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Glacial extent and mass balance are sensitive climate proxies providing solid information on past climatic conditions. However, series of annual mass-balance measurements of more than 60 years are scarce. To our knowledge, this is the first time the latewood density data (MXD) of the Swiss stone pine (Pinus cembra L.) have been used to reconstruct the summer mass balance (Bs) of an Alpine glacier. The MXD-based Bs well correlates with a Bs reconstruction based on the May to September temperature. Winter precipitation has been used as an independent proxy to infer the winter mass balance and to obtain an annual mass-balance (Bn) estimate dating back to the glaciological year 1811/12. The reconstructed MXD/precipitation-based Bn well correlates with the data both of the Careser and of other Alpine glaciers measured by the glaciological method. A number of critical issues should be considered in both proxies, including non-linear response of glacial mass balance to temperature, bedrock topography, ice thinning and fragmentation, MXD acquisition and standardization methods, and finally the ‘divergence problem’ responsible for the recently reduced sensitivity of the dendrochronological data. Nevertheless, our results highlight the possibility of performing MXD-based dendroglaciological reconstructions using this stable and reliable proxy.

Publisher's version (útgefin grein), In this paper, we give an overview of changes in area, length, surface elevation and mass balance of glaciers in mainland Norway since the 1960s. Frontal advances have been recorded in all regions except the northernmost glaciers in Troms and Finnmark (Storsteinsfjellbreen, Lyngen and Langfjordjokelen). More than half of the observed glaciers, 27 of 49, had marked advances in the 1990s. The glaciological mass-balance values for the period 1962-2018, where 43 glaciers have been measured, show great inter-annual variability. The results reveal accelerated deficit since 2000, the most negative decade being 2001-2010. Some years with a positive mass balance (or less negative) after 2010s can be attributed to variations in large-scale atmospheric circulation. A surface elevation change and geodetic mass balance were calculated for a sample of 131 glaciers covering 817 km in the '1960s' and 734 km in the '2010s', giving an area reduction of 84 km, or 10%. The sample covers many of the largest glaciers in Norway, and they had an overall change in surface elevation of -15.5 m for the ~50 year period. Converted to a geodetic mass balance this gives a mean mass balance of -0.27 ± 0.05 m w.e. a-1, The dataset of Norwegian glaciers would not be possible without all the observers who helped collecting them. We thank colleagues at NVE, our front position observers and personnel from hydropower companies. We thank Rune V. Engeset, NVE, for providing input to the manuscript. We thank John Brittain, NVE, for English corrections. We thank two anonymous reviewers for input to the manuscript, and editor C. Schneider for handling the manuscript. Statkraft is thanked for partly funding the laser scannings. We thank Trygve Snøtun and Goeffrey D. Corner for providing information on length change advances and records. Torgeir Ferdinand Klingenberg helped digitising some of the glacier outlines. We thank Etienne Berthier for providing Pléiades (@CNES & Airbus D&S) imagery of Svartisen 2016 and processing the data resulting in orthophotos and DTMs. We thank the Norwegian Mapping Authority (Kartverket) for proving orthophotos through norgeibilder.no, a valuable source for glacier status. The work is a contribution to the CryoClim, Svali and Copernicus Glacier Service projects, and internal NVE project ‘Massebalanse’.

The causes underlying Holocene glacier fluctuations remain elusive, despite decades of research efforts. Cosmogenic nuclide dating has allowed systematic study and thus improved knowledge of glacier-climate dynamics during this time frame, in part by filling in geographical gaps in both hemispheres. Here we present a new comprehensive Holocene moraine chronology from Mt. San Lorenzo (47°S) in central Patagonia, Southern Hemisphere. Twenty-four new 10Be ages, together with three published ages, indicate that the Río Tranquilo glacier approached its Holocene maximum position sometime, or possibly on multiple occasions, between 9,860 ± 180 and 6,730 ± 130 years. This event(s) was followed by a sequence of slightly smaller advances at 5,750 ± 220, 4,290 ± 100 (?), 3,490 ± 140, 1,440 ± 60, between 670 ± 20 and 430 ± 20, and at 390 ± 10 years ago. The Tranquilo record documents centennial to millennial-scale glacier advances throughout the Holocene, and is consistent with recent glacier chronologies from central and southern Patagonia. This pattern correlates well with that of multiple moraine-building events with slightly decreasing net extent, as is observed at other sites in the Southern Hemisphere (i.e., Patagonia, New Zealand and Antarctic Peninsula) throughout the early, middle and late Holocene. This is in stark contrast to the typical Holocene mountain glacier pattern in the Northern Hemisphere, as documented in the European Alps, Scandinavia and Canada, where small glaciers in the early-to-mid Holocene gave way to more-extensive glacier advances during the late Holocene, culminating in the Little Ice Age expansion. We posit that this past asymmetry between the Southern and Northern hemisphere glacier patterns is due to natural forcing that has been recently overwhelmed by anthropogenic greenhouse gas driven warming, which is causing interhemispherically synchronized glacier retreat unprecedented during the Holocene.

A linear model was used to investigate the behaviour of the Italian Western Tauri glaciers as a result of temperature changes projected for the 21st century. The model estimates the temperature variations once the glacier snout length variations are known and vice versa: it estimates the glacier snout length variations once the air temperature variations are known or predicted. The 46 glaciers of the Italian Western Tauri, 35 (76%) of which have areas smaller than 0.5 km2 and only 7 (15%) larger than 1 km2, are mostly mountain type glaciers and only three are presently valley glaciers. The model has been forced by the air temperature projections of the A1B emission scenario, which indicates an increase in temperature of 2.7°C from 2015 to 2100. The results show a shortening of more than 35% for mountain glaciers by 2100 with a surface loss of more than 60% and smaller reductions for valley glaciers. The consequent fragmentation into smaller units would lead to the extinction of 95% of the existing glaciers by the end of the century, possibly leaving only the valley glaciers surviving.

On the basis of dendrochronological, lichenometric and historical data with the use of Earth remote sensing materials, the evolution of the Donguz-Orun Glacier has been reconstructed over the past centuries. In this work we used aerial photographs of 1957, 1965, 1981, 1987, satellite image of 2009, as well as descriptions, photographs, maps and plans of the glacier of the 19th and 20th centuries, data of instrumental measurements of the glacier end position in the second half of the 20th – early 21st centuries, dendrochronological dating of pine on the front part of the valley, and juniper to date coastal moraines, and the results of lichenometry studies. It has been established that the Donguz-Orun Glacier in the past had several clearly marked advances about 100, 200 and more than 350 years ago, which are expressed in relief in the form of uneven-aged coastal moraines. Despite the fact that the Donguz-Orun Glacier differs from many mountain-valley glaciers of the Caucasus primarily by its predominantly avalanche feeding and a moraine cover, almost entirely covering its surface, the main periods of its advances are consistent with the known large fluctuations of mountain glaciers during the Little Ice Age in the early 20th, early 19th, and, probably, in the middle of the 17th century. However, unlike most other Caucasian glaciers, the Donguz-Orun Glacier advanced in the 1970s–2000s. Te scale of its degradation from the end of the 19th to the beginning of the 21st century is also uncharacteristic for the Caucasus: the reduction in the length for longer than a century period is only about 100 m.

Fedchenko Glacier experienced a large thickness loss since the first scientific investigations in 1928. As the largest glacier in the Pamir Mountains, this glacier plays an important role for the regional glacier mass budget. We use a series of Global Navigation Satellite Systems observations from 2009 to 2016 and TanDEM-X elevation models from 2011 to 2016 to investigate recent elevation changes. Accounting for radar wave penetration minimizes biases in elevation that can otherwise reach up to 6 m in dry snow on Fedchenko Glacier, with mean values of 3–4 m in the high accumulation regions. The seasonal elevation changes reach up to ±5 m. The glacier surface elevation decreased along its entire length over multi-year periods. Thinning rates increased between 2000 and 2016 by a factor of 1.8 compared with 1928–2000, resulting in peak values of 1.5 m a−1. Even the highest accumulation basins above 5000 m elevation have been affected by glacier thinning with change rates between −0.2 and −0.4 m a−1 from 2009 to 2016. The estimated glacier-wide mass-balance rates are −0.27 ± 0.05 m w.e. a−1 for 2000 to 2011 and −0.51 ± 0.04 m w.e. a−1 between 2011 and 2016.

The Lower Grindelwald Glacier (Bernese Oberland, Switzerland) consists of two parts, the Ischmeer in the east (disconnected) and the Bernese Fiescher Glacier in the west. During the Little Ice Age (LIA), the glacier terminated either in the area of the “Schopffelsen” (landmark rock terraces) or advanced at least six times (ten times if we include early findings) even further down into the valley bottom forming the “Schweif” (tail). Maximal ice extensions were reached in 1602 and 1855/56 AD. The years after the end of the LIA have been dominated by a dramatic melting of ice, especially after 2000. The Mer de Glace (Mont Blanc area, France) is a compound valley glacier formed by the tributaries Glacier du Tacul, Glacier de Léschaux, and Glacier de Talèfre (disconnected). During the LIA, the Mer de Glace nearly continuously reached the plain in the Chamonix Valley (maximal extensions in 1644 and 1821 AD). The retreat, beginning in the mid-1850s, was followed by a relatively stable position of the front (1880s until 1930s). Afterwards the retreat has continued until today, especially impressive after 1995. The perception of glaciers in the early times was dominated by fear. In the age of Enlightenment and later in the 19th century, it changed to fascination. In the 20th century, glaciers became a top attraction of the Alps, but today they are disappearing from sight. With a huge number of high-quality pictorial documents, it is possible to reconstruct the LIA history of many glaciers in the European Alps from the 17th to the 19th centuries. Thanks to these pictures, we get an image of the beauty and fascination of LIA glaciers, ending down in the valleys. The pictorial documents (drawings, paintings, prints, photographs, and maps) of important artists (Caspar Wolf, Jean-Antoine Linck, Samuel Birmann) promoted a rapidly growing tourism. Compared with today’s situations, it gives totally different landscapes – a comparison of LIA images with the same views of today is probably the best visual proof for the changes in climate.

The recession of mountain glaciers worldwide is increasing global sea level and, in many regions, human activities will have to adapt to changes in surface hydrology. Thus, it is important to provide up-to-date analyses of glacier change and the factors modulating their response to climate warming. Here we report changes in the extent of >120 glaciers on the Lyngen Peninsula, northern Norway, where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred. Glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988, 2001 and a new one from 2014, and previously-dated Little Ice Age (LIA) limits. Results show a steady reduction in area (~0.3% a−1) between their LIA maximum (~1915) and 1988, consistent with increasing summer air temperatures, but recession paused between 1988 and 2001, coinciding with increased winter precipitation. Air temperatures increased 0.5°C per decade from the 1990s and the rate of recession accelerated to ~1% a−1 between 2001 and 2014 when glacier area totalled ~95.7 km2. Small glaciers (2) with low maximum elevations (

Cosmogenic exposure dating is one of the most widely used methods to constrain the deglaciation history of former glaciated areas. In Greenland, more than 1000 cosmogenic 10Be exposure ages (10Be ages) have been published within the last two decades. However, a recurring problem is that many of these studies have reported variable amounts of nuclide inheritance making the 10Be ages too old and difficult to assess without large datasets or independent age control. In this study, we test the accuracy of 10Be dating of Holocene moraines using independent age constraints from threshold lake records. In Kangerlussuaq, West Greenland, the 10Be ages of the Ørkendalen moraine system are highly clustered with a mean age of 6.8 ± 0.3 ka (no outliers). In contrast, the nearby Little Ice Age (LIA) moraine yields scattered 10Be ages ranging from 2.5 to 0.1 ka but with a mean of 0.18 ± 0.06 ka after excluding outliers which coincides with independent age constraints from threshold lakes and boulder kill dates. At Gletscherlukket, Southeast Greenland, the 10Be ages of the LIA moraine range from 10.2 to 1.6 ka with a mean of 1.9 ± 0.2 ka after excluding outliers. This is ~1.7 ka older than recorded in the proglacial threshold lakes and suggests that all samples from this site contain a significant amount of nuclide inheritance. Our results are consistent with other reports of skewed 10Be age distributions in LIA re-advance moraines and it probably reflects nuclide inheritance from exposure during the Holocene Thermal Maximum when the glaciers in Greenland were inside the LIA extent. In contrast, there is no evidence of nuclide inheritance in the Ørkendalen moraines, most likely because the glacial erosion was more intense prior to the formation of the moraines i.e. sometime between the advance phase during Last Glacial Maximum position and the subsequent lateglacial and Holocene deglaciation. Our results highlight a potential pitfall related to dating re-advance moraines using cosmogenic exposure dating and we recommend using a multi-method dating approach.

Two major climatic phenomena that occurred during the Holocene are interpreted from the resonance in subharmonic modes of long-period Rossby waves winding around the North Atlantic gyre, the so-called gyral Rossby waves (GRWs). These are, on the one hand, the change in atmospheric circulation that occurred in the North Atlantic in the middle Holocene, and, on the other hand, the occurrence of abrupt cooling events more frequently than what is generally accepted. The amplitude of GRWs is deduced by filtering, within bands characteristic of various subharmonic modes, climate records from the Greenland ice sheet, pollen, and tree rings in northern Fennoscandia, and from two Norwegian glaciers in northern Folgefonna and on the Lyngen peninsula. While the subharmonic modes reflect the acceleration/deceleration phases of the western boundary current, an anharmonic mode is evidenced in the 400–450 year band. Abrupt cooling events of the climate are paced by this anharmonic mode while the western boundary current is decelerating, and the northward heat advection of air favors the melting of the pack ice. Then, the current of the northernmost part of the North Atlantic gyre cools before branching off to the north, which alters its buoyancy. On the other hand, according to high subharmonic modes, high-pressure systems prevailed over the North Atlantic in the first half of the Holocene while low-pressure systems resulted from baroclinic instabilities of the atmosphere dominate during the second half, favoring the growth of glaciers in Scandinavia by a better snowfall in winter and cooler summers.

Accelerating ice loss during recent years has made the Greenland Ice Sheet one of the largest single contributors to global sea level rise, accounting for 0.5 of the total 3.2 mm yr −1 . This loss is predicted to continue and will most likely increase in the future as a consequence of global warming. However, the sensitivity of glaciers and ice caps (GICs) in Greenland to prolonged warm periods is less well constrained and geological records documenting the long-term glacial history are needed to put recent observations into a broader perspective. Here we report the results from three proglacial lakes where fluctuations in local glaciers located at different altitudes in Kobbefjord, southwest Greenland have been recorded. Our results show that the lakes received meltwater from the initial deglaciation of the area ∼9.2 cal. ka BP until ∼8.7–7.9 cal. ka BP when the meltwater input ceased as the glaciers most likely disappeared. Regrowth of glaciers began again at ∼5.5 cal. ka BP at ∼1370 m a.s.l., ∼3.6 cal. ka at ∼1170 m a.s.l., and ∼1.6 cal. ka BP at ∼1000 m a.s.l., clearly reflecting strong altitudinal control of the GIC response to Neoglacial cooling. Our results highlight that GICs in Kobbefjord, southwest Greenland are primarily influenced by changes in summer air temperatures and winter precipitation and that they are facing a rapid decay that most likely will result in their disappearance within the next centuries as a consequence of global warming. If current 21st Century retreat rates continue, the GICs in the study area will be completely gone in ∼30–90 years, with the smallest GICs disappearing first.

To improve our knowledge of glacier area changes in the central Chilean and Argentinean Andes (32°9′S–33°4′S), two new glacier inventories from 1989 to 2013/14 are compared with a reinterpreted inventory from 1955. Comparisons show glacier area retreat of 30 ± 3% since 1955, decreasing from 134 to 94 km2 in 2013/14, whilst the annual rate of area loss showed a small increase (insignificant) between the periods of 1955–1989 and 1989–2013/14. Separate analysis of the 1989 and 2013/14 inventories, including a larger sample, revealed a higher rate of glacier change compared with the smaller samples of these inventories. Additionally, an analysis at ~5 year intervals for six major glaciers (1955–2013) indicates large variability in response times and area loss magnitudes. Glacier Olivares Alfa, for example, lost 63% of its ice area, while the Juncal Norte Glacier lost only 10% (1955–2013). The findings from this study improve our current knowledge base concerning widespread glacier decline in the southern Andes, and furthers monitoring efforts in this poorly described region of the world, a region containing vital water resources for populated areas in South America.

Fedchenko glacier is by far the largest glacier in the Pamir, Tajikistan. Owing to early accurate mapping of the glacier it is possible to evaluate glacier changes over eight decades, which is an exceptionally long time period for this remote mountain region. During this time a total volume loss of 5 km3 was observed on the main trunk of the glacier, while the total area changed by only 1.4%. It is observed that the volume loss migrates from the lower parts of the glacier towards the upper ablation zone. The comparatively small change in area is a result of the supraglacial debris cover on the glacier tongue, which decouples the area loss from the volume loss to a considerable degree. The observed velocities of the glacier do not reflect the volume changes up to now because the interannual variability is larger than possible long-term changes so far. The intra-annual velocity distribution in the central ablation zone probably reflects the evolution of the basal drainage system. Based on ice thickness measurements and simple ice-dynamic assumptions, the total volume of Fedchenko glacier is 123.4 ± 8 km3.

In this study, contour lines from the topographic maps at a 1:100,000 scale (mapped in 1968), Landsat MSS/TM/OLI images, ASTER images and SPOT 6-7 stereo image pairs were used to study changes in glacier length, area and surface elevation. We summarized the results using the following three conclusions: (1) During the period from 1973 to 2013, glaciers retreated by 412 &plusmn, 32 m at a mean retraction rate of 10.3 &plusmn, 0.8 m&middot, year&minus, 1 and the relative retreat was 5.6 &plusmn, 0.4%. The glacier area shrank by 7.5 &plusmn, 3.4%, which was larger than the glacier length. In the periods of 1968&ndash, 2000, 2000&ndash, 2005 and 2000&ndash, 2013, the glacier surface elevation change rates were &minus, 7.7 &plusmn, 1.4 m (&minus, 0.24 &plusmn, 0.04 m&middot, 1), &minus, 1.9 &plusmn, 1.5 m (&minus, 0.38 &plusmn, 0.25 m&middot, 1) and &minus, 5.0 &plusmn, 0.11 m&middot, 1), respectively. The changes in the glacier area and thickness exhibited similar trends, both showing a significant increasing reduction after 2000. (2) Eleven glaciers were identified as surging glaciers. Changes of the mass balance in surging glaciers were stronger than in non-surging glaciers between 1968 and 2013. Changes of area in surging glaciers were weaker than in non-surging glaciers. (3) Increasing temperature was the major cause of glacier thickness reduction and area shrinkage. The increase in precipitation, to a certain extent, inhibited glacial ablation but it did not change the status of the shrinkage in the glacial area and the reduction in the glacier thickness.

Cosmic-ray exposure (CRE) dating of moraines allow glacier fluctuations and past climate change reconstructions. In the French Alps, there is a lack of moraine dating for the Late Glacial/Holocene transition period. Here we present a chronology of glacier advances in the Upper Romanche valley (French Alps - Massif des Ecrins) based on Be-10 CRE dating. CRE ages of moraines of 13.0 +/- 1.1 ka and 12.4 +/- 1.5 ka provide evidence for two stages of glacial advance or standstill at the end of the Late Glacial. The CRE dating of a rock avalanche deposit at 12.2 +/- 1.5 ka is attributed to post-glacial debuttressing and reveals rapid deglaciation at the end of the Late Glacial. A CRE age of 7.1 +/- 0.7 ka of a second mass wasting, whose triggering factor is unidentified so far, indicates that up to an altitude of 2300 m a.s.l., the valley was ice-free as of similar to 7 kyr at the latest. The re-evaluation of 21 moraine Be-10 CRE ages from nine glacial valleys across the Alps shows multiple glacial advances occurring at the Late Glacial/Holocene transition. These results lead to a re-evaluation of the importance of cooling events during the Allerod and the Younger Dryas in the Alps.

11 páginas, 5 figuras, 2 tablas., A multidisciplinary study including sedimentological, mineral magnetic, and palaeobotanical techniques applied to a sediment core recovered from proglacial Lake Barrancs in the seismically active Maladeta Massif has provided the basis for documenting environmental changes and palaeoseismic activity in the Central Pyrenees for the last ca. 3700 yr. Lake Barrancs is located downstream of the Tempestats and Barrancs cirque glaciers and sedimentation is dominated by clastic input corresponding to seasonal changes in sediment supply. Slow fine particle settling during the winter and sediment-loaded homopycnal flows during the warm season, triggered by snow-melting and glacier outwash, have resulted in deposition of rhythmites composed of clays, silts, and sands. The predominance of finer-grained sediments and the low concentration of relatively finer magnetite grains suggest that glacier activity was very small, if not absent, before ca. A.D. 350. Their replacement by coarser-grained sediments and the overall increased (but highly oscillating) concentrations of relatively coarser magnetite grains in the uppermost 4.3 m of the record suggest the onset of glacial activity and enhanced snow-melting in the catchment of Lake Barrancs after A.D. 350. We suggest that this onset of glacial and enhanced snow-melt activity was driven by a complex balance between winter precipitation and annual mean temperatures, among other climatic variables. Peat layers suggest two dramatic lake-level drops at A.D. 300 and A.D. 450, when Lake Barrancs was drained. The mechanisms for such extreme hydrological events are not clear. Changes in the precipitation/evaporation ratio cannot account for such desiccation events. Dam failure is unlikely since there are no geomorphological evidence of breaching processes. Geomorphological and structural evidence demonstrates active faulting since formation of Lake Barrancs and reactivation during earthquake shaking. Based on this, we propose an alternative explanation for the desiccation events that involves the draining of the lake through pre-existing fractures opened by earthquakes. Further studies in Lake Barrancs and other lakes from the Maladeta massif are necessary to validate the hypotheses presented here concerning the response of glacial and snow-melt activity to climate variability and the palaeoseismic record of the Central Pyrenees., This research was supported by projects AMB93-0814-C02-01 and PB96-0815, and by a MEC Ramón y Cajal contract (JCL).

A new lichen dating method and new moraine observations enabled us to improve the chronology of glacier advances in the Cordillera Blanca (Peru) during the Little Ice Age (LIA). Our results reveal that an early LIA glacial advance occurred around AD 1330 +/- 29. However, a second major glacial advance at the beginning of the 17th century overlapped the earlier stage for most glaciers. Hence, this second glacial stage, dated from AD 1630 +/- 27, is considered as the LIA maximum glacial advance in the Cordillera Blanca. During the 17th-18th centuries, at least three glacial advances were recorded synchronously for the different glaciers (AD 1670 +/- 24, 1730 +/- 21, and 1760 +/- 19). The moraines corresponding to the two first stages are close to the one in 1630 suggesting a slow recession of about 18% in the total length of the glacier. From the LIA maximum extent to the beginning of the 20th century, the 24 glaciers have retreated a distance of about 1000 in, corresponding to a reduction of 30% in their length. This rate is comparable to that observed during the 20th century. Estimates of palaeo-Equilibrium Line Altitudes show an increase in attitude of about 100 m from the LIA maximum glacial extension at the beginning of the 17th century to the beginning of the 20th century. Because long time series are not available for precipitation and temperature, this glacial retreat is difficult to explain by past climate changes. However, there is a fair correspondence between changes in glacier length and the delta O-18 recorded in the Quelccaya ice core at a century timescale. Our current knowledge of tropical glaciers and isotope variations leads us to suggest that this common tropical signal reflects a change from a wet LIA to the drier conditions of today. Finally, a remarkable synchronicity is observed with glacial variations in Bolivia, suggesting a common regional climatic pattern during the LIA.

Discharge from marine-terminating outlet glaciers accounts for up to half the recent mass loss from the Greenland ice sheet, yet the causal factors are not fully understood. Here we assess the factors controlling the behaviour of Humboldt Glacier (HG), allowing us to evaluate the influence of basal topography on outlet glacier response to external forcing since part of HG’s terminus occupies a large overdeepening. HG’s retreat accelerated dramatically after 1999, coinciding with summer atmospheric warming of up to 0.19°C a–1 and sea-ice decline. Retreat was an order of magnitude greater in the northern section of the terminus, underlain by a major basal trough, than in the southern section, where the bedrock is comparatively shallow. Velocity change following retreat was spatially non-uniform, potentially due to a pinning point near HG’s northern lateral margin. Consistent with observations, numerical modelling demonstrates an order-of-magnitude greater sensitivity to sea-ice buttressing and crevasse depth (used as a proxy for atmospheric warming) in the northern section. The trough extends up to 72 km inland, so it is likely to facilitate sustained retreat and ice loss from HG during the 21st century.

The Miage amphitheatre is an original form of the morainic complex of one of the main Italian glaciers, located on the southeast side of the Mont Blanc massif. This form was studied since the end of the last century, especially by italian authors. Our study combines morainic geometry analysis with dating methods (dendrochronology, lichenometry, radiodatation, soil analysis) to build a model for the amphitheatre setting up. This model describes a succession of glacier overflowing phases over the right lateral moraine and of heightening phases of this moraine (by superposition). This occurs during the Late Holocene (the last three millenniums), except the morainic amphitheatre base, which is older. The Litte Ice Age contribution to the amphitheatre formation, considered as essential by some authors, is precised., Résumé L'amphithéâtre du Miage est un élément original du complexe morainique de l'un des principaux glaciers italiens, situé sur le versant sud-est du massif du Mont Blanc. Il a constitué un objet d'étude dès la fin du XIXe siècle, en particulier pour les auteurs italiens. Notre recherche s'est attachée à confronter la géométrie des moraines et des moyens de datation (dendrochronologie, lichénométrie, datation radiocar- bone, analyse des sols) pour aboutir à un schéma de la mise en place de l'amphithéâtre morainique. Les modalités de celle-ci consistent essentiellement en une succession de phases de débordement du glacier par-dessus sa moraine latérale droite et de réhaussements de cette dernière par apports détritiques successifs (superposition). La chronologie de ces phases appartient à l'Holocène récent, Le. les trois derniers millénaires, compte non tenu du soubassement de la partie inférieure de l'amphithéâtre morainique. Le rôle du Petit Âge Glaciaire dans la formation de ce dernier, tenu pour essentiel par certains auteurs, est relativisé : seuls les cordons morainiques entourant immédiatement le lac peuvent être rapportés à cette période., Deline Philip. La mise en place de l'amphithéâtre morainique du Miage (Val Vény, Val d'Aoste)/The setting up of the Miage morainic amphitheatre (Val Vény, Valley of Aosta). In: Géomorphologie : relief, processus, environnement, Avril 1999, vol. 5, n°1. pp. 59-72.

One of the main italian glaciers, the Miage glacier is located on the southeast side of the Mont Blanc massif. Its front reaches an elevation of 1750 m in the Val Veny. Characteristics of the Miage are : debris cover glacier, which smoothes over the fluctuations ; huge lateral moraines (150 m high) ; morainic amphitheatre around the juxtaglacial Miage lake. With Present fluctuations (since 1860) of small amplitude, the Miage glacier is atypical. Various data (moraine geometry, pedology, iconography, radiocarbon dating, lichenometry, dendrochronology) are used to reconstitue several Miage advances during the Little Ice Age (LIA). This study - contrary to some authors - considers that the LIA plays a small part in the Miage morainic complex setting up. Several elements about the amphitheatre and the lateral morames suggests that their genesis is very former to Göschenen 2 for this one, to the Central Middle Ages for that ones., Situé sur le versant sud-est du massif du Mont Blanc, le glacier du Miage est l'un des principaux glaciers italiens. Son front atteint 1750 m d'altitude dans le Val Veny. Le Miage se caractérise par sa qualité de glacier noir (filtrage des variations), ses moraines latérales de grande dimension (150 m de commandement) et son amphithéâtre morainique autour du lac du Miage. Les variations actuelles (depuis 1860) sont de faible amplitude, ce qui fait du Miage un glacier au comportement atypique. Divers arguments (géométrie des moraines, pédologie, documents anthropiques, radiodatations, lichénométrie, dendrochronologie) permettent de reconstituer plusieurs des avancées du Miage lors du Petit Âge Glaciaire (PAG). Cette étude montre que bien que certains auteurs attribuent la mise en place de la plus grande partie du complexe morainique du Miage au PAG, celui-ci n'y entre en fait que pour une faible part. Plusieurs éléments concernant l'amphithéâtre et les moraines latérales montrent que leur genèse est très antérieure au Göschenen 2 pour le premier, au Moyen Âge central pour les secondes., Deline Philip. Les variations holocènes récentes du glacier du Miage (Val Veny, Val d'Aoste) [Late holocène fluctuations of the Miage glacier (Val Veny, Valley of Aosta)]. In: Quaternaire, vol. 10, n°1, 1999. pp. 5-13.

This overview, or retrospective, has two objectives. The first is to demonstrate how the principles of ‘mountain geoecology’ were applied in an attempt to counteract the political and socio-economic impacts of a major and misguided environmental orthodoxy-the Theory of Himalayan Environmental Degradation (henceforth to be referred to as the ‘Theory’). The second is to explore the difficulties of transferring the results of on-going scholarly mountain research into the public and political decision-making process. In this sense the paper should be regarded as a case study of the potentially serious effects of exaggerated and emotionally based responses to orthodoxies founded on assumptions and latter-day myths. A third objective, reserved for the companion paper in this issue, outlines the origins of mountain geoecology and explores how academic research influenced the inclusion of high level concern for mountain problems within AGENDA 21, one of the principal results of the 1992 UN Conference on Environment and Development (popularly known as the Rio Earth Summit) and declaration of 2002 as the International Year of Mountains. The original environmental orthodoxy (the Theory) has been eclipsed since the turn of the Millennium by a new populist alarm proposing that the current climate warming will cause all the Himalayan glaciers to disappear in the near future. From this it would follow that, as the glacier melt progresses, numerous large glacial lakes, forming as a consequence, would burst and the ensuing floods would annihilate many millions of people. Eventually, as the glaciers disappeared vital rivers, such as the Ganges and Brahmaputra, would wither to seasonal streams heralding further massive loss of life due to desertification and starvation. This current environmental alarm could be regarded as a present day parallel to the original Theory and will be examined in the final section of the paper. Between 1970 and about 1985 it was almost universal wisdom amongst scholars and development specialists, as well as conservationists, that the Himalaya were on the brink of environmental, and hence socio-economic and political collapse. This theme of gloom and doom was taken up avidly by journalists, politicians, and diplomats; it influenced the expenditure of large sums of aid and development money, and augmented periodic international confrontations. In concise terms, in the early 1970s an assumed approaching environmental disaster was perceived to be driven by relentless growth in the population of subsistence hill communities and their dependence on mountain forests for fuel, fodder, building materials, and conversion to agricultural land. The assumption of rapid and catastrophic deforestation of steep hillslopes under a monsoon climate (the World Bank predicted that there would be no accessible forest remaining in Nepal by the year 2000) led inexorably to a series of dependent assumptions: increasing soil erosion and worsening landslide incidence; accelerated flooding and siltation on the plains of Gangetic India and Bangladesh; social and political unrest, if not serious armed conflict – the notion of a world super-crisis, considering that the region in question contained about ten percent of the world’s entire human population and about thirty percent of its poorest. As will be emphasized later, none of this all-embracing construct was based on reliable evidence, but it was accepted world-wide as a given. It represents a prime example of the dangers associated with convenient adoption of environmental myths, or environmental orthodoxies, especially where the myth is a Western ‘scientific’ construct. I characterized it as The Theory of Himalayan Environmental Degradation (Ives, 1985)., Esta perspectiva global, o retrospectiva, tiene dos objetivos. El primero es demostrar cómo se aplicaron los principios de la “geoecología de montaña” en un intento por contrarrestar los impactos políticos y socioeconómicos de una errónea ortodoxia ambiental, la Teoría de la Degradación Ambiental del Himalaya (en adelante referida como la “Teoría”). El segundo es explorar las dificultades para transferir los resultados de la investigación científica en montaña a los procesos públicos de decisión. En este sentido, el artículo debería ser contemplado como un estudio de caso de los efectos potencialmente serios de las exageradas respuestas a las ortodoxias basadas en suposiciones y mitos de última hora. Un tercer objetivo, reservado a otro trabajo publicado en este volumen, subraya los orígenes de la geoecología de montaña y explora cómo la investigación académica influyó en la incorporación de la preocupación por los problemas de la montaña en la AGENDA 21, uno de los principales resultados de la Conferencia de Naciones Unidas de 1992 sobre Medio Ambiente y Desarrollo (popularmente conocida como la Cumbre de Río), y la declaración de 2002 como el Año Internacional de las Montañas. La ortodoxia ambiental original (la Teoría) ha sido eclipsada desde el cambio de milenio por una nueva alarma populista que propone que el actual calentamiento climático hará que todos los glaciares del Himalaya desaparezcan en un futuro próximo. De ahí puede deducirse que, a medida que la fusión glaciar progrese, numerosos lagos glaciares reventarían y las consiguientes avenidas aniquilarían a millones de personas. Eventualmente, tras la desaparición de los glaciares, algunos ríos fundamentales, como el Ganges y el Brahmaputra podrían convertirse en ríos estacionales ocasionando la pérdida masiva de vidas humanas debido a la desertificación y el hambre. Esta alarma ambiental podría ser vista como paralela a la Teoría original, y será examinada en la parte final de este artículo. Entre 1970 y 1985 se mantuvo la opinión entre los científicos y especialistas en desarrollo, así como entre los conservacionistas, de que el Himalaya estaba al borde del colapso ambiental, socioeconómico y político. Este pesimismo y predestinación fue adoptado ávidamente por periodistas, políticos y diplomáticos, e influyó en la dedicación de grandes sumas de dinero y ayudas. En pocas palabras, a comienzos de los años setenta se asumió la ocurrencia de un desastre ambiental determinado por el crecimiento demográfico de comunidades que dependían de los bosques de montaña para la obtención de energía, forraje, materiales de construcción y expansión de los terrenos agrícolas. La asunción de una rápida y catastrófica deforestación de laderas pendientes bajo clima monzónico (el Banco Mundial predijo que no habría bosques accesibles en Nepal hacia el año 2000) condujo inexorablemente a aceptar otras suposiciones: aumento de la erosión del suelo y acentuación de la incidencia de los deslizamientos; incremento de la magnitud y frecuencia de las avenidas y del transporte de sedimento en las llanuras del Ganges en India y Bangladesh; conflictividad social y política, cuando no serios conflictos armados, es decir, la noción de una supercrisis mundial, teniendo en cuenta que la región en cuestión contiene alrededor del 10 por ciento de la población mundial y alrededor de la tercera parte de los más pobres. Como se pone de relieve a continuación, ninguna de esas ideas se basaba en evidencias fiables, pero fueron aceptadas mundialmente como un hecho. Representan un ejemplo claro de los peligros asociados a la adopción de mitos u ortodoxias ambientales, especialmente donde el mito es una construcción “científica” del mundo occidental. Yo la definí como la Teoría de la Degradación Ambiental del Himalaya (Ives, 1985).

The aim of this paper is to document the evolution of glaciers in the tropical Andes (between 10 degrees N and 16 degrees S) for the last millennium, based on moraines dated by lichenometry and radiocarbon, lake sediment records and historical documents. Viewed collectively, several glacial advances occurred synchronously. The first advance is dated around AD 1200-1350. The maximum glacial extent (MGE), defined as the furthest down-valley extent recorded synchronously by the majority of glaciers, occurred around 1630-1680 in Bolivia and Peru (the outer tropics) and around AD 1730 in Ecuador, Colombia and Venezuela (the inner tropics). Subsequently. during the 18th and 19th centuries, glaciers retreated continuously with only minor synchronous readvances. In the outer tropics, minor glacial advances occurred around 1730,1760,1800,1850, and 1870. In the inner tropics, synchronous minor advances occurred around 1760,1820 and 1880. Between the MGE and the early 20th century, glaciers lost about 30% of their total length. The retreat was slow between the 17th and 18th centuries but then became more marked. Use of the accumulation area ratio (AAR) method or historical observations in the different cordilleras revealed an increase in the equilibrium line altitude (ELA) of about 300 m from the MGE onward. Palaeoclimatic hypotheses, based on glaciological models run in different countries, suggest a cool and humid period in the 16-18th centuries followed by a colder and drier period in the 19th century. The reduction of glaciers observed from the middle of the 19th century is due to increasingly warmer conditions than before. Here, quantitative estimates are proposed to explain the evolution of the glaciers. In Venezuela, results indicate for the period 1250-1820 that mean air temperatures were 3.2 +/- 1.4 degrees C cooler and precipitation was about 22% higher than at present. In Ecuador, temperatures of between 0.8 degrees and 1.1 degrees C lower than today, and between 25% and 35% higher accumulation than today, appear to have occurred in the 18th century, followed by a short drier but colder period at the beginning of the 19th century. In Bolivia, the MGE could be a consequence of a decrease in temperature of 1.1 to 1.2 degrees C, and a 20 to 30% increase in accumulation or an increase in cloudiness of about 1-2/10. We discuss not only external climatic forcing but also the coincidence between glacier expansion and a decrease in solar irradiance. Dating uncertainties, however, have made the role of volcanism in glacier fluctuations impossible to determine. Finally, we discuss the relationships between ENSO and glacier fluctuations in recent centuries, which do not match directly with current knowledge of modern teleconnections between tropical Pacific SSTs and variations in glacier mass balance.

Dating moraines by lichenometry enabled us to reconstruct glacier recession in the Bolivian Andes since the Little Ice Age maximum. On the 15 proglacial margins studied, we identified a system of tell principal moraines that marks the successive positions of glaciers over the last four Centuries. Moraines were dated by perl'onning statistical analysis of lichen rneaSUrenients based on the extrerne values theory. Like glaciers ill many mid-latitude mountain areas, Bolivian glaciers reached their maximal extent during the second half of the 17th century. This glacier maximum coincides with the Maunder minimum of solar irradiance. By reconstructing the equilibrium-line altitude and changes in mass-balance, we think the glacier maximum may be due to a 20 to 30% increase in precipitation and a 1.1 to 1.2 degrees C decrease in temperature compared with present conditions. In the early 18th century, glaciers started to retreat at varying rates until the late 19th to early 20th century; this trend was generally associated with decreasing accumulation rates. By contrast, glacier recession in the 20th century was mainly the consequence of an increase in temperature and humidity. These results are consistent with observations made ill the study region based on other proxies.

In this article we present the reconstruction of fluctuations of Alibek valley glacier situated in the Teberda valley, Western Caucasus. The former positions of glacier of the past 120 years were reconstructed basing on the old photographs of 1904, 1921, remote sensing data of 1955, 1987, 2007, 2008 and 2012, plans created in 20th century. Since the middle of 20th century Alibek Glacier decreased by 650 m in length and by 0,67 km2 in area and its tongue has risen by 110 m.

This research examines moraine and lacustrine records of glacier fluctuations, in combination with palynological records of vegetation change, from the previously unstudied northwestern Ahklun Mountains in southwestern Alaska. Morain mapping reveals that ice-cap outlet glaciers in the study area extended ca. 60 km from the center of the Ahklun Mountians ice dome during the early Wisconsin (sensu lato), and ca. 40 km during the late Wisconsin. Correlations with well-studied moraines in the southern Ahklun Mountains indicate an asymmetry of glaciation over the range, with ice-cap outlet glaciers more extensive to the south. This asymmetry was more striking during the early Wisconsin (s.l.) than during the late Wisconsin. Alpine glaciers have repeatedly advanced from cirques within the study area. Because these alpine glaciers were confluent or sub-confluent with outlet glaciers during the late Wisconsin maximum, the alpine-glacier moraine record is relatively young. Lacustrine sedimentology from Little Swift Lake records significant retreat of alpine glaciers ca 12.8 ka (coeval with the onsent of the North Atlantic Younger Dryas). Moraines upvalley of the lake suggests a minor glacier (or rock glacier) advance occurred ca 5.5 ka. Lacustrine records of vegetation from Little Swift Lake extend back to ca. 13.4 ka. Most vegetation changes resulted from the post-glacial spread of trees and shrubs, including Betula, alnus, and Picea, to their modern ranges. However, pollen assemblages and other paleoclimate proxies suggest some major changes in late-glacial and Holocene climate. Major vegetation change, most notably the dramatic expansion of Poaceae, occurred ca. 100 yr after the 12.8-ka glacier retreat and persisted for more than 2 ka. The inferred reversal to dry (and possibly cool) climate was followed by a period of exceptionally productive mesic conditions during the early Holocene, ca. 11 to 9 ka. The pattern of latest-Quaternary climate changes documented in this study may be evidence that, as previous workers have concluded regarding the Pleistocene glaciations, the late-glacial and early Holocene climate of the Ahklun Mountains region was strongly modulated by changes in the proximity and temperature of the Bering Sea.