Large freshwater lakes formed in North America and Europe during deglaciation following the Last
Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in
climate, including the Younger Dryas and 8.2 kyr cooling events. In the mid-latitudes of the Southern
Hemisphere, major glacial lakes also formed and drained during deglaciation but little is known
about the magnitude, organization and timing of these drainage events and their effect on regional
climate. We use 16 new single-grain optically stimulated luminescence (OSL) dates to define three
stages of rapid glacial lake drainage in the Lago General Carrera/Lago Buenos Aires and Lago Cohrane/
Pueyrredón basins of Patagonia and provide the first assessment of the effects of lake drainage on the
Pacific Ocean. Lake drainage occurred between 13 and 8 kyr ago and was initially gradual eastward into
the Atlantic, then subsequently reorganized westward into the Pacific as new drainage routes opened
up during Patagonian Ice Sheet deglaciation. Coupled ocean-atmosphere model experiments using
HadCM3 with an imposed freshwater surface “hosing” to simulate glacial lake drainage suggest that
a negative salinity anomaly was advected south around Cape Horn, resulting in brief but significant
impacts on coastal ocean vertical mixing and regional climate.

Glacier- and snowpack-derived meltwaters are threatened by climate change. Features such as rock glaciers (RGs) are climatically more resilient than glaciers and potentially contain hydrologically valuable ice volumes. However, while the distribution and hydrological significance of glaciers is well studied, RGs have received comparatively little attention. Here, we present the first near-global RG database (RGDB) through an analysis of current inventories and this contains >73,000 RGs. Using the RGDB, we identify key data-deficient regions as research priorities (e.g. Central Asia). We provide the first approximation of near-global RG water volume equivalent and this is 83.72 ± 16.74 Gt. Excluding the Antarctic and Subantarctic, Greenland, and regions lacking data, we estimate a near-global RG to glacier water volume equivalent ratio of 1:456. Significant RG water stores occur in arid and semi-arid regions (e.g. South Asia East, 1:57). These results represent a first-order approximation. Uncertainty in the water storage estimates includes errors within the RGDB, inherent flaws in the meta-analysis methodology, and RG thickness estimation. Here, only errors associated with the assumption of RG ice content are quantified and overall uncertainty is likely larger than that quantified. We suggest that RG water stores will become increasingly important under future climate warming.

© 2018 the Authors the prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

Large freshwater lakes formed in North America and Europe during deglaciation following the Last
Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in
climate, including the Younger Dryas and 8.2 kyr cooling events. In the mid-latitudes of the Southern
Hemisphere, major glacial lakes also formed and drained during deglaciation but little is known
about the magnitude, organization and timing of these drainage events and their effect on regional
climate. We use 16 new single-grain optically stimulated luminescence (OSL) dates to define three
stages of rapid glacial lake drainage in the Lago General Carrera/Lago Buenos Aires and Lago Cohrane/
Pueyrredón basins of Patagonia and provide the first assessment of the effects of lake drainage on the
Pacific Ocean. Lake drainage occurred between 13 and 8 kyr ago and was initially gradual eastward into
the Atlantic, then subsequently reorganized westward into the Pacific as new drainage routes opened
up during Patagonian Ice Sheet deglaciation. Coupled ocean-atmosphere model experiments using
HadCM3 with an imposed freshwater surface “hosing” to simulate glacial lake drainage suggest that
a negative salinity anomaly was advected south around Cape Horn, resulting in brief but significant
impacts on coastal ocean vertical mixing and regional climate.

Glacier- and snowpack-derived meltwaters are threatened by climate change. Features such as rock glaciers (RGs) are climatically more resilient than glaciers and potentially contain hydrologically valuable ice volumes. However, while the distribution and hydrological significance of glaciers is well studied, RGs have received comparatively little attention. Here, we present the first near-global RG database (RGDB) through an analysis of current inventories and this contains >73,000 RGs. Using the RGDB, we identify key data-deficient regions as research priorities (e.g. Central Asia). We provide the first approximation of near-global RG water volume equivalent and this is 83.72 ± 16.74 Gt. Excluding the Antarctic and Subantarctic, Greenland, and regions lacking data, we estimate a near-global RG to glacier water volume equivalent ratio of 1:456. Significant RG water stores occur in arid and semi-arid regions (e.g. South Asia East, 1:57). These results represent a first-order approximation. Uncertainty in the water storage estimates includes errors within the RGDB, inherent flaws in the meta-analysis methodology, and RG thickness estimation. Here, only errors associated with the assumption of RG ice content are quantified and overall uncertainty is likely larger than that quantified. We suggest that RG water stores will become increasingly important under future climate warming.

During the Last Glacial Maximum (LGM), the Patagonian Ice Sheet (PIS) was the largest Quaternary ice mass in the Southern Hemisphere outside of Antarctica. Although the margins of the LGM ice sheet are now well established through end-moraine mapping and dating, apart from a few modelling and empirical studies, there remains a lack of constraint on its thickness and three-dimensional configuration. Here, we provide a high-resolution steady-state model reconstruction of the PIS at its maximum - LGM - extent applied using Nye's perfect-plastic ice rheology. The yield-strength parameter for the perfect-plastic flow model was calibrated against independent empirical reconstructions of the Lago Pueyrredón Glacier, where the former vertical extent of this major outlet glacier is well constrained by cosmogenically-dated trimlines and lateral and end-moraine limits. Using this derived yield-strength parameter, the perfect-plastic model is then applied to multiple flowlines demarking each outlet across the entirety of the PIS in a GIS framework. Our results reveal that the area of the PIS was ∼504,500 km2 (±8.5%) with a corresponding modelled ice volume of ∼554,500 km3 (±10%), equivalent to ∼1.38 m (±10%) of eustatic sea-level lowering at the LGM. Maximum surface elevation was at least 3500m asl although the majority of the ice sheet surface was below 2500 m asl. We find that our ice sheet reconstruction is in good general agreement with previous estimates of net PIS volume derived from transient modelling studies. We attribute the slightly lower aspect-ratio of our ice sheet (and its concomitant 5% reduction in volume and sea-level equivalent) to the lower yield strength applied, based on more temperate and dynamic ice sheet conditions.

Global warming-induced melting and thawing of the cryosphere are severely altering the volume and timing of water supplied from High Mountain Asia, adversely affecting downstream food and energy systems that are relied on by billions of people. The construction of more reservoirs designed to regulate streamflow and produce hydropower is a critical part of strategies for adapting to these changes. However, these projects are vulnerable to a complex set of interacting processes that are destabilizing landscapes throughout the region. Ranging in severity and the pace of change, these processes include glacial retreat and detachments, permafrost thaw and associated landslides, rock–ice avalanches, debris flows and outburst floods from glacial lakes and landslide-dammed lakes. The result is large amounts of sediment being mobilized that can fill up reservoirs, cause dam failure and degrade power turbines. Here we recommend forward-looking design and maintenance measures and sustainable sediment management solutions that can help transition towards climate change-resilient dams and reservoirs in High Mountain Asia, in large part based on improved monitoring and prediction of compound and cascading hazards.

On 7 February 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. More than 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27 × 106 cubic meters of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders greater than 20 meters in diameter and scoured the valley walls up to 220 meters above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.

Glacier recession in response to climate warming has resulted in an increase in the size and number of glacial lakes. Glacial lakes are an important focus for research as they impact water resources, glacier mass balance, and some produce catastrophic glacial lake outburst floods (GLOFs). Glaciers in Peru have retreated and thinned in recent decades, prompting the need for monitoring of ice- and water-bodies across the cordilleras. These monitoring efforts have been greatly facilitated by the availability of satellite imagery. However, knowledge gaps remain, particularly in relation to the formation, temporal evolution, and catastrophic drainage of glacial lakes. In this paper we address this gap by producing the most current and detailed glacial lake inventory in Peru and provide a set of reproducible methods that can be applied consistently for different time periods, and for other mountainous regions. The new lake inventory presented includes a total of 4557 glacial lakes covering a total area of 328.85 km2. In addition to detailing lake distribution and extent, the inventory includes other metrics, such as dam type and volume, which are important for GLOF hazard assessments. Analysis of these metrics showed that the majority of glacial lakes are detached from current glaciers (97%) and are classified as either embedded (i.e. bedrock dammed; ~64% of all lakes) or (moraine) dammed (~28% of all lakes) lakes. We also found that lake size varies with dam type; with dammed lakes tending to have larger areas than embedded lakes. The inventory presented provides an unparalleled view of the current state of glacial lakes in Peru and represents an important first step towards (1) improved understanding of glacial lakes and their topographic and morphological characteristics and (2) assessing risk associated with GLOFs.

We use examples from the European theater in World War II to argue that the assumption that combat is typically chaotic yields only limited insight into the large-scale evolution of military operations. To do this we examine the Ardennes campaigns of 1940 and 1944 in the context of explanatory devices used in physical geography such as complexity, nonlinearity, and emergence. We show that during the successful 1940 offensive that eventually led to the fall of France, the Germans were operating close to a set of thresholds in what we call the strategic space; the success of the offensive was contingent on a rapid advance and outmaneuvering of the Allied forces. In the readily defensible tactical space of the narrow Ardennes valleys, small changes in the conduct of or response to the German advance could have forced delays with profound consequences for the campaign. In 1944, by contrast, the Germans were not operating close to a system threshold and the attacking columns were frequently delayed or halted by determined resistance. Even if resistance had been weak, however, a breakout to Antwerp is unlikely to have been sustainable given the superiority in Allied power and the crippling supply problems facing the Germans.

Climate change, glacier retreat and glacial lake outburst floods (GLOFs) are intertwined. The Cordillera Blanca in Peru has one of the world's longest GLOF records and here we assess the evolution of glacial lakes in the region between 1948 and 2017 and investigate the links to documented GLOFs. We also model future lake evolution under two climate scenarios to provide an assessment of current and future GLOF triggering potential. Our analysis shows that the number of lakes as well as the total lake area has increased during the historical period. The formation of new lakes is, however, not uniform among different lake types with bedrock-dammed lakes exhibiting the largest increase in recent decades. We argue that moraine-dammed lakes have already formed at the majority of potential locations in the Cordillera Blanca and that the next generation of lakes which are expected to form in response to glacier retreat over topographically suitable areas will be predominantly bedrock-dammed. Based on a regional GLOF inventory, we show that the peak frequency of GLOFs occurred from the late 1930s to early 1950s. While GLOFs originating from moraine-dammed lakes dominated in this period, recent GLOFs have originated from bedrock-dammed lakes. At the same time, the majority of GLOFs originated from lakes in a proglacial phase (i.e. in contact with glacier), even though the share of proglacial lakes did not exceed 12% at any time step during the analysed period. While many moraine-dammed lakes evolved into the glacier-detached evolutionary phase, bedrock-dammed lakes became a major lake dam type among proglacial lakes. Over the remainder of the 21st century, a further increase in lake area of up to 10% is anticipated, with up to 50 new bedrock dammed lakes likely to develop as glaciers retreat. There is little difference in lake development and GLOF triggering potential under climate scenarios driven by RCP 2.6 and 8.5. Based on topographic disposition, recent and future lakes do not individually appear more or less susceptible to landslide impact than lakes that already developed earlier in the 20th century. Synthesizing these findings, we forecast that bedrock-dammed lakes will become the dominant source of GLOFs in the next decades. Because such dams are inherently more stable, we expect overall lower GLOF magnitudes compared to documented GLOFs from moraine-dammed lakes.

A systematic inventory of landslide events over regional spatial scales and through time is required for investigating changes in landslide frequency along-side changes in landslide triggers. This paper describes the methods used to compile a European-wide landslide inventory and some of the methodological and practical obstacles that inhibit better use and development of such inventories. We argue that these methods can be used more widely to provide a comprehensive picture of landslide populations and to further enrich our understanding of the impact of climate change and other drivers on landslide frequency and magnitude.

The high-mountain cryosphere forms water towers that are important for ecosystem services provision, supplying large populations living in mountains and the surrounding lowlands and producing potable water resources, and water for agriculture, industry and hydropower generation. However, continued glacier recession and mass loss is projected throughout the twenty-first century, and this raises major concerns regarding the future sustainability of cryospheric water resources. While glacier meltwater represents an essential drought-resilient freshwater resource in vulnerable drought-prone regions, little research has focused on the contribution made by runoff from rock glaciers. These are located widely throughout the high-mountain cryosphere and estimates of rock glacier water volume equivalent (WVEQ) vs glaciers suggests that the former may constitute increasingly important long-term water stores. Owing to the insulating effects of thick supraglacial debris cover, rock glaciers are climatically more resilient than glaciers; therefore, their relative importance versus glaciers may increase under future climate warming. Yet, while the hydrological role of debris-free glaciers and debris-covered glaciers has been the subject of much research, that of rock glaciers has received comparatively little attention. Given the need for strong climate adaptation in many of the world’s mountain regions, it is clear that a more comprehensive understanding of all components of the hydrological cycle in the high-mountain cryosphere is required.

In this thesis, I develop the scientific understanding of rock glacier significance in deglacierizing mountains across a range of spatial scales (local, national, regional and global), with a specific focus on High Mountain Asia (HMA). The review chapter critically assesses the state of current scientific knowledge regarding the hydrological role of rock glaciers in high mountain systems and serves to form the context for the empirical chapters. The thesis has three key themes to which the empirical chapters are aligned: (1) the distribution and hydrological significance of rock glaciers at global scales, (2) the distribution and hydrological significance of rock glaciers at regional and national spatial scales (Himalaya and Nepalese Himalaya), and (3) advancing rock glacier evolutionary theory.

(1) the thesis created a meta-analysis of existing systematic rock glacier inventories and compiled the first near-global rock glacier database (RGDB). The RGDB presented here includes >73,000 rock glaciers (intact = ~39,500, relict = ~33,500), which contain a WVEQ of 83.7 ± 16.7 Gt [~69–102 trillion litres]. Furthermore, the estimated ratio of rock glacier: glacier WVEQ is 1:456 globally.

(2) the results of the meta-analysis described in (1) show that only ~9% of studies included in the RGDB cover the Hindu Kush Himalaya (HKH); therefore, I produced the first systematic rock glacier inventory for the (i) Nepalese Himalaya (national-scale), and (ii) Himalaya (regional-scale). In the former (i) I inventoried >6,000 rock glaciers, and these are estimated to contain a WVEQ of 20.90 ± 4.18 km³ (19.16 ± 3.83 Gt). For the Nepalese Himalaya estimated rock glacier: glacier WVEQ ratio is 1:9. In the latter (ii) ~25,000 rock glaciers have been inventoried. The total WVEQ is 51.80 ± 10.36 km³ (47.48 ± 9.50 Gt) with an estimated rock glacier: glacier WVEQ ratio of 1:24. The results of Theme 1 and 2 indicate that rock glaciers form considerable long-term water stores, which may become increasingly important as climatically-driven glacier recession and mass loss continues throughout the twenty-first century and beyond.

(3) in order to understand debris-free glacier transition to rock glaciers I use in situ sedimentological data and kite aerial photography (KAP) data and develop a conceptual hypothesis to explain the key drivers of this process. The thesis suggests that sediment connectivity (i.e. the strength of the link between sediment sources and downslope landforms) is one such driver of these transition processes. As a consequence, I hypothesise that the presence of well-developed lateral moraines along glacier margins serves to reduce this connectivity, and thus reduce the likelihood of glacier-to-rock glacier transition occurring. The corelationships between rock glaciers and glacial, periglacial and paraglacial processes are also evaluated in the context of rock glacier origin and the changing influence these processes have upon rock glacier evolution through their lifecycle.

Collectively, this research has shaped the understanding of the current and potential future role of rock glaciers in mountain hydrology and is the first to comprehend the distribution and hydrological significance of rock glaciers globally and in the Himalaya.

We present PATICE, a GIS database of Patagonian glacial geomorphology and recalibrated chronological data. PATICE includes 58,823 landforms and 1,669 geochronological ages, and extends from 38°S to 55°S in southern South America. We use these data to generate new empirical reconstructions of the Patagonian Ice Sheet (PIS) and subsequent ice masses and ice-dammed palaeolakes at 35 ka, 30 ka, 25 ka, 20 ka, 15 ka, 13 ka (synchronous with the Antarctic Cold Reversal), 10 ka, 5 ka, 0.2 ka and 2011 AD. At 35 ka, the PIS covered of 492.6 x103 km2, had a sea level equivalent of ~1,496 mm, was 350 km wide and 2090 km long, and was grounded on the Pacific continental shelf edge. Outlet glacier lobes remained topographically confined and the largest generated the suites of subglacial streamlined bedforms characteristic of ice streams. The PIS reached its maximum extent by 33 – 28 ka from 38°S to 48°S, and earlier, around 47 ka from 48°S southwards. Net retreat from maximum positions began by 25 ka, with ice-marginal stabilisation then at 21 – 18 ka, which was then followed by rapid, irreversible deglaciation. By 15 ka, the PIS had separated into disparate ice masses, draining into large ice-dammed lakes along the eastern margin, which strongly influenced rates of recession. Glacial readvances or stabilisations occurred at least at 14 – 13 ka, 11 ka, 6 – 5 ka, 2 – 1 ka, and 0.5 – 0.2 ka. We suggest that 20th century glacial recession (% a-1) is occurring faster than at any time documented during the Holocene.

The Paris agreement aims to hold global warming to well below 2 °C and to pursue efforts to limit it to 1.5 °C relative to the pre-industrial period. Recent estimates based on population growth and intended carbon emissions from participant countries suggest global warming may exceed this ambitious target. Here we present glacier volume projections for the end of this century, under a range of high-end climate change scenarios, defined as exceeding +2° C global average warming relative to the pre-industrial period. Glacier volume is modelled by developing an elevation-dependent mass balance model for the Joint UK Land Environment Simulator (JULES). To do this, we modify JULES to include glaciated and unglaciated surfaces that can exist at multiple heights within a single grid box. Present-day mass balance is calibrated by tuning albedo, wind speed, precipitation, and temperature lapse rates to obtain the best agreement with observed mass balance profiles. JULES is forced with an ensemble of six Coupled Model Intercomparison Project Phase 5 (CMIP5) models, which were downscaled using the high-resolution HadGEM3-A atmosphere-only global climate model. The CMIP5 models use the RCP8.5 climate change scenario and were selected on the criteria of passing 2 °C global average warming during this century. The ensemble mean volume loss at the end of the century plus or minus 1 standard deviation is-64±5% for all glaciers excluding those on the peripheral of the Antarctic ice sheet. The uncertainty in the multi-model mean is rather small and caused by the sensitivity of HadGEM3-A to the boundary conditions supplied by the CMIP5 models. The regions which lose more than 75% of their initial volume by the end of the century are Alaska, western Canada and the US, Iceland, Scandinavia, the Russian Arctic, central Europe, Caucasus, high-mountain Asia, low latitudes, southern Andes, and New Zealand. The ensemble mean ice loss expressed in sea level equivalent contribution is 215.2±21.3 mm. The largest contributors to sea level rise are Alaska (44.6±1.1 mm), Arctic Canada north and south (34.9±3.0 mm), the Russian Arctic (33.3±4.8 mm), Greenland (20.1±4.4), high-mountain Asia (combined central Asia, South Asia east and west), (18.0±0.8 mm), southern Andes (14.4±0.1 mm), and Svalbard (17.0±4.6 mm). Including parametric uncertainty in the calibrated mass balance parameters gives an upper bound global volume loss of 281.1mm of sea level equivalent by the end of the century. Such large ice losses will have inevitable consequences for sea level rise and for water supply in glacier-fed river systems.

After the Last Glacial Maximum (LGM) global mean sea level (GMSL) rise was characterized by rapid increases over short (decadal to centennial) timescales superimposed on a longer term secular rise and these have been termed meltwater pulses (MWPs). In this paper we review the timing, impact and nature of these and the effects of rapid drainage of large post-glacial MWPs into the world's oceans. We identify nine MWPs, four of which occurred in three periods of rapid sea level rise (19.5–18.8, 14.8–13.0 and 11.5–11.1 ka BP). The rest are dated to the period during the Early Holocene sea level rise after 11 ka BP. We show that drainage of the known post-glacial lakes in total produced less than around 1.2 m of the 125 m of GMSLR since the LGM.

In many of the world's high mountain systems, glacier recession in response to climate change is accompanied by a paraglacial response whereby glaciers are undergoing a transition to rock glaciers. We hypothesise that this transition has important implications for hydrological resources in high mountain systems and the surrounding lowlands given the insulating effects that debris cover can have on glacier ice. Despite this, however, little is known about how this transition occurs nor how quickly, which glaciers are liable to transition, the factors driving this process and the water supply implications that follow. This paper assesses the role of glacier and rock glacier textural properties from a deglaciating region of the Himalayas to begin to address some of these issues. We investigated six landsystems on the spectrum from glaciers-to-rock glaciers in the Khumbu Himal, Nepal, and sampled for clast shape and roundness during 2016 and 2017. Kite aerial photography was additionally used to capture aerial images of an ongoing glacier-to-rock glacier transitional landform (Chola Glacier) to elucidate the surface geomorphic features of a fully transitioned landform. This image data, processed using a structure-from-motion multi-view stereo photogrammetry approach, revealed the presence of a spatially coherent ridge-and-furrow surface morphology in the lower reaches of Chola Glacier, which is potentially indicative of an ongoing glacier-to-rock glacier transition. We show that glacier-derived and slope-derived clast roundness significantly statistically different (Kolmogorov–Smirnov two-sample test: Dmax = 0.62, two-tail p <. 001; n = 1650) and suggest that sediment connectivity (i.e. linkage between sediment sources and downslope landforms) is one of the drivers of the transition process. Consequently, we hypothesise that the presence of well-developed lateral moraines along glacier margins serves to reduce this connectivity and thus the likelihood of glacier-to-rock glacier transition occurring. Understanding such processes has implications for predicting the geomorphological evolution of deglacierizing mountains under future climate warming and the water supply consequences that follow.

Rock glaciers are an important geomorphic element of glaciated mountain landscapes, but our understanding of their distribution and ages, controls on their development, and their importance in regional mountain hydrology and mountain geomorphic evolution is incomplete. In part, this incomplete knowledge arises through problems associated with identifying rock glaciers on a morphological basis alone, amplified by the multiple ways in which rock glaciers can form in different glacial, periglacial, and paraglacial settings. This study focuses on rock glaciers as a paraglacial mountain landscape element and considers the relationships between rock glaciers and glacial, periglacial, and paraglacial processes. New geomorphic and sedimentary data on different rock glaciers from the Khumbu region of Nepal are presented. These data show that even within a single region, rock glaciers may have varied origins and thus likely ages and different climatic and environmental controls. We argue that rock glaciers in deglacierizing mountains may have a long residence time in the landscape, unlike many other glacially influenced mountain landforms, and can undergo significant morphodynamic changes as glaciated landscapes transition into paraglacial landscapes.

Active rock glaciers are ice and debris-cored landforms common in cold arid mountains. They have not been widely described in the Patagonian Andes of southern South America and here we provide the first rock glacier inventory for the Jeinimeni region to the east of the contemporary North Patagonian Icefield. Detailed analysis of available satellite imagery and fieldwork demonstrates the presence of 89 rock glaciers across the study region, covering a total of 14.18 km 2. Elevation is the primary control on rock glacier distribution with 89% existing between 1600 and 1900 m.a.s.l. Aspect also plays a significant role on rock glacier formation with 80% preferentially developed on southerly slopes receiving lower solar insolation.

In this first full review of extant Quaternary Rock Slope Failure (RSF) in the British mountains, we provide a near-complete inventory of 1082 sites, 40% being rock slope deformations, 40% arrested rockslides, and 20% rock avalanches. Current RSF activity is negligible, and this relict population is predominantly paraglacial, with a parafluvial minority. Its spatial distribution is perplexing, with RSF density varying greatly, both regionally and locally. In the Scottish Highlands, eight main clusters account for 76% of RSF area in 15% of the montane area. Local concentrations occur in all the British ranges, across high and low relief, in core and peripheral locations, and on varied geological and glaciological domains; as conversely do extensive areas of sparsity, even in similar lithologies. Generic interpretations are thus precluded. Geology is only a secondary control. An association with Concentrated Erosion of Bedrock (CEB) is proposed, as a driver of intensified slope stresses. CEB is most evident at those glacial breaches of main divides where the most vigorous recent incision is inferred, and also in some trough-heads. A clear association between RSFs and these ‘late-developing’ breaches is demonstrated in the Highlands, in 42 localities, with sparsity away from them. It is also seen in seven Lake District localities. Glaciological models identify ice sheet volatility capable of driving breach ramification. High-magnitude paleoseismic events are generally unlikely to have provoked RSF clusters; a few candidates are considered. RSF has been underrated as an agent of mountain landscape evolution in Britain; its spatio-temporal incidence may assist in calibrating regional ice sheet models, and in assessing climate change impacts. We argue that the CEB:RSF association has global relevance in identifying primary drivers of mass movement in bedrock.

Glacial Lake Outburst Floods (GLOFs) have become increasingly common over the past century in response to climate change, posing risks for human activities in many mountain regions. In this paper we document and reconstruct the sequence of events and impact of a large GLOF that took place in December 2015 in the Chileno Valley, Patagonia. Hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105.6 × 10 6 m 3 of water. The sequence of events was as follows: (1) a large debris flow entered the lake from two steep and largely non-vegetated mountain gullies located northeast of the Chileno Glacier terminus. (2) Water displaced in the lake by the debris flow increased the discharge through the Chileno Lake outflow. (3) Lake and moraine sediments were eroded by the flood. (4) Eroded sediments were redistributed downstream by the GLOF. The post-GLOF channel at the lake outlet widened in some places by >130 m and the surface elevation of the terrain lowered by a maximum of 38.8 ± 1.5 m. Farther downstream, large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an ~340 m wide fan with an average increase in surface elevation over the pre-GLOF surface of 4.6 ± 1.5 m. We estimate that around 3.5 million m 3 of material was eroded from the flood-affected area whilst over 0.5 million m 3 of material was deposited in the downstream GLOF fan. The large debris flow that triggered the GLOF was probably a paraglacial response to glacier recession from its Little Ice Age limits. We suggest that GLOFs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes. Detailed studies of GLOF events are currently limited in Patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region.

An archaeological survey of well-preserved Second World War German supply depots and bomb craters from Allied air raids in the Forêt domaniale des Andaines, Normandy, has prompted an evaluation of the effectiveness of Allied intelligence gathering and tactical bombing of the German logistics network in advance of, and during the Normandy Campaign of June–August 1944. In conjunction with analysis of primary German and Allied archive sources, published historical accounts and aerial photographs, we demonstrate that Allied intelligence knew of the importance of the forest as a major fuel depot and attacked it with at least 46 missions over the period 13 June–4 August. However, landscape evidence demonstrates that only one of three fuel depot sites in the forest was successfully identified and partially destroyed by bombing. Allied intelligence efforts also failed to gather sufficient evidence to target one of the largest Seventh Army munitions depots in Normandy. Supply depots in the forest thus remained operational until late in the campaign and will have supported the German Mortain counter-offensive of 7–14 August. The limited success of Allied bombing in the Forêt domaniale des Andaines testifies to the difficulties in striking well-dispersed and camouflaged woodland facilities and supports the argument that the success of air power against German logistics efforts lay primarily in the degradation of the regional communications infrastructure and the Wehrmacht’s vehicle fleet rather than the destruction of supply dumps.

Recent climate change has had a major impact on biodiversity and has altered the geographical distribution of vascular plant species. This trend is visible globally; however, more local and regional scale research is needed to improve understanding of the patterns of change and to develop appropriate conservation strategies that can minimise cultural, health, and economic losses at finer scales. Here we describe a method to manually geo-reference botanical records from a historical herbarium to track changes in the geographical distributions of plant species in West Cornwall (South West England) using both historical (pre-1900) and contemporary (post-1900) distribution records. We also assess the use of Ellenberg and climate indicator values as markers of responses to climate and environmental change. Using these techniques we detect a loss in 19 plant species, with 6 species losing more than 50% of their previous range. Statistical analysis showed that Ellenberg (light, moisture, nitrogen) and climate indicator values (mean January temperature, mean July temperature and mean precipitation) could be used as environmental change indicators. Significantly higher percentages of area lost were detected in species with lower January temperatures, July temperatures, light, and nitrogen values, as well as higher annual precipitation and moisture values. This study highlights the importance of historical records in examining the changes in plant species' geographical distributions. We present a method for manual geo-referencing of such records, and demonstrate how using Ellenberg and climate indicator values as environmental and climate change indicators can contribute towards directing appropriate conservation strategies.

Glacier recession driven by climate change produces glacial lakes, some of which are hazardous. Our study assesses the evolution of three of the most hazardous moraine-dammed proglacial lakes in the Nepal Himalaya-Imja, Lower Barun, and Thulagi. Imja Lake (up to 150 m deep; 78.4 × 106 m3 volume; surveyed in October 2014) and Lower Barun Lake (205 m maximum observed depth; 112.3 × 106 m3 volume; surveyed in October 2015) are much deeper than previously measured, and their readily drainable volumes are slowly growing. Their surface areas have been increasing at an accelerating pace from a few small supraglacial lakes in the 1950s/1960s to 1.33 km2 and 1.79 km2 in 2017, respectively. In contrast, the surface area (0.89 km2) and volume of Thulagi lake (76 m maximum observed depth; 36.1 × 106 m3; surveyed in October 2017) has remained almost stable for about two decades. Analyses of changes in the moraine dams of the three lakes using digital elevation models (DEMs) quantifies the degradation of the dams due to the melting of their ice cores and hence their natural lowering rates as well as the potential for glacial lake outburst floods (GLOFs). We examined the likely future evolution of lake growth and hazard processes associated with lake instability, which suggests faster growth and increased hazard potential at Lower Barun lake.

© 2018 the Authors the prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

The environmental, socioeconomic and cultural significance of glaciers has motivated several countries to regulate activities on glaciers and glacierized surroundings. However, laws written to specifically protect mountain glaciers have only recently been considered within national political agendas. Glacier Protection Laws (GPLs) originate in countries where mining has damaged glaciers and have been adopted with the aim of protecting the cryosphere from harmful activities. Here, we analyze GPLs in Argentina (approved) and Chile (under discussion) to identify potential environmental conflicts arising from law restrictions and omissions. We conclude that GPLs overlook the dynamics of glaciers and could prevent or delay actions needed to mitigate glacial hazards (e.g. artificial drainage of glacial lakes) thus placing populations at risk. Furthermore, GPL restrictions could hinder strategies (e.g. use of glacial lakes as reservoirs) to mitigate adverse impacts of climate change. Arguably, more flexible GPLs are needed to protect us from the changing cryosphere.

Abstract. The Paris agreement aims to hold global warming to well below 2 °C and to pursue efforts to limit it to 1.5 °C relative to the pre-industrial period. Recent estimates based on population growth and intended carbon emissions from participant countries, suggest global warming may exceed this ambitious target. Here we present glacier volume projections for the end of this century, under a range of high-end climate change scenarios, defined as exceeding +2 °C global average warming relative to the preindustrial period. Glacier volume is modelled by developing an elevation-dependent mass balance model for the Joint UK Land Environmental Simulator (JULES). To do this, we modify JULES to include glaciated and un-glaciated surfaces that can exist at multiple heights within a single grid-box. Present day mass balance is calibrated by tuning albedo, wind speed, precipitation and temperature lapse rates to obtain the best agreement with observed mass balance profiles. JULES is forced with an ensemble of six Coupled Model Intercomparison Project Phase 5 (CMIP5) models which were downscaled using the high resolution HadGEM3-A atmosphere only global climate model. The ensemble mean volume loss at the end of the century plus/minus one standard deviation is, minus;64 ± 5 % for all glaciers excluding those on the peripheral of the Antarctic ice sheet. The uncertainty in the multi-model mean is rather small and caused by the sensitivity of HadGEM3-A to the boundary conditions supplied by the CMIP5 models. The regions which lose more than 75% of their initial volume by the end of the century are; Alaska, Western Canada and US, Iceland, Scandinavia, Russian Arctic, Central Europe, Caucasus, High Mountain Asia, Low Latitudes, Southern Andes and New Zealand. The ensemble mean ice loss expressed in sea-level equivalent contribution is 215.2 ± 21.3 mm. The largest contributors to sea level rise are Alaska (44.6 ± 1.1 mm), Arctic Canada North and South (34.9 ± 3.0 mm), Russian Arctic (33.3 ± 4.8 mm), Greenland (20.1 ± 4.4), High Mountain Asia (combined Central Asia, South Asia East and West), (18.0 ± 0.8 mm), Southern Andes (14.4 ± 0.1 mm) and Svalbard (17.0 ± 4.6 mm). Including parametric uncertainty in the calibrated mass balance parameters, gives an upper bound global volume loss of 247.3 mm, sea-level equivalent by the end of the century. Such large ice losses will have inevitable consequences for sea-level rise and for water supply in glacier-fed river systems.
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Paraglacial processes represent the dominant mechanism of geomorphic change in deglaciating landscapes worldwide and are now being increasingly recognised as controls on deglacial and postglacial landscape dynamics. This reflects the influence of glacigenic lithospheric loading/unloading cycles and patterns of glacigenic erosion and deposition. Ireland is an important location for studying the impacts of paraglacial processes in the landscape, as it was strongly imprinted by the erosional and depositional imprints of late Pleistocene glaciations and was affected by rapid shifts in North Atlantic climate. Using examples from mountains, rivers and coasts from across Ireland, this study examines some of the varied landscape responses to paraglacial relaxation in these different settings. The purpose behind this study is to show how the styles of paraglacial response may vary over time and space, even within a single regional landscape, and this can help assess the sensitivity of different environments affected by paraglacial relaxation. This study proposes an evolutionary model that describes the paraglacial sediment cascade that has shaped the Irish landscape during the lateglacial and Holocene. Consideration of paraglacial processes can yield a better understanding of the postglacial evolution of mountain, river and coastal landscapes in Ireland.

Two main ways in which the progress of deglaciation in mountains can be identified and monitored are through (a) meltwater loss over time as glaciers and permafrost melt and (b) enhanced sediment yield over time as loose sediments are released downslope. Conceptually, both these outcomes of glacier retreat can be considered through their relationship to models of paraglacial landscape evolution, which describe how volume fluxes of meltwater and sediments change over time in mountains that are becoming deglacierized, and the different landforms that exist during different stages of landscape evolution. This paper critically reconsiders paraglacial landscape evolution models with respect to the separate timings and magnitudes of meltwater and sediment fluxes, drawing from examples from past and present deglacierizing mountains worldwide. This analysis shows that constructions of paraglacial systems simply as sediment cascades cannot be uncritically supported and that paraglacial systems can be best considered as reflecting transient stages of evolution in which meltwater and sediment fluxes vary over time and space. These transient properties of paraglacial systems have important implications for the ways in which the dynamics of these systems are conceptualized and modelled, with respect to the paraglacial evolution of mountain landscapes and mountain geohazards, especially under conditions of global warming and glacier recession.

Abstract. Despite recent research identifying a clear anthropogenic impact on glacier recession, the effect of recent climate change on glacier-related hazards is at present unclear. Here we present the first global spatio-temporal assessment of glacial lake outburst floods (GLOFs) focusing explicitly on lake drainage following moraine dam failure. These floods occur as mountain glaciers recede and downwaste and many have an enormous impact on downstream communities and infrastructure. Our assessment of GLOFs associated with the collapse of moraine-dammed lakes provides insights into the historical trends of GLOFs and their distributions under current and future global climate change. We observe a clear global increase in GLOF frequency and their regularity around 1930, which likely represents a lagged response to post-Little Ice Age warming. Notably, we also show that GLOF frequency and their regularity – rather unexpectedly – has declined in recent decades even during a time of rapid glacier recession. Although previous studies have suggested that GLOFs will increase in response to climate warming and glacier recession, our global results demonstrate that this has not yet clearly happened. From assessment of the timing of climate forcing, lag times in glacier recession, lake formation and moraine dam failure, we predict increased GLOF frequencies during the next decades and into the 22nd century.
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The periglacial realm is a major part of the cryosphere, covering a quarter of Earth's land surface. Cryogenic land surface processes (LSPs) control landscape development, ecosystem functioning and climate through biogeochemical feedbacks, but their response to contemporary climate change is unclear. Here, by statistically modelling the current and future distributions of four major LSPs unique to periglacial regions at fine scale, we show fundamental changes in the periglacial climate realm are inevitable with future climate change. Even with the most optimistic CO2 emissions scenario (Representative Concentration Pathway (RCP) 2.6) we predict a 72% reduction in the current periglacial climate realm by 2050 in our climatically sensitive northern Europe study area. These impacts are projected to be especially severe in high-latitude continental interiors. We further predict that by the end of the twenty-first century active periglacial LSPs will exist only at high elevations. These results forecast a future tipping point in the operation of cold-region LSP, and predict fundamental landscape-level modifications in ground conditions and related atmospheric feedbacks.Cryogenic land surface processes characterise the periglacial realm and control landscape development and ecosystem functioning. Here, via statistical modelling, the authors predict a 72% reduction of the periglacial realm in Northern Europe by 2050, and almost complete disappearance by 2100.

Water resources in many of the world’s arid mountain ranges are threatened by climate change, and in parts of the South American Andes this is exacerbated by glacier recession and population growth. Alternative sources of water, such as more resilient permafrost features (e.g. rock glaciers), are expected to become increasingly important as current warming continues. Assessments of current and future permafrost extent under climate change are not available for the Southern Hemisphere, yet are required to inform decision making over future water supply and climate change adaptation strategies. Here, downscaled model outputs were used to calculate the projected changes in permafrost extent for a first-order assessment of an example region, the Bolivian Andes. Using the 0 °C mean annual air temperature as a proxy for permafrost extent, these projections show that permafrost areas will shrink from present day extent by up to 95 % under warming projected for the 2050s and by 99 % for the 2080s (under the IPCC A1B scenario, given equilibrium conditions). Using active rock glaciers as a proxy for the lower limit of permafrost extent, we also estimate that projected temperature changes would drive a near total loss of currently active rock glaciers in this region by the end of the century. In conjunction with glacier recession, a loss of permafrost extent of this magnitude represents a water security problem for the latter part of the 21st century, and it is likely that this will have negative effects on one of South America’s fastest growing cities (La Paz), with similar implications for other arid mountain regions.

Supraglacial debris cover is an important component of glacier mass balance, especially in areas characterised by widespread glacier recession. Mapping of the spatial and temporal changes in debris cover on the surface of the receding outlet glaciers of the temperate North Patagonian Icefield (NPI) in southern South America between 1987 and 2015 shows that the total amount of debris cover has increased over time, from 168 km2 in 1987 to 307 km2 in 2015. The number of debris-covered glaciers increased from 24 in 1987, to 31 in 2001 and 32 out of 43 studied glaciers in 2015. The proportion of debris-covered area has also increased, from 4.1% in 1987 to 7.9% in 2015, with the largest proportional increases occurring east of the ice divide (where 15.2% of the glacier ice is now debris covered). Over this time, the total area of the NPI decreased from 4133 to 3887 km2. The area occupied by proglacial and ice-proximal lakes also increased from 112 to 198 km2. Between 1987 and 2015, the terminal environment of many of the outlet glaciers of the NPI changed from land-terminating to lake-calving, and these glaciers are now receding into terminal lakes. The change in the area of debris-covered ice is influenced by the loss of ice at debris-covered termini and by an increase in debris cover at higher elevations. The glaciers of the NPI remain highly dynamic as they recede and are therefore behaving very differently to high-elevation glaciers, such as those of the Himalaya, where debris cover leads to glacier stagnation at the termini.

Landslides present a geomorphological hazard in Alpine regions, threatening life, infrastructure and property. Here we present the development of a new regional landslide inventory (RI) for the European Alps. This database provides a substantial temporal and spatial picture of landsliding in the Alps, with particular focus on the Swiss and French Alps. We use segmented models to evaluate recording bias in the temporal record. We use scaling relationships to calculate landslide area based on a given volume for similar types of landslide; with the result of this being that 9.5% of the landslides recorded in the RI now have area data recorded. These landslide area data are then used to examine the log-linear trend, which exists between landslide area and frequency in inventories. We show that this relationship is present for this historical dataset; however, none of the individual databases, nor a unification of these, contain a complete record with the small and larger landslides being recorded more consistently. The use of segmented models on the temporal distribution of landslides in the RI shows that the post-1970 portion of the database is more reliable, highlighted through an improved power-law relationship, although the frequency of medium sized landslides is still underestimated. We show that creating a unified database (RI) can increase the reliability of datasets and consistency in recording for the use by researchers for attribution and detection studies.

This study tracks local vegetation change in West Cornwall (South West England) within regional context, using historic herbarium (pre-1900) and recent vegetation records (post-1900). The focus centres on species lost from the region over the past century. For this study we used a collection of herbarium records published in 1909 (Davey's "Flora of Cornwall") and contemporary records from the "New Atlas of British and Irish Flora" downloaded from the National Biodiversity Network (NBN), online database. Both data sets were spatially analysed using ArcGIS in order to detect local scale species loss. Our results showed that species loss was highest in the south (11 plant species), compared to the loss from middle areas (6 plant species) and in the northern area (8 plant species) of West Cornwall. Results on species change at the local scale were different to the changes that are happening at the national scale. Loss from West Cornwall was detected for two plant species, Mountain Melick (. Melica nutans) and Field Eryngo (. Eryngium campestare). These key results amplify the importance of local scale research and conservation in order to protect ecosystems functioning, genetic diversity, ecosystem services and regional identity.

Water scarcity is a growing issue for high altitude arid countries like Bolivia, where serious water resource concerns exist because of climate change and population growth. In this study we use a recent Bolivian rock glacier inventory (Rangecroft et al. 2014) to estimate the water equivalent storage of these understudied cryospheric reserves. This paper shows that Bolivian rock glaciers currently store between 11.7 and 137 million cubic meters of water. Rock glacier water equivalents are compared to corresponding ice glacier water equivalent to allow an assessment of the hydrological importance of rock glaciers as water stores in this water scarce region. It can be seen that in the densely glaciated Cordillera Real (15°-16°S) rock glaciers form a small component of mountain water stores; however, along the Cordillera Occidental (17°-22°S), where ice glaciers are absent, rock glaciers are a more important part of the cryospheric water store, suggesting that they could be important for local water management. This is the first time that the water equivalence of the Bolivian rock glacier store has been quantified and is a first step toward assessing the contribution and importance of alternative high altitude water sources.

Until recently, the scientific consensus has been that the uplands of south-west Britain remained unglaciated throughout the Quaternary, with glacial ice sheet limits lying to the north of the south-west peninsula. However, recent work has shown that small glaciers and ice caps existed in the uplands of Exmoor and Dartmoor during the late Quaternary, demonstrating that the consensus of an unglaciated south-west Britain requires considerable revision. Here we report geomorphological and sedimentary evidence supported by glacier-climate modelling for a Quaternary niche glacier from west Cornwall, south-west England. This niche glacier represents the southernmost such system from mainland Great Britain, and provides evidence for the presence of extra-glacial niche glaciers probably during the Last Glacial Maximum of the Devensian glaciation, and well outside the limits of the main British-Irish Ice Sheet.

Rock glaciers in the arid Bolivian Andes are potentially important water sources, but little is known about their spatial distribution and characteristics. We provide the first rock glacier inventory for the region (15-22°S), based on mapping using remote sensing data in Google Earth, supported by field validation. of the 94 rock glaciers identified, 57 per cent were classified as active (containing ice) and the remaining as relict (not containing ice). The majority (87%) have a southerly aspect (SE, S and SW), and the rock glacier length and area averages were 500m and 0.12km2, respectively. We approximate the lower limit of permafrost to be at 4700m in the Bolivian Andes, with the mean minimum altitude of rock glacier fronts estimated to be 4980m for active rock glaciers, and about 100m lower for relict rock glaciers. The inventory provides an important first step towards assessing the spatial distribution of regional permafrost as well as information to allow permafrost-based water resources in the Bolivian Andes to be understood against a backdrop of severe glacier recession. Copyright

In this study we used the Schmidt hammer to assess the relative exposure ages of previously dated Little Ice Age moraines deposited by Svellnosbreen glacier in Jotunheimen southern Norway. Schmidt hammer measurements were taken on moraine surfaces which have been deglaciated for 79-259 years since the Little Ice Age, to reconstruct and date previous snout positions. Dating used a typical linear Little Ice Age age-calibration curve and the ages of unknown surfaces were predicted based on Schmidt hammer measurements with the support of lichenometric dates. Calibrated ages exhibited potential dating errors of ±63-103 years, which were estimated using 95% confidence intervals associated with two control points based on moraines of known ages. Schmidt hammer R-value variability was identified and sources of significant errors were attributed to variations in boulder surface texture and the incorporation of weathered boulders into moraines through push mechanisms and paraglacial reworking. © 2014 Swedish Society for Anthropology and Geography.

For many decades, studies in physical geography, geomorphology, sedimentology and stratigraphy have used uniformitarianism as a guiding principle by which to interpret environmental and land surface changes over different spatial and temporal scales. In this paper we argue that, as the Anthropocene proceeds and Earth systems increasingly move away from the mix of geomorphological processes typical of interglacial periods, significant limitations arise regarding the use of uniformitarianism as a principle by which to interpret Earth surface systems of the present and future. We argue that looking to changes in linked climate and land-surface processes of past interglacial periods is increasingly inappropriate in evaluating the impacts of ongoing climate change on Earth surface processes of the Anthropocene in which complex human-induced land surface feedbacks are increasingly important. We argue that all geoscientists need to critically reconsider whether the long-held assumptions of uniformitarianism are useful in the Anthropocene era.

It is widely believed that the last glaciers in the British Isles disappeared at the end of the Younger Dryas stadial (12.9-11.7 cal. kyr BP). Here, we use a glacier-climate model driven by data from local weather stations to show for the first time that glaciers developed during the Little Ice Age (LIA) in the Cairngorm Mountains. Our model is forced from contemporary conditions by a realistic difference in mean annual air temperature of -1.5°C and an increase in annual precipitation of 10%, and confirmed by sensitivity analyses. These results are supported by the presence of small boulder moraines well within Younger Dryas ice limits, and by a dating programme on a moraine in one cirque. As a result, we argue that the last glaciers in the Cairngorm Mountains (and perhaps elsewhere in upland Britain) existed in the LIA within the last few hundred years, rather than during the Younger Dryas. © the Author(s) 2013.

Globally, glacial and paraglacial environments in mountains are vulnerable to the effects of ongoing contemporary climate change (global warming), but monitoring of such systems today provides only a limited spatial and temporal viewpoint of their likely evolution over coming decades to centuries. This is because these environments show complex and nonlinear responses to forcing and are affected by time lags, feedbacks and antecedent factors, including geologic control and geologic history that present monitoring of these systems cannot capture. In order to evaluate how glacial and paraglacial environments in mountains are likely to respond to future climate change, we consider how these environments have responded to climate change in the past (the last glacial-interglacial transition, and the Little Ice Age). From this, we may anticipate the likely responses of glacial and paraglacial environments in mountains to global warming over coming decades. We show that future changes in glacial and paraglacial environments, in particular in glaciated regions in continental interiors, have downstream implications for the biosphere (including biodiversity and ecosystem services, sustainable agriculture and water resources), the human environment (including cultural and heritage landscapes and social/economic activities), and for policy and planning. These will be important issues for the later twenty-first century and beyond. © 2014 Swedish Society for Anthropology and Geography.

West Cornwall is the most south westerly part of mainland United Kingdom with a strong maritime climate. This paper analyses the earliest archived instrumental meteorological records collected in West Cornwall (SW England). Observations were obtained from the Met Office archive (Camborne 1957-2010; Culdrose 1985-2011), Trengwainton Garden (1940-2010), and from the Royal Cornwall Polytechnic Society, (data for Falmouth (1880-1952) and Helston (1843-1888)). Homogeneity tests were used (Levene and Brown-Forsythe tests) to exclude any trends not related to climate variability. The data exhibit trends in annual mean and maximum temperatures over the timescales analysed, and show a general temperature increase in the 20th and 21st century. Annual and seasonal temperature change was found to vary locally with strongly positive trends in autumn, spring and summer seasons. Trends in precipitation are positive only for the 19th century and only for one station. Correlation with the North Atlantic Oscillation (NAO) index gives negative results for precipitation data. However correlation with the NAO index is positive with temperature, especially in the winter season. Return period analysis shows a decrease in intensity and frequency of extreme precipitation events in the post-1975 period (Camborne and Trengwainton Garden stations). Climate change in the 20th century and future continued warming is likely to have major implications on biodiversity in this region. © 2014 Springer Science+Business Media Dordrecht.

Relationships between landscape-scale geomorphology and aspects of the human environment (including heritage and material cultures) are best examined in landscapes with a strong geomorphological imprint of past climatic and environmental changes, and where human activity has been present for a long period of time. In Cornwall, southwest England, a strong geomorphological signature is imparted by weathering of granite bedrock under cold Quaternary climates, and a strong cultural and heritage imprint is manifested in material and nonmaterial ways through archaeology, art, literature and folklore, and is illustrated in this paper through examples of Bodmin Moor (north Cornwall) and West Penwith (west Cornwall). Landscapes of Bodmin Moor include wide valleys with underfit rivers and upland summits with prominent tors, resulting from granite weathering and slope processes during the Tertiary and Quaternary. Pollen records show how human activity has changed on the moor over time, with a peak of settlement during the Bronze Age, and expansion of grazing into the Iron Age. Daphne du Maurier's novels, set on or adjacent to Bodmin Moor, emphasize the moor's relationship to unstable and intense human emotions and crises. In West Penwith, which is geomorphological similar to Bodmin Moor, geomorphology-culture relations are demonstrated in different ways but through a similar sense of place and regional identity. The St Ives School of early 20th Century art, including the local artist Peter Lanyon and the sculptor Barbara Hepworth, draws inspiration from the local land and seascapes. The oral traditions and folklore of Zennor emphasize the importance of witchcraft and superstition that are in part founded on the wildness of upland summits and stormy coastline. Across West Penwith, tin mining and the mining trade exerted a strong impact on regional socioeconomic and cultural development from the Bronze Age until the end of the 19th Century, seen through settlement patterns, scientific innovation and Nonconformism. Today these geomorphology-culture relations are memorialized in the Cornwall and West Devon Mining Landscape World Heritage Site. © 2013 Elsevier Ltd.

The existence of a small population of 'relict rock glaciers' scattered across the main British mountain areas has previously been inferred from published cases of individual sites or local clusters. Discrete debris accumulations (DDAs) of widely differing character have been identified as ice-debris landforms (whether 'rock glaciers' or 'protalus lobes') partly from morphological, sedimentological and topo-locational evidence, but principally by analogy with both active and relict examples in present-day arctic/alpine environments, with consequent palaeoclimate inferences. However, re-interpretation of several supposed rock glaciers as rock slope failures has cast doubt on both the palaeoclimatic reconstructions and the origin of the remaining features. Issues of polygenesis and mimicry/equifinality have contributed to some previous misidentifications. We re-evaluate the 28 candidate cases based on new field and image-analysis evidence and place them on a continuum from no ice presence through passive ice presence and glacial shaping to emplacement onto glacier ice with consequent melt-out topography. A null hypothesis approach (that there are no relict rock glaciers in the British mountains) is pursued, and the evidence indicates that none of the 28 cases clearly warrants classification as a relict rock glacier; their characteristics can be explained without recourse to any significant forward debris movement controlled or facilitated by incorporated or underlying ice as it deforms and melts out. However, only one-third of the candidate DDAs are attributed in whole or part to rock slope failure (sensu stricto), with other debris sources including incremental rockfall, bedrock knolls with coarse debris veneer, protalus rampart and moraine. A few cases deserve more detailed investigation of their structure, morphology and sediments within a broader local glaciological/topographical context, with multitemporal/polygenetic evolution in mind. But it is for future researchers to demonstrate that deforming ice played an incontestable part in shaping these often enigmatic DDAs, given that other causes are simpler and commoner. © 2013 John Wiley & Sons, Ltd.

Climate change is projected to have a strongly negative effect on water supplies in the arid mountains of South America, significantly impacting millions of people. As one of the poorest countries in the region, Bolivia is particularly vulnerable to such changes due to its limited capacity to adapt. Water security is threatened further by glacial recession with Bolivian glaciers losing nearly half their ice mass over the past 50 years raising serious water management concerns. This review examines current trends in water availability and glacier melt in the Bolivian Andes, assesses the driving factors of reduced water availability and identifies key gaps in our knowledge of the Andean cryosphere. The lack of research regarding permafrost water sources in the Bolivian Andes is addressed, with focus on the potential contribution to mountain water supplies provided by rock glaciers.

Here we present the first reconstruction of vertical ice-sheet profile changes from any of the Southern Hemisphere's mid-latitude Pleistocene ice sheets. We use cosmogenic radio-nuclide (CRN) exposure analysis to record the decay of the former Patagonian Ice Sheet (PIS) from the Last Glacial Maximum (LGM) and into the late glacial. Our samples, from mountains along an east-west transect to the east of the present North Patagonian Icefield (NPI), serve as 'dipsticks' that allow us to reconstruct past changes in ice-sheet thickness, and demonstrates that the former PIS remained extensive and close to its LGM extent in this region until ~19.0 ka. After this time rapid ice-sheet thinning, initiated at ~18.1 ka, saw ice at or near its present dimension by 15.5 ka. We argue this rapid thinning was triggered by a combination of the rapid southward migration of the precipitation bearing Southern Hemisphere (SH) westerlies and regional warming.

Submarine mass failures (which include submarine slides or submarine landslides) occur widely on open continental margins. Understanding their cause is of great importance in view of the danger that they can pose both to coastal populations through tsunamis and to the exploitation of ocean floor resources through mass movement of the sea floor. Present knowledge of the causes of submarine mass failures is briefly reviewed, focussing on the role of sea level rise, a process which has previously only infrequently been cited as a cause. It is argued that sea level rise could easily have been involved in at least some of these events by contributing to increased overpressure in sediments of the continental margin whilst causing seismic activity. The Holocene Storegga Slide off South West Norway may have been partly caused by the early Holocene sea level rise in the area, accentuated by meltwater flux from the discharges of Lake Agassiz-Ojibway in North America. Relative sea level rise increased water loading on the Norwegian continental margin, increasing overpressure in the sediments and also causing seismic activity, triggering the Holocene Storegga Slide. Given that some forecasts of future sea level rise are not greatly different from rises which obtained during the early Holocene, the implications of rising sea levels for submarine mass failures in a global warming world are considered. © 2013 Elsevier Ltd.

National and international policy initiatives have focused on reducing carbon emissions as a means by which to limit future climate warming. Much less attention has been paid by policymakers to monitoring, modelling and managing the impacts of climate change on the dynamics of Earth surface systems, including glaciers, rivers, mountains and coasts. This is a critical omission, however, as Earth surface systems provide water and soil resources, sustain ecosystem services and strongly influence biogeochemical climate feedbacks in ways that are as yet uncertain. We argue that there is a significant policy gap regarding the management of Earth surface systems' impacts under climate change that needs to be closed to facilitate the sustainability of cross-national Earth surface resource use. It is also a significant challenge to the scientific community to better understand Earth surface systems' sensitivity to climate forcing. © 2013 Macmillan Publishers Limited. All rights reserved.

Traditionally regarded as a relict permafrost and periglacial landscape that lay beyond the limits of Pleistocene glaciation, the granite uplands of northern Dartmoor in south-west England in fact contain geomorphological evidence for the former existence of a plateau ice cap, making the area the location of the southernmost independent glacier mass in the British Isles. In addition to weakly U-shaped valleys, the most prominent evidence comprises arcuate and linear bouldery ridges and hummocky valley floor drift, which are interpreted as latero-frontal moraines deposited by the outlet glacier lobes of a plateau ice cap. Inset sequences of these depositional landforms, in association with meltwater channels, demarcate the receding margins of the glacier lobes. A numerical model of ice cap development shows that a predominantly thin plateau icefield type glaciation is required in order to produce significant ice flow into surrounding valleys. The highest and most extensive plateau areas were occupied by ice for the longest cumulative period of time throughout the Pleistocene, thereby explaining: (1) the lack of tors in such areas as the product of 'average' glacial conditions preferentially removing tors or dampening their production rates, (2) the survival of high relief tors during glaciation if they occupied summits too narrow to develop thick and erosive glacier ice, and (3) the survival of subdued tors in areas glaciated less regularly during the Pleistocene. © 2012 Blackwell Publishing Ltd, the Geologists' Association & the Geological Society of London.

Lately, glaciers have been subjects of unceasing controversy. Current debate about planned hydroelectric facilitiesa US$7- to $10-billion megaprojectin a pristine glacierized area of Patagonia, Chile [Romero Toledo et al. 2009; Vince, 2010], has raised anew the matter of how glaciologists and global change experts can contribute their knowledge to civic debates on important issues. There has been greater respect for science in this controversy than in some previous debates over projects that pertain to glaciers, although valid economic motivations again could trump science and drive a solution to the energy supply problem before the associated safety and environmental problems are understood. The connection between glaciers and climate changeboth anthropogenic and naturalis fundamental to glaciology and to glaciers' practical importance for water and hydropower resources, agriculture, tourism, mining, natural hazards, ecosystem conservation, and sea level [Buytaert et al. 2010; Glasser et al. 2011]. The conflict between conservation and development can be sharper in glacierized regions than almost anywhere else. Glaciers occur in spectacular natural landscapes, but they also supply prodigious exploitable meltwater. © 2012. American Geophysical Union. All Rights Reserved.

The granite uplands of Dartmoor have traditionally been considered to be relict permafrost and periglacial landscapes that lay beyond the limits of Quaternary glaciations but a variety of landform evidence indicates that a plateau icefield existed on the northern part of the moor, constituting the southernmost independent ice cap in the British Isles. Overdeepened or weakly U-shaped valley segments fringing north Dartmoor document an early, extensive phase of glaciation but the most convincing landform evidence relates to more recent, valley-based glacier occupancy. A moraine ridge on the Slipper Stones represents the most unequivocal palaeo-glacier on north Dartmoor with a palaeo-ELA of c.460 m above sea level (asl), although this relates to the youngest and most restricted phase of glaciation. A longer term ELA is likely to be represented by the Corn Ridge proto-cirque at 370-410 m asl. More extensive valley glaciers are recorded in each of the major drainage basins of north Dartmoor by arcuate and linear bouldery ridges and hummocky valley floor drift, which are interpreted as latero-frontal moraines deposited by outlet lobes of a plateau icefield. Recession of these lobes is marked by inset sequences of such ridges and occasional meltwater channels. Plateau ice was predominantly thin and protective, and snowblow and preferential accumulation in valley heads facilitated the modest glacial erosion and debris transport recorded in the landforms and sediments. It is proposed that the highest plateaux have been occupied by ice for the longest cumulative period of time throughout the Quaternary (" average glacial conditions" ), explaining the distribution of different tor types on northern Dartmoor. This also explains the lack of tors on the most expansive of the highest plateau terrain (ice dispersal centres) as the product of: a) average glacial conditions preferentially removing tors or dampening their production rates; b) the survival of high relief (Type 1) tors during glaciation if they occupy summits too narrow to develop significant plateau icefields and/or ridges that are bypassed by faster moving ice in adjacent deep valleys; and c) the survival of subdued (Type 2) tors in areas glaciated less regularly during the Quaternary. Simple ice flow modelling indicates that a plateau icefield type glaciation is required for significant ice flow to occur and confirms thin ice cover, in particular on narrow summits, thereby supporting the explanation of tor class distribution. The modelling allows us to spatially correlate the geomorphological evidence of margin positions into two major stages and further indicates a strong altitude-mass balance feedback leading to an ice cap that is not in balance with its climate and with an extent that is limited by the length of the cold phases rather than their severity. © 2012 Elsevier Ltd.

Reliable dating of Southern Hemisphere glacier fluctuations since the Last Glacial Maximum (LGM) is crucial to resolving debates about millennial-scale climate change. Here we present 10Be dates for lateral, valley-mouth and cross-valley moraines formed between the contemporary South American North Patagonian Icefield (NPI) and its LGM position in four separate valleys around 47°S. This is an area near the core of the precipitation-bearing southern westerly winds, where it is known that rapid shifts in climate occurred during Lateglacial times. The dates indicate that outlet glaciers advanced, or at least stabilised, to form large moraines east of an expanded NPI at 11.0 ± 0.5/11.2 ± 0.6, 11.5 ± 0.6, 11.7 ± 0.6 and 12.8 ± 0.7 ka (Putnam southern-hemisphere production rates and Dunai scaling scheme, assumed boulder erosion rate of 2 mm/ka). Four of these ages are statistically indistinguishable and probably represent a single, regional ice advance. The dates indicate that glaciers in Patagonia were larger during these times than at any point since the LGM and provide evidence in Patagonia for glacier advances around the time of the European Younger Dryas (12.9-11.7 ka) and into the very early Holocene. Although palaeoclimatic records from this area are often contradictory, these glacier advances were probably associated with a period of cooling or regionally increased precipitation related to the changes in the position of the southern westerly winds. © 2012 Elsevier Ltd.

The melting of mountain glaciers and ice caps is expected to contribute significantly to sea-level rise in the twenty-first century although the magnitude of this contribution is not fully constrained. Glaciers in the Patagonian Icefields of South America are thought to have contributed about 10% of the total sea-level rise attributable to mountain glaciers in the past 50 years. However, it is unclear whether recent rates of glacier recession in Patagonia are unusual relative to the past few centuries. Here we reconstruct the recession of these glaciers using remote sensing and field determinations of trimline and terminal moraine location. We estimate that the North Patagonian Icefield has lost 103±20.7 km3 of ice since its late Holocene peak extent in AD 1870 and that the South Patagonian Icefield has lost 503±101.1 km3 since its peak in AD 1650. This equates to a sea-level contribution of 0.0018±0.0004 mm yr−1 since 1870 from the north and 0.0034±0.0007 mm yr−1 since 1650 from the south. The centennial rates of sea-level contribution we derive are one order of magnitude lower than estimates of melting over the past 50 years3, even when we account for possible thinning above the trimline. We conclude that the melt rate and sea-level contribution of the Patagonian Icefields increased markedly in the twentieth century.

The Andes form one of the world's great mountain ranges, and the extreme altitudinal, latitudinal and climatic variability of the Chilean Andes provides the setting for a remarkable range of glacial environments. During the Quaternary, glacier advance and recession have reflected variations in important climatic systems such as the southern westerlies and South American Summer Monsoon. As a result, Chile has assumed considerable importance as a location where the patterns and timing of Southern Hemisphere climatic events can be reconstructed, and where models of global climate change can be tested. © 2011 Elsevier B.V.

Climate and environmental changes associated with anthropogenic global warming are being increasingly identified in the European Alps, as seen by changes in long-term high- alpine temperature, precipitation, glacier cover and permafrost. In turn, these changes impact on land-surface stability, and lead to increased frequency and magnitude of natural mountain hazards, including rock falls, debris flows, landslides, avalanches and floods. These hazards also impact on infrastructure, and socio-economic and cultural activities in mountain regions. This paper presents two case studies (2003 heatwave, 2005 floods) that demonstrate some of the interlinkages between physical processes and human activity in climatically sensitive alpine regions that are responding to ongoing climate change. Based on this evidence, we outline future implications of climate change on mountain environments and its impact on hazards and hazard management in paraglacial mountain systems. ©2010 the Royal Society.

The most widespread depositional landforms in many of the upland valleys of the British Isles which have undergone glaciation during the Last Glacial Maximum (LGM) are so-called solifluction sheets. These form a landform-sediment association consisting of smoothed-slopes underlain by poorly-sorted deposits. The timing and nature of sediment deposition is unclear in the absence of a dating framework within which solifluction sheet development can be placed. This paper presents the first dates from these landforms in the British Isles. We used optical dating on deposits exposed at Linhope Burn in the Cheviot Hills of North East England. The results suggest that the bulk of sediment deposition at this site happened over a period spanning the Younger Dryas. We argue that both paraglacial and periglacial processes can account for the main periods of deposition and that the timing of sediment deposition reflects the rapidity with which landform development responded to climatic shifts. © 2010 Royal Scottish Geographical Society.

Features associated with the Hallaig Fault, SE Raasay, are examined. The fault, which runs along the NW slope of the hill mass of Beinn na Leac, is marked by a narrow trench, running for over 3 km NE-SW. About 600 m from its N end, the trench becomes almost obscured for 500 m by a bench composed of talus. SW of this a ridge of talus up to 5 m high occupies the downslope side of the trench for 1.2 km. The total volume of talus is estimated at around 90,000 m3. In the SW, the trench splits into two, separating discrete bedrock areas from the hillside. Possible mechanisms forming the trench and associated features are considered. It is maintained that the features were primarily the result of the reactivation of a listric fault, triggered by isostatic processes during and following deglaciation and that they reached their present form during the Younger Dryas. Maximum vertical movement is estimated at at least 5 m. The unconsolidated sediment comprising the ridge and bench is believed to have been primarily the product of periglacial processes and paraglacial activity. © 2009 the Geologists' Association.

Glacier sediment-landform associations are commonly used as interpretive and predictive tools to reconstruct the nature of past glacial events. Here we provide a regional-scale study of the sediments and landforms around the temperate North Patagonian Icefield, an area with outlet glaciers that terminate in the full range of environments possible in a temperate glacier setting (land-terminating, lake-terminating and tidewater-terminating). We present a regional-scale geomorphological map and sedimentological data collected at 11 outlet glaciers of the icefield. Key sediments and landforms include large tracts of ice-scoured bedrock, extensive sandar, terminal moraines, ice-contact glaciofluvial landforms and evidence of paraglacial slope adjustment following glacier recession. The sediments and landforms developed around the North Patagonian Icefield contrast with those previously identified at other temperate outlet glaciers in Iceland and Alaska, and we argue that this is largely a result of topographic controls on glacier terminal environment (e.g. local relief, topography and geomorphological setting). © 2009 Elsevier Ltd. All rights reserved.

Glaciar León is a temperate, grounded outlet of the eastern North Patagonian Icefield (NPI). It terminates at an active calving margin in Lago Leones, a 10 km long proglacial lake. We take a multidisciplinary approach to its description and use ASTER imagery and clast sedimentology to describe the geomorphology of the glacier and its associated moraines. We date periods of glacier retreat over the last 2500 years using a combination of lichenometric, dendrochronological, cosmogenic and optically stimulated luminescence techniques and show that the glacier receded from a large terminal moraine complex some 2500 years ago and underwent further significant recession from nineteenth-century moraine limits. The moraine dates indicate varying retreat rates, in conjunction with significant downwasting. The bathymetry of Lago Leones is characterized by distinct ridges interpreted as moraine ridges that dissect the lake into several basins, with water depths reaching 360 m. The fluctuations of Glaciar León appear to have been controlled by the interplay between climatic forcing and calving dynamics. © 2008 SAGE Publications.

This study uses geomorphological, dendrochronological, and archival research to investigate the pattern, chronology, and sedimentology of debris-flow deposits in two reaches of the Zailiiskiy Alatau range of the Tien Shan mountains, Kazakhstan. Steep and narrow low-order tributary valleys in this environment promote rapid coarse sediment transfer to trunk streams and, in wider trunk valley reaches, locally result in development of debris-flow assemblages and terraced sequences of coarse-grained fluvial sediments. Since the mid-19th century the region has experienced 23 documented large-scale debris flows, including 14 in the study area, and these coincide with a period of climate warming. The majority of recorded events are attributed to the failure of moraine-dammed lakes, while the remainder were triggered by intense summer rainstorms. Landform-sediment assemblages investigated here have extended the documentary record by identifying at least 6 major debris-flow assemblages dating respectively from sometime before the early 17th century, ca. 1607-1633, ca. 1702-1728, ca. 1725-1751, ca. 1769-1795, and the midlate 18th century. The geomorphological record of debris flows spanning the 17th to 19th centuries indicates therefore that high-magnitude events occurred also during the cooler climatic conditions of the Little Ice Age, although it is suggested that these events may have coincided with short-lived phases of glacier retreat. Debris flows in this environment may be considered as an important component of the paraglacial response to glacier recession, and this has clear implications for future patterns of valley floor development and its interaction with human activity. © 2008 Regents of the University of Colorado.

Many relict rock glaciers and protalus lobes have been described in mountainous areas of the British Isles. This paper reviews their distribution, chronology, supposed origin and development, and places the research within current investigations and knowledge. Rock glaciers and protalus lobes are located in a number of different topographic locations and settings. They developed at the base of steep cliffs following the catastrophic failure of rock faces, at the base of scree slopes following the gradual accumulation of rock debris and in association with glaciers. Protalus lobes probably developed in response to the permafrost creep of talus material while rock glaciers formed through the deformation and sliding of large bodies of buried ice. Rock glaciers probably developed, or were last active, during the Younger Dryas, although the possibility exists that some of these landforms are Dimlington Stadial in age. The development of protalus lobes during the Younger Dryas suggests that precipitation levels were low and permafrost was widespread during this time. The lack of rock glaciers (sensu stricto) in the British Isles compared with other mountain areas is believed to be a consequence of the rock type and relative scarcity of weathered debris for their formation rather than a lack of suitable sites or appropriate environmental conditions. Copyright © 2007 John Wiley & Sons, Ltd.

The use of digital terrain mapping in determining the anatomy of the Late Devensian British-Irish Ice Sheet at a resolution of 500m cell size is illustrated for Boulton et al.'s 1985 and 1991 models and Lambeck's 1995 model of the ice sheet at its maximum extent as an independent ice mass. Area and volume of the ice sheet are given for each model and the spatial pattern of ice thickness shown in maps. The analyses show that if no account is taken of topography beneath the ice surface, models will seriously overestimate ice volume. It is suggested that as reconstructions of the ice sheet improve, detailed models of ice thickness at the resolution given in this paper may be of value in determining the contribution of the ice sheet to sea surface changes as well as in determining the effects of ice loading on glacio-isostasy, neotectonics and possibly on paraglacial processes in areas of high relief. Copyright © 2007 John Wiley & Sons, Ltd.

This paper presents new mapping of the glacial geomorphology of southern South America between latitudes 38°S and 56°S, approximately the area covered by the former Patagonian Ice Sheets. Glacial geomorphological features, including glacial lineations, moraines, meltwater channels, trimlines, sandur and cirques, were mapped from remotely sensed images (Landsat 7 ETM+, pan-sharpened Landsat 7 and ASTER). The landform record indicates that the Patagonian Ice Sheets consisted of 66 main outlet glaciers, together with numerous local cirque glaciers and independent ice domes in the surrounding mountains. In the northern part of the mapped area, in the Chilean Lake District (38-42°S), large piedmont glaciers developed on the western side of the Andes and the maximum positions of these outlet glaciers are, in general, marked by arcuate terminal moraines. To the east of the Andes between 38°S and 42°S, outlet glaciers were more restricted in extent and formed "alpine-style" valley glaciers. Along the eastern flank of the Andes south of ∼45°S a series of large fast-flowing outlet glaciers drained the ice sheet. The location of these outlet glaciers was topographically controlled and there was limited scope for interactions between individual lobes. West of the Andes at this latitude, there is geomorphological evidence for an independent ice cap close to sea level on the Taitao Peninsula. The age of this ice cap is unclear but it may represent evidence of glacier growth during the Antarctic Cold Reversal and/or Younger Dryas Chronozone. Maximum glacier positions are difficult to determine along much of the western side of the Andes south of 42°S because of the limited land there, and it is assumed that most of these glaciers had marine termini. In the south-east of the mapped area, in the Fuegan Andes (Cordillera Darwin), the landform record provides evidence of ice-sheet initiation. By adding published dates for glacier advances from the literature we present maps of pre-Last Glacial Maximum (LGM) glacier extent, LGM extent and the positions of other large mapped moraines younger than LGM in age. A number of large moraines occur within the known LGM limits. The age of these moraines is unknown but, since many of them lie well outside the established maximum Neoglacial positions, the possibility that they reflect a return to glacial climates during the Younger Dryas Chronozone or Antarctic Cold Reversal cannot be discounted. © 2008 Elsevier Ltd. All rights reserved.

Despite being rich in later prehistoric and historic archaeology that includes megalithic monuments, Bronze age copper mines and medieval castles, the Mizen Peninsula, south-west Ireland, has revealed little about its stone age past. Evidence for a Mesolithic presence in SW Ireland is rare and, to date, all archaeological finds of this age in Co. Cork are further north and east of the Mizen Peninsula. However a recent palaeoecological study of pollen, non-pollen palynomorph, plant macrofossil and microscopic charcoal data from a peat bog located near Mount Gabriel has provided evidence for disturbances, characterised by fire disturbance of woodland and exploitation of wetlands, since ca. 8400 years B.P. Two working hypotheses are considered to explain these disturbances: human activity or natural agencies. If the human activity hypothesis is accepted, they represent the first possible evidence of a Mesolithic presence on the Mizen Peninsula.

Geomorphological mapping, sedimentology, lichenometry and dendrochronology were used to assess the nature and timing of glacier recession, moraine development and catastrophic mass movements in a tributary of the Leones valley, east of the Hielo Patagónico Norte, Chile. We show that during the 'Little Ice Age' Glaciar Calafate advanced downvalley to produce a terminal moraine. Recession of the glacier from this position occurred in the 1870s and produced a moraine dammed lake. In late 2000 a large rockfall into the lake breached the moraine and triggered a glacial lake outburst flood (GLOF) that entrained and subsequently deposited some 2 × 106 m3 of material. We interpret this event as a delayed paraglacial response to the retreat of Glaciar Calafate during the twentieth century. © 2006 Edward Arnold (Publishers) Ltd.

The San Rafael Glacier is one of the largest and most dynamic outlet glaciers of the North Patagonian Icefield, Chile. The contemporary glacier calves into a large tidal laguna, which is partially impounded by a large arcuate moraine. This moraine, termed the 'Témpanos' moraine, marks the former extent of an expanded San Rafael Glacier and is of an unknown age. Here we describe the geomorphology and sedimentology of the 'Témpanos' moraine and relate these to styles of glacier advance and recession. The 'Témpanos' moraine attains a maximum height in excess of 40m and is either single-crested with a gentle ice-proximal face and steep distal face, or consists of multiple crests superimposed on a gentle slope. The internal composition of the moraine is variable, comprising diamicton, sorted sedimentary facies (silts, sands and gravel) and laminites. We interpret these sediments as evidence that the San Rafael Glacier advanced over a former proglacial area, culminating in the formation of the 'Témpanos' moraine. This advance deformed a carpet of lacustrine or marine mud, which was eroded from its original location, transported and smeared over the glacier bed as a subglacial deposit. We use these sedimentary descriptions as the basis for a reconstruction of the Holocene fluctuations of the glacier. Copyright © 2006 John Wiley & Sons, Ltd.

Whalebacks are convex landforms created by the smoothing of bedrock by glacial processes. Their formation is attributed to glacial abrasion either by bodies of subglacial sediment sliding over bedrock or by individual clasts contained within ice. This paper reports field measurements of sediment depth around two whaleback landforms in order to investigate the relationship between glacigenic deposits and whaleback formation. The study site, at Lago Tranquilo in Chilean Patagonia, is situated within the Last Glacial Maximum (LGM) ice limits. The two whalebacks are separated by intervening depressions in which sediment depths are generally 0.2 to 0.3 m. Two facies occur on and around the whalebacks. These facies are: (1) angular gravel found only on the surface of the whalebacks, interpreted as bedrock fracturing in response to unloading of the rock following pressure release after ice recession, and (2) sandy boulder-gravel in the sediment-filled depressions between the two whalebacks, interpreted as an ice-marginal deposit, with a mixture of sediment types including basal glacial and glaciofluvial sediment. Since the whalebacks have heavily abraded and striated surfaces but are surrounded by only a patchy and discontinuous layer of sediment, the implication is that surface abrasion of the whalebacks was achieved primarily by clasts entrained in basal ice, not by subglacial till sliding.

Holocene alluvial landforms in the Macgillycuddy's Reeks, southwest Ireland, were investigated to determine the controls and timing of postglacial geomorphic activity. Detailed geomorphologic analysis of three alluvial-fan and debris cones within high-level cirque basins demonstrates evidence of episodic phases of late Holocene surface aggradation and incision. Radiocarbon dates from peat horizons above and below inorganic units show that phases of aggradation cluster into two distinct periods, the first after 230-790 calibrated (cal.) yr A.D. and the second from 1510 cal. yr A.D. to the present. An additional phase of fan aggradation at one site is dated after 1040-1280 cal. yr A.D. All three phases coincide with episodes of enhanced late Holocene valley-floor alluviation and debris-flow activity from upland Britain. Alluvial fans and debris cones have developed primarily as a result of the resedimentation of late Midlandian (Wisconsin) drift and talus slopes, and mobilization of materials involved flooding, transitional-flow, and debris-flow processes. Pollen analysis of peat horizons interbedded with alluvial-fan and debris-cone sediments indicates that land-use changes were an important factor in lowering the threshold for local slope erosion. Phases of aggradation also coincide with well-documented episodes of climate change, and, hence, fan development is probably a function of both anthropogenic and climatic forcing. A sequence of events may have involved initial slope destabilization due to overgrazing and removal of vegetation that was followed by debris mobilization and fan aggradation during intense rainstorms associated with climate change.

This article addresses the problem of how to distinguish between natural and humanly modified features of the cultural landscape with reference to clitter (boulder and stone) masses in the south-west of England using the example of Leskernick hill, Bodmin Moor with its well-preserved Bronze Age settlement. We first set out a series of criteria for distinguishing between natural and humanly placed stones on the basis of a series of formal geomorphological criteria. We then discuss the stones from an archaeological perspective setting out a series of archaeological criteria by means of which we can recognize the presence of humanly modified stones. From this basis we discuss four examples in detail. Finally we attempt to interpret the significance of the cultural modification of stone masses, previously regarded by both archaeologists and geomorphologists as being entirely natural in origin, by challenging the very culture/nature distinction for ascribing meaning on which the previous considerations are made. Whilst acknowledging that the distinction between a stone that has been moved by human agency, and one that has not, is important for interpretation this does not make it more or less culturally significant.

This article explores some of the philosophical and practical issues concerning the geomorphological exploration and study of landscapes. It argues that reductionist process geomorphology cannot account for emergent structures at the largest scales, and it discusses the ways in which geomorphology might develop in the future. Geography © 1999.

Recent philosophical discussions on the nature of geomorphology (Bassett 1994; Richards 1994; Rhoads 1994) have concluded that the way forward in geomorphological explanation is through either an empiricist or a realist approach. This paper draws lessons from quantum mechanics and the related concepts of decoherence and entanglement to explore the theoretical limitations of both of these existing approaches to geomorphology. It is suggested that empiricist and realist approaches are misguided in their attempts to view the researcher as being in some way 'detached' from the reality of the environmental system under investigation. Instead, this reality is viewed here as being consciousness-dependent. The paper also challenges the claims to represent 'truth', and the deterministic view of causation, which are inherent within empiricist and realist approaches. It concludes by suggesting that an idealist approach to geomorphology - one that recognizes the primacy of consciousness - can better appreciate the unpredictable and probabilistic nature of the world.

Dendrochronology was used to date historical fluctuations of the little-visited Gualas and Reicher Glaciers on the North Patagonian Icefield in southern Chile. Vegetation trimlines dating to AD 1876. 1909 and 1954 show that glacier downwasting and retreat mirrored the patterns found at the neighbouring San Rafael and San Quintin Glaciers. Intermediate stages of recession of the Gualas and Reicher Glaciers dating to the early 1920s, mid-1930s and 1960s are also reflected by similar stages in the San Rafael and San Quintin Glaciers. We propose that the common responses shown by these four glaciers argue for climatic control of their movements and that glacier dynamics in this region are principally controlled by changes in precipitation rather than temperature since annual mean temperatures at Cabo Raper, the nearest meteorological station, have shown no trend since the early 1940s whereas precipitation, peaking in the winter months, has varied widely since the 1920s.

This study employs sedimentological indices and lichenometric dating on the lichen species Placopsis patagonica to investigate the nature and age of debris cones which have accumulated at the margins of the downwasting San Rafael Glacier in Chilean Patagonia. These cones appear to have accumulated by the resedimentation of glacigenic deposits by debris flows, with debris movement starting in the early 1980s. Cone activity follows a pattern of intense initial activity and sediment mobilisation followed by increased stability and colonization by vegetation. Three of the four cones had stabilized within 15 years of sediment movement initiation. These features may be seen as being conditioned by glacial activity with second order controls provided by the local climate and sediment supply. The cones have accumulated in a 'paraglacial' environment.

Extreme soil erosion and flooding of roads and properties from agricultural land have been reported in many areas of the United Kingdom. This article reports the impact of a major storm and soil erosion incident which occurred in the village of Ashow, Warwickshire, on 30 August 1996, where erosion rates on a 16ha field were found to be equivalent to circa. 5000 tonnes per square kilometre. Four groups of factors are considered in relation to the damage caused to roads and properties. These include the possible decrease in soil resistance to erosion due to continuous cultivation over many centuries; the removal of hedgerows; the way in which seed beds are prepared, and the timing of seed bed preparation in relation to the likelihood of autumn thunderstorms. Whilst flooding is regarded as an Act of God for insurance purposes, we argue that in specific instances erosion and flooding may be caused more by farming practice than by an Act of God, and that farmers need to be more aware of the likelihood of severe storms, should assess risks of erosion, and should adjust their practices accordingly.

Small-scale turf-banked terraces are widely developed on low- angled slopes above the Neoglacial trimlines of the Oraefi outlet glaciers in southeast Iceland. These features, which have not been previously described in this area, comprise a vegetated riser and a vegetation-free tread. The morphometry of these landforms is shown to be related to slope angle. Rates of soil movement were measured over a 2-yr period using Rudberg pillars and showed maximum displacement of the surface layer of 11 mm yr-1. The environmental controls on the development of the turf-banked terraces are discussed including aspect, slope angle and altitude.

Lichenometry is a dating technique that has problems relating to questionable assumptions. The development of a size frequency approach, previously used in attempts to resolve some of the problems, is described and applied to the dating of four debris flows marginal to the San Rafael Glacier in Southern Chile. This study provides examples of the development's application, its problems and directions for further work. The size frequency approach, based on new assumptions, uses parameters derived from population size frequency distributions of the lichen species Placopsis patagonica to provide relative and absolute dating for rock surfaces. Changes in the shapes of distributions suggest the relative age of populations. Absolute dating is based on a curve (spanning a 24 year time period) derived from mean diameter size/age correlations. A stratified random sampling design permits the use of inferential statistics. Standard deviations and confidence intervals show error margins, the degree of relatedness between neighbouring populations, and populations that are anomalous. One‐way analysis of variance is used to indicate where populations may safely be grouped. The size frequency approach appears to be particularly suitable for use on unstable debris flows where secondary movements are common. The approach also demonstrates that lichen growth and colonization are sensitive to aspect differences and other variations in microhabitat. Copyright © 1994 John Wiley & Sons, Ltd

Subtle yet systematic differences in clast form and size in riser and tread zones on two stone-banked solifluction lobes in Okstindan, North Norway arc observed. Clasts located within risers arc larger and tend to be ‘blockier’ (more equidimcnsional) than those found upon tread surfaces. Such large clasts may act as ‘braking blocks’; retard soil movement in the frontal zone and hence initiate the lobate form. © 1991 Taylor & Francis Group, LLC.