
stability. Avalanches or rock falls into the lake, or
a destabilizing of the dam via an event such as an
earthquake, can initiate catastrophic drainage events
termed glacial lake outburst floods (GLOFs) where
large volumes of water flow rapidly downstream.
Additionally, the internal glacier hydrology can
become re-organized or blocked as the surface lowers
and sudden drainage can occur without warning,
causing smaller outburst flood events.
Recent studies have primarily focused on how the
disappearance of glaciers will affect the number and
size of glacial lakes, with associated GLOF hazards; and
a change in the magnitude and seasonality of river
flows, with associated implications for downstream
irrigation, sanitation and hydropower use. However,
the implications of glacier disappearance for tourism
and mountaineering activities remain unexplored,
despite their importance for socio-economic
development in glacierized regions (e.g. the Sagarmatha
and Annapurna National Parks in Nepal). Glacier
surfaces that are becoming increasingly disconnected
from the surrounding topography makes access ever
more difficult for trekking trails that use the glaciers
as shortcuts across valleys (e.g. Fig. 2). Additionally,
hazards threatening mountaineering activities, such
as avalanches and rockfalls, are likely to increase as
mountain slopes become snow and ice-free.
In this study, we explore the implications of
glacier thinning and climate change on trekking and
mountaineering activities in Sagarmatha National
Park in Nepal, which is visited by tens of thousands of
tourists each year. We present an analysis of glacier
surface lowering, glacier velocity, and supraglacial
pond expansion, to determine how glacier dynamics
and accessibility is changing over time. Additionally,
we relate the views of three expert mountaineers to
describe changing trends at high altitude, which is
generally not accessed or well documented by the
scientific community.
Tourism in Sagarmatha National Park
The tourist economy in Sagarmatha National Park
now eclipses traditional farming activities and has
brought employment opportunities, electricity and
internet access to remote mountain communities.
However, this also brings local environmental
pressures as tourist numbers increase, with higher
expectations regarding accommodation, washing-
facilities and reliable internet access.
Visitors to the national park include tourists
trekking along popular trails, often to visit Everest
Base Camp (EBC), and mountaineers accessing Mount
Everest and other high-altitude peaks. Trekking
trails often pass over glaciers including the routes
Fig. 1. Surface features on
the debris-covered Khumbu
Glacier including: a. supraglacial
ponds that can exceed tens of
metres in depth, b. the Kongma
La Pass trail passing between
two supraglacial ponds and
a retreating ice cliff, and c,d.
views of Everest Base Camp and
the transition from clean-ice to
debris-covered ice as the glacier
descends the Khumbu Icefall.
(a) (b)
(c) (d)
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of the Kongma La Pass and the Chola Pass trails,
which cross the Khumbu and Ngozumpa glaciers
respectively (Fig. 2). However, these routes are
frequently diverted in response to challenges posed
by the increasing elevation difference between the
Little Ice Age (LIA) glacial moraines (formed 400–
700 years ago) and the contemporary glacier surface
(Fig. 3a), and the expansion of supraglacial ponds.
The increasing prevalence of GPS-enabled watches
and smartphones with integrated barometers means
that trekking journeys are often recorded along with
time-stamps and altitude profiles, which are frequently
made available online (e.g. Fig. 2). These data offer
new opportunities for crowdsourcing data on popular
trekking trails, including how route selection changes
through time, and how the elevation of the glacier
surface is changing.
Glacier thinning
Surface lowering is perhaps the most pronounced
evidence of glaciers out of equilibrium with current
climatic conditions and is visible from the vertical
offset between the LIA moraines and the present-day
glacier surface (Fig. 3a). Glacier surface lowering can
be quantified by comparing multi-temporal DEMs
derived from satellite imagery. On heavily debris-
covered glaciers the maximum surface lowering
occurs mid-way up the glacier where the debris-
cover is thinner; however, localized hot-spots of melt
are visible around ice cliffs and supraglacial ponds.
Quantifying the magnitude of melt is important for
predicting the longevity of glaciers in the region, and
subsequent change in river runoff. Additionally, the
distribution of melt across a glacier surface reveals the
likelihood of glacial lake development, since meltwater
can effectively pond on low gradient glaciers, which
allows individual ponds to coalesce.
Using DEMs from 1984 and 2015 the surface
elevation change of the debris-covered Khumbu
Glacier was calculated and was used to estimate the
volume of ice lost. At Lobuche, the average surface
elevation change 1984–2015 was –15.8 m, or –0.51
m/yr (Fig. 3c). At EBC, where the glacier debris-cover
is thinner, this was –31.3 m, or –1.01 m/yr (Fig. 3d).
This lowering equates to a total ice volume loss of
–197 649 227 m3 across the debris-covered area
(Fig. 3b). Although Khumbu and other glaciers in the
region still act as reservoirs, storing a large amount
of water as glacial ice, it is clear that this resource is
rapidly depleting, which will affect the magnitude and
seasonality of river flows.
Several studies have predicted that a glacial lake
will develop on the Khumbu Glacier as mass loss
continues, which will itself change the glacier’s
dynamics. Imja Tsho is a well-known glacial lake,
which is expanding by 26 000 m2/yr. Here, lake
water acts to thermally erode the glacier terminus
and promote calving into the lake, causing rapid
lake expansion and glacial retreat. In addition to
Fig. 2. Debris-covered glaciers
around Mount Everest and
popular trekking trails. The
trekking heatmap is derived
from publically available Suunto
global positioning system (GPS)
watch data.
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Geology Today
, Vol. 34, No. 1, January–February 2018
acting as a positive-feedback mechanism promoting
glacier mass loss, glacial lakes require assessment and
monitoring strategies to address their outburst flood
risk, and in extreme cases, remediation to mitigate
against potential flooding.
Glacier velocity
Variations in glacier thickness and the surface gradient
of a glacier control the driving stress required for
glacier movement. Driving stress decreases as glaciers
thin, since melting ice in the ablation zone is not
replaced by sufficient ice flux generated from snowfall
in the accumulation zone. Therefore, glacier velocity
is expected to decrease in response to reduced snow
accumulation at high elevations and ongoing surface
lowering at lower elevations.
We used the feature tracking algorithm in COSI-
Corr (an add-on for the remote sensing package,
ENVI) to derive glacier velocities using two Planet
Labs satellite images acquired in 2016 and 2017.
The stagnant tongues of Khumbu and Ngozumpa
glaciers are visible in Fig. 4, where flow velocity
reduces from rates exceeding 50 m/yr to less than
10 m/yr several kilometres up-glacier from respective
termini. The englacial drainage system is subject to
less disturbance where glacier velocities are low,
hence supraglacial ponds are less likely to drain
into the glacier through fractures at the pond bed.
Therefore, as relic conduits collapse to produce new
surface depressions and the glacier becomes thinner,
the conditions become favourable for larger glacial
lakes to form near the glacier terminus as individual
ponds coalesce (e.g. Fig. 5).
Glacier accessibility
Glacier surface lowering and velocity influence the
accessibility of the surface, which is a function of
its topographic characteristics, including slope and
surface roughness; and surface features, including
supraglacial ponds, ice cliffs, debris-cover and
crevasses. Topographic characteristics can be
modelled using a DEM and geographical information
system software to characterize the difficulty or
‘cost’ encountered by a person crossing the glacier
surface (Fig. 5). Here terrain difficulty was calculated
using surface slope averaged over a 10 × 10 m
moving window, and surface roughness, which we
approximate using the standard deviation of elevation
over a 10 × 10 m moving window. Impassable features
were incorporated into the terrain difficulty layer
and included supraglacial ponds, and slopes with
angles greater than 35°. Least-cost paths were then
Fig. 3. a. The lower
debris-covered tongue of
Khumbu Glacier showing the
contemporary glacier surface
in relation to the Little Ice Age
moraines. b. Surface elevation
change on Khumbu Glacier
1984−2015 with a hillshaded
DEM backdrop. Inset locations
are: c. Lobuche and d. Everest
Base Camp.
(a) (b)
(c) (d)
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calculated across the glacier at the location of the
Kongma La Pass trail using 50 randomly generated
start and end locations (Fig. 5).
Accessibility across the Khumbu Glacier decreased
from 1984 to 2015, shown by the reduction from five
main paths crossing the glacier to three respectively.
This is largely due to the expansion of supraglacial
ponds, which increased in area from 28 755 m2
to 139 015 m2 (383%) from 1984 to 2015 in the
location shown (Fig. 5). The three remaining crossing
points exploit the last remaining land bridges between
the connected chains of ponds. Without these land
bridges the Kongma La Pass trail would require a
detour around the front of the glacier and based
on pond expansion rates from 2011 to 2015, these
land bridges are likely to disappear by 2020. The
cost of crossing the glacier surface is also affected
by the surface lowering such that accessing the
glacier surface requires a greater and in some cases
steeper descent, followed by a greater ascent off the
glacier. The average cost of crossing Khumbu Glacier
considering all routes increased by 19% from 1984
to 2015 (Fig. 5). Notably, the trail changed in 2017
due to the loss of one land bridge, and the opening of
a new crossing point due to the partial drainage of a
supraglacial pond.
We also performed the least-cost path analysis on
Ngozumpa Glacier at the location of the Chola Pass
trail. There are no clear pinch-points where the route
is likely to become blocked within the next five years
and although the route will likely change in response
to supraglacial pond expansion and ice cliff retreat,
there are still many opportunities for small diversions.
However, up-glacier expansion of Spillway Lake on
the terminus of the glacier may ultimately prevent
across-glacier access since estimates suggest it could
become several kilometres long.
Collaborative science in the high-mountain
environment
Environmental scientists have access to a range
of datasets, which can be used to monitor
glacier surface elevation change, glacier velocity,
supraglacial pond dynamics and land cover change.
However, field campaigns are generally restricted to
elevations < 6000 m, which means there are limited
measurements of high-altitude glacier characteristics
and snow accumulation. Precipitation rates are
essential inputs to models of future glacier mass
balance and could be better understood through
the collection of snow cores in glacier accumulation
zones. Sherpas and mountaineers who routinely
access the high-mountain environment have an
understanding of local environmental changes and
have the logistical infrastructure that could be used
Fig. 5. A least-cost path (LCP)
assessment of accessibility
across the Khumbu Glacier using
DEMs from 1984 and 2015.
Hillshaded DEMs are used as
the backdrop. A high number
of least cost paths indicates
an easier crossing route. The
LCPs are derived by considering
terrain difficulty and the
presence of barrier features such
as ice cliffs, supraglacial ponds
and steep slopes.
Fig. 4. Glacier velocities
(2016−2017) derived from
feature tracking on PlanetScope
satellite imagery.
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, Vol. 34, No. 1, January–February 2018
to transport scientific equipment and samples. The
expert views of local and international mountaineers
are therefore valuable to the scientific community,
and collaborations could have mutual benefits for
monitoring and forecasting changes in the high-
mountain environment (Table 1).
We sought the views of three Mount Everest
mountaineers regarding environmental change, and
opportunities for scientific collaboration, which are
summarized in Fig. 6. Several key themes emerged
including an increased frequency of rockfall events
requiring climbing route changes, and reduced
snowfall and changing weather patterns creating
harder climbing conditions. Warming temperatures
are known to affect the stability of mountain rock
slopes, such that the loss of snow cover and glacial
debuttressing are likely accompanied by an increase
in rockfall activity. Additionally, temporal changes
in the summer monsoon and declining precipitation
trends are observed around Everest, which were also
identified by the mountaineers. It was suggested that
climbing conditions would become more difficult if
these trends continue and there would be a shift in
preferable locations and routes for mountaineering
activities.
Opportunities for collaborations included
the communication of important trends to the
Table 1. Collaborative opportunities to improve climate change adaptation in the high-mountain environment
Knowledge base and collaborative opportunities Benefits
Local communities
Observations of environmental change e.g. snow cover,
precipitation seasonality, growing season, flood events
Used to complement remote sensing change detection and
forecast future change
Participatory science e.g. collecting repeat photographs and
water samples
Documentation of landscape change. Measuring river flow
contributions from glacier melt, snow melt, and rainfall, which
can be used to guide water use and storage strategies
Links with mountaineering Sherpas and village development
committees
Dissemination and discussion of scientific findings and
adaptation strategies
Local and international
mountaineers
Regular visits to the high-mountain environment over decadal
timescales
Multi-temporal photograph archives documenting snow/ice
cover change
Specialist knowledge of the high-mountain environment
Logistical support and permits. Mountaineers becoming
partners on scientific grants
Access to high altitude peaks where scientific equipment could
be transported and snow samples retrieved. Public exposure of
scientific activities and mountaineering partners
GPS track-logs Documentation of route choice. Multi-temporal measurements
of route elevation.
Scientific community
Interpretation of satellite imagery archives and access to fine-
resolution imagery and digital elevation models
Mountaineering route selection and hazard identification
Flood modelling to identify glacial lake outburst flood risk
Long-term temperature, precipitation and river flow data Forecasting hydrological change due to climatic warming
mountaineering community in an easily accessible
form (e.g. dated maps), and collaborative expeditions
where scientists or scientific equipment could
‘piggyback’ on mountaineering expeditions. In lower
altitude mountainous regions (e.g. the European
Alps), there is less distinction between scientific
and mountaineering communities and indeed many
glaciologists would also identify as mountaineers.
However, in the high-altitude Himalaya, expeditions
typically require more extensive logistical and technical
support and the acquisition of mountaineering
permits, which restricts scientific access. Cooperation
with local and international expeditions could
therefore be highly beneficial to both parties, since
the derived scientific work would be directly relevant
to supporting expeditions.
Summary
Himalayan glacier mass loss will continue in
response to climatic warming, which will influence
river flows, the development of glacial lakes, and
access to the high-mountain environment. Reduced
glacier and mountain accessibility has implications
for mountaineers and trekking tourists, which now
support entire communities in popular trekking areas.
We have presented a case-study from the Sagarmatha
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Geology Today
, Vol. 34, No. 1, January–February 2018
National Park in Nepal where glacier mass loss is
affecting trekking and mountaineering activities
around the world’s highest peak. We revealed that
ongoing expansion of supraglacial ponds on the
Khumbu Glacier is likely to block the Kongma La Pass
trail by 2020, which will require diversion around the
glacier terminus. In contrast, the Chola Pass trail on
Ngozumpa Glacier has alternative pathways available
to avoid expanding ponds and ice cliffs, although
this may change in coming decades if Spillway Lake
continues to expand up-glacier.
Additionally, expert opinion from Everest
mountaineers suggest that rockfall events and
changing weather patterns will increasingly affect
mountaineering activities as the climate warms and
snowfall decreases in the region. We propose that
collaboration between scientists and mountaineering
expeditions offer a valuable opportunity for data
collection, and direct feedback of these results could
be used to inform expedition planning.
Acknowledgements
We thank Jake Norton (MountainWorld Productions)
and two anonymous mountaineers who offered
their expertise to help develop this study. C.S.W
acknowledges support: the Mount Everest Foundation,
the British Society for Geomorphology, the Royal
Geographical Society (with IBG), the Petzl Foundation,
and water@leeds. O.K. is a recipient of a NERC DTP
PhD studentship. The Natural Environment Research
Council Geophysical Equipment Facility is thanked for
loaning Global Navigation Satellite Systems receivers
and technical assistance under loan numbers 1050,
1058 and 1065. Dhananjay Regmi and Himalayan
Research Expeditions are thanked for fieldwork
support including research permit acquisition, and
Mahesh Magar is thanked for invaluable support
during data collection. Duncan Quincey is thanked
for providing comments on this study and Evan Miles
for providing details of changes to the Kongma La
Pass trail in 2017.
Suggestions for further reading
Bolch, T., Pieczonka, T. & Benn, D.I. 2011. Multi-
decadal mass loss of glaciers in the Everest area
(Nepal Himalaya) derived from stereo imagery. The
Cryosphere, v.5, pp.349–358.
Carrivick, J.L. & Tweed, F.S. 2016. A global assessment
of the societal impacts of glacier outburst floods.
Global and Planetary Change, v.144, pp.1–16.
Garrard, R., Kohler, T., Price, M.F., Byers, A.C.,
Sherpa, A.R. & Maharjan, G.R. 2016. Land use
and land cover change in Sagarmatha National
Park, a World Heritage Site in the Himalayas of
eastern Nepal. Mountain Research and Development,
v.36, pp.299 310.
King, O., Quincey, D.J., Carrivick, J.L. & Rowan, A.V.
2017. Spatial variability in mass loss of glaciers
in the Everest region, central Himalayas, between
2000 and 2015. The Cryosphere. v.11, pp.407–
426.
Leprince, S., Barbot, S., Ayoub, F. & Avouac, J.P.
2007. Automatic and precise orthorectification,
coregistration, and subpixel correlation of satellite
images, application to ground deformation
measurements. IEEE Transactions on Geoscience and
Remote Sensing, v.45, pp.1529–1558.
McColl, S.T. 2012. Paraglacial rock-slope stability.
Geomorphology, v.153–154, pp.1–16.
Miles, E.S., Pellicciotti, F., Willis, I.C., Steiner, J.F., Buri,
Fig. 6. A summary of
mountaineering hazards
and opportunities in the
Everest region identified
by mountaineers. Bold text
indicates themes identified by
several mountaineers.
25
FEATURE
© John Wiley & Sons Ltd, The Geologists’ Association & The Geological Society of London,
Geology Today
, Vol. 34, No. 1, January–February 2018
P. & Arnold, N.S. 2016. Refined energy-balance
modelling of a supraglacial pond, Langtang Khola,
Nepal. Annals of Glaciology, v.57, pp.29–40.
Nuimura, T., Fujita, K., Yamaguchi, S. & Sharma,
R.R. 2012. Elevation changes of glaciers revealed
by multitemporal digital elevation models
calibrated by GPS survey in the Khumbu region,
Nepal Himalaya, 1992-2008. Journal of Glaciology,
v.58, pp.648–656.
Planet Team. 2017. Planet application program
interface. In: Space for Life on Earth. San Francisco,
CA. https://api.planet.com.
Quincey, D.J., Luckman, A. & Benn, D. 2009.
Quantification of Everest region glacier velocities
between 1992 and 2002, using satellite radar
interferometry and feature tracking. Journal of
Glaciology, v.55, pp.596–606.
Rounce, D.R., Byers, A.C., Byers, E.A. & McKinney,
D.C. 2017. Brief communication: observations of a
glacier outburst flood from Lhotse Glacier, Everest
area, Nepal. The Cryosphere, v.11, pp.443–449.
Rounce, D.R., McKinney, D.C., Lala, J.M., Byers, A.C.
& Watson, C.S. 2016. A new remote hazard and
risk assessment framework for glacial lakes in
the Nepal Himalaya. Hydrology and Earth System
Sciences, v.20, pp.3455–3475.
Rowan, A.V., Egholm, D.L., Quincey, D.J. & Glasser,
N.F. 2015. Modelling the feedbacks between mass
balance, ice flow and debris transport to predict
the response to climate change of debris-covered
glaciers in the Himalaya. Earth and Planetary
Science Letters, v.430, pp.427–438.
Sakai, A., Takeuchi, N., Fujita, K. & Nakawo, M.
2000. Role of supraglacial ponds in the ablation
process of a debris-covered glacier in the Nepal
Himalayas. In: Nakawo, M., Raymond, C.F. &
Fountain, A., eds. IAHS Publ. 264 (Symposium at
Seattle 2000—Debris-Covered Glaciers), Seattle, WA,
USA. IAHS Publishing, pp.119–130.
Salerno, F., Guyennon, N., Thakuri, S., Viviano, G.,
Romano, E., Vuillermoz, E. Cristofanelli, P., Stocchi,
P., Agrillo, G., Ma, Y. & Tartari, G. 2015. Weak
precipitation, warm winters and springs impact
glaciers of south slopes of Mt Everest (central
Himalaya) in the last 2 decades (1994–2013). The
Cryosphere, v.9, pp.1229–1247.
Shea, J.M., Immerzeel, W.W., Wagnon, P., Vincent,
C. & Bajracharya, S. 2015. Modelling glacier
change in the Everest region, Nepal Himalaya. The
Cryosphere, v.9, pp.1105–1128.
Thakuri, S., Salerno, F., Bolch, T., Guyennon, N.
& Tartari, G. 2016. Factors controlling the
accelerated expansion of Imja Lake, Mount Everest
region, Nepal. Annals of Glaciology, v.57, pp.245–
257.
Thompson, S., Benn, D., Mertes, J. & Luckman, A.
2016. Stagnation and mass loss on a Himalayan
debris-covered glacier: processes, patterns and
rates. Journal of Glaciology, v.62, pp.467–485.
Watson, C.S., Quincey, D.J., Carrivick, J.L. & Smith,
M.W. 2016. The dynamics of supraglacial ponds
in the Everest region, central Himalaya. Global and
Planetary Change, v.142, pp.14–27.
Watson, C.S., Quincey, D.J., Carrivick, J.L. & Smith,
M.W. 2017. Ice cliff dynamics in the Everest
region of the Central Himalaya. Geomorphology,
v.278, pp.238–251.
... D'autres études se sont concentrées sur l'impact du changement climatique sur les activités estivales en haute montagne. Parmi elles, on peut noter quelques travaux menés sur les guides de hautes montagnes (Salim et al., 2019 ;Mourey et al., 2020), sur la pratique des treks de haute altitude (Purdie & Kerr, 2018;Watson & King, 2018), sur les accès aux refuges de haute montagne (Mourey & Ravanel, 2017 ;Mourey et al., 2019b) ou encore sur l'évolution des itinéraires d'alpinisme et sur la dangerosité de certains d'entre eux (Mourey et al., 2019a ;Mourey et al., 2021). Parmi ces recherches, le tourisme glaciaire -ensemble des pratiques et activités touristiques et récréatives ayant lieu sur ou autour d'un glacier et dont celui-ci constitue l'une des 4 principales ressources marketing -occupe une place relativement restreinte malgré son importance historique. ...
... À travers le monde, les stratégies d'adaptation mises en place comprennent sept catégories : les changements d'accès, la substitution spatiale, la substitution temporelle, l'éducation à l'environnement, les changements d'activités, la planification touristique et l'atténuation du retrait glaciaire.Les changements d'accès comprennent la création d'itinéraires pour des activités nouvelles comme pour la randonnée au Jökulsárlón, en Islande. Ces nouveaux itinéraires peuvent également être construits ou équipés pour maintenir les activités existantes, par exemple l'accès aux refuges des Alpes occidentales(Mourey et al., 2019b), au camp de base de l'Everest(Watson & King, 2018) ou à des glaciers islandais(Welling & Abegg, Cette substitution spatiale s'accompagne d'une substitution temporelle, avec un changement de saisonnalité chez les guides de haute montagne français. Les bonnes conditions en haute montagne se réduisant en juillet-août, ils augmentent leur temps de travail au printemps et, plus marginalement, à l'automne ...
... Chacaltaya est un sommet de plus de 5 400 m facilement accessible, avec un panorama et de la neige en hiver appréciés des Brésiliens, les acteurs proposent de développer un centre d'entraînement pour les athlètes ou un musée des glaciers ; ils pensent que le site pourrait attirer des touristes pour voir un endroit où l'effondrement s'est produit(Kaenzig et al., 2016).Les lacs proglaciaires récemment formés dans les Alpes européennes(Cathala et al., 2021) peuvent devenir une opportunité, car ce sont de bons attracteurs touristiques ; ils peuvent également constituer de nouvelles opportunités pour l'hydroélectricité. Mais ils peuvent aussi devenir une nouvelle menace, notamment parce que des écroulements rocheux liés au réchauffement du permafrost peuvent y déclencher des vagues destructrices(Haeberli et al., 2016) ; ils peuvent aussi augmenter les difficultés pour atteindre le glacier, comme sur la principale voie d'ascension du Mont Everest(Watson et King, 2018).Figure 29. Spatialisation des articles et des différents impacts observés du changement climatique sur le tourisme glaciaire(Salim et al., 2021c).L'analyse de la littérature (Figure 29) montre que le tourisme glaciaire au niveau mondial est impacté par divers processus liés au changement climatique, glaciaires, périglaciaires et ...
Thesis
After being perceived negatively by the inhabitants of mountain areas, glaciers have been promoted as a tourist attraction for over two centuries. The first visits to the Arveyron Arch (Chamonix) in the 18th century were followed by cog railways and cable cars that allow access to the largest glaciers in the Alps and in the world in just a few dozen minutes. Thus, glacier tourism today includes practices and touristic sites that are emblematic of certain mountain territories. However, rising temperatures and the extremely rapid glacier retreat also make these glacier sites markers of climate change. The Mer de Glace in France, the Rhone glacier in Switzerland and the Pasterze glacier in Austria are among the major glacier tourist sites that are experiencing the full force of landscape changes linked to the retreat of the cryosphere. What do these changes imply for the operators of these glacier tourism sites? And for their visitors? Using mixed methodologies, this PhD thesis attempts to answer these two questions for six major Alpine glacier tourism sites. In essence, the results show that glacial tourism sites are largely impacted by climate change and the glaciological and geomorphological changes it brings to mountain territories. These impacts lead to difficulties in site management, itinerary issues, difficulties in carrying out certain activities which may become more dangerous, or a decrease in the attractiveness of the sites through less attractive glacial activities or through a "landscape degradation" feared by the site managers. However, our results with visitors to the sites show that this "degradation" of the landscape does not drastically reduce visitors' satisfaction with the glacial landscape: the negative judgements are limited to glaciers or paraglacial forms, but only slightly affect visitors' general appreciation of the landscape. At the same time, a new form of tourism - last chance tourism - is developing around glaciers and shows that they are now considered as "endangered species". Furthermore, the site managers in question are implementing strategies for adapting to climate change that are mainly reactive and which raise the question of their long-term sustainability. This question is even more important as glacier modelling for the year 2050 suggests that current adaptations will not be sufficient.
... D'autres études se sont concentrées sur l'impact du changement climatique sur les activités estivales en haute montagne. Parmi elles, on peut noter quelques travaux menés sur les guides de hautes montagnes (Salim et al., 2019 ;Mourey et al., 2020), sur la pratique des treks de haute altitude (Purdie & Kerr, 2018;Watson & King, 2018), sur les accès aux refuges de haute montagne (Mourey & Ravanel, 2017 ;Mourey et al., 2019b) ou encore sur l'évolution des itinéraires d'alpinisme et sur la dangerosité de certains d'entre eux (Mourey et al., 2019a ;Mourey et al., 2021). Parmi ces recherches, le tourisme glaciaire -ensemble des pratiques et activités touristiques et récréatives ayant lieu sur ou autour d'un glacier et dont celui-ci constitue l'une des principales ressources marketing -occupe une place relativement restreinte malgré son importance historique. ...
... À travers le monde, les stratégies d'adaptation mises en place comprennent sept catégories : les changements d'accès, la substitution spatiale, la substitution temporelle, l'éducation à l'environnement, les changements d'activités, la planification touristique et l'atténuation du retrait glaciaire.Les changements d'accès comprennent la création d'itinéraires pour des activités nouvelles comme pour la randonnée au Jökulsárlón, en Islande. Ces nouveaux itinéraires peuvent également être construits ou équipés pour maintenir les activités existantes, par exemple l'accès aux refuges des Alpes occidentales(Mourey et al., 2019b), au camp de base de l'Everest(Watson & King, 2018) ou à des glaciers islandais(Welling & Abegg, Cette substitution spatiale s'accompagne d'une substitution temporelle, avec un changement de saisonnalité chez les guides de haute montagne français. Les bonnes conditions en haute montagne se réduisant en juillet-août, ils augmentent leur temps de travail au printemps et, plus marginalement, à l'automne ...
... La dernière catégorie de stratégie d'adaptation est la planification touristique. Il s'agit de développer les collaborations entre les acteurs publics et privés des territoires(Watson & King, 2018;Welling & Abegg, 2019). Cette mise en réseau des acteurs favorise les lois de protection de l'environnement(Rasul et al., 2019;Wang et al., 2010; et les actions de recherche (Wang et al., 2010; Welling & Abegg, 2019). ...
Thesis
Après avoir été perçus négativement par les habitants des territoires de montagne, les glaciers ont, depuis plus de deux siècles, été l’objet d’une mise en tourisme. Aux premières visites de l’Arche de l’Arveyron (Chamonix) au XVIIIe siècle ont succédé trains à crémaillères et téléphériques permettant d’accéder et de contempler, en seulement quelques dizaines de minutes, les plus grands glaciers des Alpes et du monde. Ainsi, le tourisme glaciaire regroupe aujourd’hui des pratiques et des sites touristiques emblématiques de certains territoires de montagne. Cependant, l’augmentation des températures et le retrait extrêmement rapide des glaciers font également de ces sites glaciaires des marqueurs du changement climatique. La Mer de Glace en France, le glacier du Rhône en Suisse ou encore celui du Pasterze en Autriche, font parties de ces grands sites touristiques glaciaires qui subissent de plein fouet les changements paysagers liés au retrait de la cryosphère. Qu’est-ce que ces changements impliquent pour les acteurs de ces sites touristiques glaciaires ? pour leurs visiteurs ? À travers des méthodologies mixtes, cette thèse de doctorat tente d’apporter une réponse à ces deux questions pour six grands sites touristiques glaciaires alpins. En substance, les résultats montrent que les sites touristiques glaciaires sont largement impactés par le changement climatique et les modifications glaciologiques et géomorphologiques qu’il engendre pour les territoires de montagne. Ces impacts entrainent des difficultés de gestion des sites, des problématiques d’itinéraires, des difficultés à réaliser certaines activités et qui peuvent devenir plus dangereuses ou encore une baisse d’attractivité des sites par des activités glaciaires moins attrayantes ou par une « dégradation du paysage » redoutée par les gestionnaires des sites. Nos résultats auprès des visiteurs des sites montrent cependant que cette « dégradation » paysagère n’induit pas une baisse drastique de la satisfaction des visiteurs à l’égard du paysage glaciaire : les jugements négatifs se cantonnent aux glaciers ou aux formes paraglaciaires mais ne ternissent que très peu l’appréciation générale des visiteurs vis-à-vis du paysage. Dans le même temps, une nouvelle forme de tourisme – le tourisme de la dernière chance – se développe autour des glaciers et montre que ceux-ci sont aujourd’hui considérés comme des « espèces en voie de disparition ». Par ailleurs, les gestionnaires de sites en question mettent en place des stratégies d’adaptation au changement climatique qui sont principalement réactives et qui pose la question de leur soutenabilité long termes. Question d’autant plus importante que les modélisations glaciaires à l’horizon 2050 laissent penser que les adaptations actuelles ne seront pas suffisantes.
... Climate change also threatens mountaineering routes and hut access in the French Mont Blanc massif (Mourey & Ravanel, 2017;Mourey et al., 2019aMourey et al., , 2019b). Climate change has reduced the aesthetic value of the Forni glacier in Italy (Garavaglia et al., 2012), modified access to the normal Everest route (Watson & King, 2018), and led to the vanishing of touristic glaciers, such as the Chacaltaya glacier in Bolivia (Kaenzig et al., 2016). ...
... Iceland (Furunes & Mykletun, 2012;Welling & Abegg, 2019), the quality and sometimes feasibility of glacier activities have been reduced. Safety issues are comparable to those in New Zealand and Nepal (Purdie et al., 2015;Watson & King, 2018). Such infrastructure issues occur in Iceland (Welling & Abegg, 2019), and these management issues occur in New Zealand . ...
Article
Full-text available
Climate change strongly affects mountain tourism activities. Glacier tourism is highly affected by the retreat of glaciers. However, research on the effects and adaptations of glacier tourism to climate change is scarce in Europe. By analysing the glacio-geomorphological literature, semi-structured interviews, and observations at six major Alpine glacier tourism sites, we aim to identify the physical processes that affect glacier tourism in the Alps and how stakeholders perceive and adapt to them. The results reveal that glacier retreat and the associated paraglacial dynamics and permafrost warming strongly affect glacier tourism. Stakeholders perceive six main issues: management, itinerary, infrastructure, attractiveness, safety, and activity. In response, they have been adapting with eight strategies: management change, technical means implementation, mitigation, diversification, access and itinerary maintenance, heritage development, planning, and implementation of transformation projects. These strategies are discussed regarding their relevance to tourism model transition to guarantee future sustainability. Supplementary information: The online version contains supplementary material available at 10.1007/s10113-021-01849-0.
... Climate change also threatens mountaineering routes and hut access in the French Mont Blanc massif (Mourey & Ravanel, 2017;Mourey et al., 2019aMourey et al., , 2019b). Climate change has reduced the aesthetic value of the Forni glacier in Italy (Garavaglia et al., 2012), modified access to the normal Everest route (Watson & King, 2018), and led to the vanishing of touristic glaciers, such as the Chacaltaya glacier in Bolivia (Kaenzig et al., 2016). ...
... Iceland (Furunes & Mykletun, 2012;Welling & Abegg, 2019), the quality and sometimes feasibility of glacier activities have been reduced. Safety issues are comparable to those in New Zealand and Nepal (Purdie et al., 2015;Watson & King, 2018). Such infrastructure issues occur in Iceland (Welling & Abegg, 2019), and these management issues occur in New Zealand . ...
Preprint
Full-text available
Climate change strongly affects mountain tourism activities. Glacier tourism is highly affected by the retreat of glaciers. However, research on the effects and adaptations of glacier tourism to climate change is scarce in Europe. By analysing the glacio-geomorphological literature, semi-structured interviews, and observations at six major Alpine glacier tourism sites, we aim to identify the physical processes that affect glacier tourism in the Alps and how stakeholders perceive and adapt to them. The results reveal that glacier retreat and the associated paraglacial dynamics and permafrost warming strongly affect glacier tourism. Stakeholders perceive six main issues: management, itinerary, infrastructure, attractiveness, safety, and activity. In response, they have been adapting with eight strategies: management change, technical means implementation, mitigation, diversification, access and itinerary maintenance, heritage development, planning, and implementation of transformation projects. These strategies are discussed regarding their relevance to tourism model transition to guarantee future sustainability.
... Velocities calculated from surface displacements obtained by feature tracking indicate that ice flow through Khumbu Glacier declines rapidly below the upper ablation area where the glacier surface becomes debris covered (Quincey et al., 2009;Rowan et al., 2015). Velocities in the icefall (10.8-11.5 km upglacier from the terminal moraine) reached a maximum of about 100 m a −1 between 2016 and 2017 (Watson & King, 2018) and over one meter per day in May 2018 (Altena & Kääb, 2020). Velocities for the ablation area generated using auto-RIFT provided by the NASA MEaSUREs ITS_LIVE project indicate ice flow of 30-50 m a −1 in the upper ablation area (6.0-10.8 ...
Article
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Sustained mass loss from Himalayan glaciers is causing supraglacial debris to expand and thicken, with the expectation that thicker debris will suppress ablation and extend glacier longevity. However, debris-covered glaciers are losing mass at similar rates to clean-ice glaciers in High Mountain Asia. This rapid mass loss is attributed to the combined effects of; (a) low or reversed mass balance gradients across debris-covered glacier tongues, (b) differential ablation processes that locally enhance ablation within the debris-covered section of the glacier, for example, at ice cliffs and supraglacial ponds, and (c) a decrease in ice flux from the accumulation area in response to climatic warming. Adding meter-scale spatial variations in supraglacial debris thickness to an ice-flow model of Khumbu Glacier, Nepal, increased mass loss by 47% relative to simulations assuming a continuous debris layer over a 31-year period (1984–2015 CE) but overestimated the reduction in ice flux. Therefore, we investigated if simulating the effects of dynamic detachment of the upper active glacier from the debris-covered tongue would give a better representation of glacier behavior, as suggested by observations of change in glacier dynamics and structure indicating that this process occurred during the last 100 years. Observed glacier change was reproduced more reliably in simulations of the active, rather than entire, glacier extent, indicating that Khumbu Glacier has passed a dynamic tipping point by dynamically detaching from the heavily debris-covered tongue that contains 20% of the former ice volume.
... Those impacts had already been suggested by Welling et al. (2015) and our literature review confirms that glacier tourism all over the world is impacted by geomorphic processes driven by climate change (Figure 4). For instance, moraine destabilisation and glacier shrinkage make glacier access difficult (Mourey & Ravanel, 2017;Mourey et al., 2019;Stewart et al., 2016;Watson & King, 2018). ...
Article
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Globally, tourism is being deeply impacted by glacial retreat caused by climate change. However, research on stakeholders' adaptation to climatic change and its threat to the industry on tourism niche is currently inadequate. Thus, through a literature review of 61 glacier peer-reviewed papers, this paper highlights the advancement in research on glacier tourism and provides some basis for understanding stakeholders' adaptation strategies to climate change. The review shows that glacier tourism research publications increased between 2015 and 2020. It also identifies some impacts of climate change on the glacier tourism industry as well as 27 adaptation strategies to climatic change, which are classified under seven main themes: changes to access, activities, tourism planning, educational activities, temporal substitutions, spatial substitutions, and glacier shrinkage attenuation. We discuss the relevance of the resilience concept in the tourism industry and recommend that tourists' experiences should be enhanced by applying the findings of research on tourists' motivations and landscape perception and developing more adaptation-oriented research. The findings suggest that the glacier tourism industry can reduce its vulnerability to climate change through increased collaboration between tourism operators and climate and tourism researchers.
... The opening of a trekking route promoting this opportunity created tensions between a National Park and a local indigenous community in the Peruvian Andes over the management and allocation of revenue from the route (Rasmussen, 2019). The consequences of ongoing and future glacier retreat are projected to negatively impact trekking and mountaineering in the Himalaya (Watson and King, 2018). Reduced snow cover has also negatively impacted trekking in the Himalaya, since tourists find the mountains , and the relative proportion of these classified as either 'formal', 'autonomous' or 'undefined' (right pie chart). ...
Chapter
The cryosphere (including, snow, glaciers, permafrost, lake and river ice) is an integral element of high mountain regions, which are home to roughly 10% of the global population. Widespread cryosphere changes affect physical, biological and human systems in the mountains and surrounding lowlands, with impacts evident even in the ocean. Building on the IPCC’s 5th Assessment Report (AR5), this chapter assesses new evidence on observed recent and projected changes in the mountain cryosphere as well as associated impacts, risks and adaptation measures related to natural and human systems. Impacts in response to climate changes independently of changes in the cryosphere are not assessed in this chapter. Polar mountains are included in Chapter 3, except those in Alaska and adjacent Yukon, Iceland and Scandinavia, which are included in this chapter.
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Glacial lake outburst floods (GLOFs) pose a significant threat to downstream communities and infrastructure due to their potential to rapidly unleash stored lake water. The most common triggers of these GLOFs are mass movement entering the lake and/or the self-destruction of the terminal moraine due to hydrostatic pressures or a buried ice core. This study initially uses previous qualitative and quantitative assessments to understand the hazards associated with eight glacial lakes in the Nepal Himalaya that are widely considered to be highly dangerous. The previous assessments yield conflicting classifications with respect to each glacial lake, which spurred the development of a new holistic, reproducible, and objective approach based solely on remotely sensed data. This remote hazard assessment analyzes mass movement entering the lake, the stability of the moraine, and lake growth in conjunction with a geometric GLOF to determine the downstream impacts such that the present and future risk associated with each glacial lake may be quantified. The new approach is developed within a hazard, risk, and management action framework with the aim that this remote assessment may guide future field campaigns, modeling efforts, and ultimately risk-mitigation strategies. The remote assessment was found to provide valuable information regarding the hazards faced by each glacial lake and results were discussed within the context of the current state of knowledge to help guide future efforts.
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The ablation areas of debris-covered glaciers typically consist of a complex mosaic of surface features with contrasting processes and rates of mass loss. This greatly complicates glacier response to climate change, and increases the uncertainty of predictive models. In this paper we present a series of high-resolution DEMs and repeat lake bathymetric surveys on Ngozumpa Glacier, Nepal, to study processes and patterns of mass loss on a Himalayan debris-covered glacier in unprecedented detail. Most mass loss occurs by melt below supraglacial debris, and melt and calving of ice cliffs (backwasting). Although ice cliffs cover only ~5% of the area of the lower tongue, they account for 40% of the ablation. The surface debris layer is subject to frequent re-distribution by slope processes, resulting in large spatial and temporal differences in debris-layer thickness, enhancing or inhibiting local ablation rates and encouraging continuous topographic inversion. A moraine-dammed lake on the lower glacier tongue (Spillway Lake) underwent a period of rapid expansion from 2001 to 2009, but later experienced a reduction of area and volume as a result of lake level lowering and sediment redistribution. Rapid lake growth will likely resume in the near future, and may eventually become up to 7 km long.
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