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Analyzing historical maps and Landsat imagery indicates that coastal glaciers in the western Prince William Sound (PWS) have retreated since the end of the Little Ice Age, exhibiting accelerated retreat after the mid-2000s. A multitemporal inventory of 43 glaciers was developed using historical field observations, topographic maps, and Landsat imagery. Area and length measurements are derived from digitized outlines, and center lines are derived from a semi-automatic, geographic information systems (GIS)-based algorithm. Land-based glaciers retreated at a peak rate of 48 m a−1 from the mid-2000s to 2018, more than doubling the average rate of retreat (22 m a−1) for the preceding fifty-year period. From ~1950 to 2018, the total area of land-based glaciers decreased by 228 km2, with 36 percent of the glacier loss occurring after the mid-2000s. Simple upscaling of area and volume changes to unmeasured glaciers across the entire PWS resulted in an estimated aggregate glacier mass loss of 379 Gt, equivalent to a 1.047 mm rise in sea level from the 1950s to 2018. Tidewater glaciers respond asynchronously with differing periods of peak area and length loss and lower average rate of retreat compared to land-based glaciers. Glacier retreat correlates with increased summer and winter temperatures and decreased winter precipitation.

This review article describes the main probable causes of glacier fluctuations in the Cordillera Blanca since the end of the Little Ice Age. The Cordillera Blanca glaciers reached their last maximum extent during the Little Ice Age and have been retreating since the second half of the 19th century. The progressive glacier recession continued throughout the 20th century but was interrupted several times by periods of glacier advances. The last of these advances took place at the end of the 20th century. However, glacier advances were too short to compensate for the total glacier loss. The major phases of advance and retreat of glacier fluctuations have been well documented and climate changes seem to be their most probable drivers. However, interpreting the climatic forcing that causes such a change in the mass balance remains problematic. The response of tropical glaciers to climatic forcing is complex and glacier recession is likely to involve other components of the energy balance in thermally homogenous areas.

The Himalayan glaciers, as unique reservoirs of freshwater for densely populated Asian countries, have been receiving considerable attention in public and scientific research. However, little is known about their long‐term fluctuations as related to climate variability. Herein, we reconstructed glacier fluctuation events by tree ring‐based moraine dating and repeated photographs. We assessed these fluctuations over the past 200 years in the Gangapurna and Annapurna III glaciers, located in the central Himalayas. We detected five major glacier fluctuation events in the 1790s, 1920s, 1930s, 1960s, and 1970s. A higher rate of glacier recession was observed from the 1980s onward, coinciding with climate warming. As shown by repeated photographs, the retreating rate of the Gangapurna glacier from 1979 to 2016 (up to 24.4 m yr−1) is much higher than the Annapurna III glacier (7.54 m yr−1) from 1950 to 2016. Their different frontal retreat rates were likely related to microtopography and glacier sizes. Older moraines developed during and after the Little Ice Age (LIA) were already covered by dense forest, presenting the evidence for retreating glaciers and advancing forests in the central Himalayas. Ongoing warming tends to speed up such ecological processes by resetting biophysical environment of the deglaciated forefields. In general, glaciers have shown retreating trends over the last 200 years, presenting a risk for preserving water resources in the Himalayas and nearby regions. Alternatively, advancing forest tends to amplify warming rate by reducing albedo, which is a new issue for investigating ecohydrological feedbacks between mountain forests, climate, and water resources. Plain Language Summary: The Himalayan glaciers, as unique reservoirs of freshwater, have been receiving considerable attention in public and scientific research. However, there is a huge knowledge gap on long‐term glacier fluctuations. For example, Intergovernmental Panel on Climate Change (IPCC) in its Fourth Assessment Report asserted that glaciers in the Himalayas will likely disappear by the year 2035 under the present rate of glacier recession. This statement raised scientific criticisms and presented the necessity to have a better understanding on past glacier fluctuations. However, little is known about long‐term glacier fluctuations and ecological processes on the deglaciated forefields. Herein, we reconstructed glacier fluctuation events by tree ring‐based moraine dating and repeated photographs for the Gangapurna and Annapurna III glaciers over the past 200 years in the central Himalayas. This study presents the first detailed evidence for the fluctuation history of Himalayan glaciers over the past 200 years. According to the minimum age of the moraines, the glacier retreat occurred during the 1790s with successive recessions during the 1920s, 1930s, 1960s, and 1980s. The central Himalayas are characterized by retreating glaciers and advancing forest during the past 200 years, presenting a challenge for ecological assessment and resource management. Key Points: History of Himalayan glacier fluctuations over the past 200 years were evidenced by tree ringFive major glacier fluctuation events were dated in the 1790s, 1920s, 1930s, 1960s, and 1970s and a higher rate of recession was observed during the recent decadesThe central Himalayas is characterized by retreating glaciers and advancing forests over the past 200 years [ABSTRACT FROM AUTHOR]

Analyzing historical maps and Landsat imagery indicates that coastal glaciers in the western Prince William Sound (PWS) have retreated since the end of the Little Ice Age, exhibiting accelerated retreat after the mid-2000s. A multitemporal inventory of 43 glaciers was developed using historical field observations, topographic maps, and Landsat imagery. Area and length measurements are derived from digitized outlines, and center lines are derived from a semi-automatic, geographic information systems (GIS)-based algorithm. Land-based glaciers retreated at a peak rate of 48 m a-1 from the mid-2000s to 2018, more than doubling the average rate of retreat (22 m a-1) for the preceding fifty-year period. From ~1950 to 2018, the total area of land-based glaciers decreased by 228 km², with 36 percent of the glacier loss occurring after the mid-2000s. Simple upscaling of area and volume changes to unmeasured glaciers across the entire PWS resulted in an estimated aggregate glacier mass loss of 379 Gt, equivalent to a 1.047 mm rise in sea level from the 1950s to 2018. Tidewater glaciers respond asynchronously with differing periods of peak area and length loss and lower average rate of retreat compared to land-based glaciers. Glacier retreat correlates with increased summer and winter temperatures and decreased winter precipitation. [ABSTRACT FROM AUTHOR]

Elucidating the timing and regional extent of abrupt climate events during the last glacial-interglacial transition (∼18–11.5 ka) is critical for identifying spatial patterns and mechanisms responsible for large-magnitude climate events. The record of climate change in the Southern Hemisphere during this time period, however, remains scarce and unevenly distributed. We present new geomorphic, chronological, and equilibrium line altitude (ELA) data from a climatically sensitive mountain glacier at Monte San Lorenzo (47°S), Central Patagonia. Twenty-four new cosmogenic 10 Be exposure ages from moraines provide a comprehensive glacial record in the mid-latitudes of South America, which constrain the timing, spatial extent and magnitude of glacial fluctuations during the Antarctic Cold Reversal (ACR, ∼14.5–12.9 ka). Río Tranquilo glacier advanced and reached a maximum extent at 13.9 ± 0.7 ka. Three additional inboard moraines afford statistically similar ages, indicating repeated glacier expansions or marginal fluctuations over the ACR. Our record represents the northernmost robust evidence of glacial fluctuations during the ACR in southern South America, documenting not only the timing of the ACR maximum, but also the sequence of glacier changes within this climate event. Based on ELA reconstructions, we estimate a cooling of >1.6–1.8 °C at the peak of the ACR. The Río Tranquilo record along with existing glacial reconstructions from New Zealand (43°S) and paleovegetation records from northwestern (41°S) and central-west (45°S) Patagonia, suggest an uniform trans-Pacific glacier-climate response to an ACR trigger across the southern mid-latitudes. We posit that the equatorial migration of the southern westerly winds provides an adequate mechanism to propagate a common ACR signal across the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

This review article describes the main probable causes of glacier fluctuations in the Cordillera Blanca since the end of the Little Ice Age. The Cordillera Blanca glaciers reached their last maximum extent during the Little Ice Age and have been retreating since the second half of the 19th century. The progressive glacier recession continued throughout the 20th century but was interrupted several times by periods of glacier advances. The last of these advances took place at the end of the 20th century. However, glacier advances were too short to compensate for the total glacier loss. The major phases of advance and retreat of glacier fluctuations have been well documented and climate changes seem to be their most probable drivers. However, interpreting the climatic forcing that causes such a change in the mass balance remains problematic. The response of tropical glaciers to climatic forcing is complex and glacier recession is likely to involve other components of the energy balance in thermally homogenous areas. [ABSTRACT FROM AUTHOR]

Abstract: Glacier-dammed lakes and their associated jökulhlaups cause severe flooding in downstream areas and substantially influence glacier dynamics. Brady Glacier in southeast Alaska is well suited for a study of these phenomena because it presently dams 10 large (>1km2) lakes. Our objectives are to demonstrate how Brady Glacier and its lakes have co-evolved in the past and to apply this knowledge to predict how the glacier and its lakes will likely evolve in the future. To accomplish these objectives, we georeferenced a variety of maps, airphotos, and optical satellite imagery to characterize the evolution of the glacier and lakes. We also collected bathymetry data and created bathymetric maps of select lakes. Despite small advances and retreats, the main terminus of Brady Glacier has changed little since 1880. However, it downwasted at rates of 2–3m/y between 1948 and 2000, more than the regional average. The most dramatic retreat (2km) and downwasting (120m) have occurred adjacent to glacier-dammed lakes and are primarily the result of calving. Brady Glacier is a former tidewater glacier. With continued downwasting, Brady Glacier may return to a tidewater regime and enter into a phase of catastrophic retreat. The situation at Brady Glacier is not unique, and the lessons learned here can be applied elsewhere to identify future glacier-dammed lakes, jökulhlaups, and glacier instability. [Copyright &y& Elsevier]

The object of our study is a cirque glacier located in an alpine-type terrain near Mount Chersky in the Baikalsky Ridge, about 18 km to the west of the northern basin of Lake Baikal (Russia). We analysed a sediment record from the pro-glacial Lake Gitara of this glacier by X-ray fluorescent technique with synchrotron radiation (equipment of Multiple Access Centre SSTRC within the framework of State Contract 16.552.11.7044) at 1 mm scan resolution. The depth–age model of the core was constructed by 210Pb and 137Cs activity using the constant rate of supply model. The intensity of the glacier fluctuation for the last 160 years was calculated from the ratio of terrigenous elements supplied into Lake Gitara with meltwater. We defined five (c. 1880, 1905, 1918, 1950 and from 1968 to the present) significant periods of increased glacier flow for the last 160 years. The periods centred on 1905 and 1918 were probably characterised by the advance of the glacier, while its retreat was recorded in c. 1880, 1950 and from 1968 to the present. [ABSTRACT FROM PUBLISHER]

Fluctuation history of Midui glacier in the southeastern Tibet since the Little Ice Age (LIA) was reconstructed by the dating of lateral and terminal moraines using tree rings. Four conversions of glacier advance/stabilization to retreat were identified at around 1767, 1875, 1924 and 1964. The glacier reached its LIA maximum position at 1767. The fluctuations are consistent with those of other glaciers from the Tibetan Plateau, the Rockies and the Alps, suggesting high spatial coherency of glacier fluctuations in the Northern Hemisphere. Comparison with the summer temperature reconstruction in the southeastern Tibetan Plateau indicated that the Midui glacier fluctuation may be related to temperature variation on the centennial timescale. On the decadal scale, the fluctuation could correspond to cold/warm variation with an 8-year lag on average. [ABSTRACT FROM AUTHOR]

We utilized dendrochronology and precise elevation-constrained mapping to date glacially overridden and drowned trees at the margin of Brady Glacier in southeast Alaska. This technique allowed determination of the timing of the former tidewater glacier’s last advance and consequent formation and filling of two marginal lakes. The subfossil tree-ring chronology spans the interval from AD 1370 to 1861. Brady Glacier impounded Spur Lake to an elevation of 83 m a.s.l. around 1830 and 121 m a.s.l. around 1839. Soon after, Spur Lake reached 125 m a.s.l. and began to overflow a stable bedrock sill. The glacier continued to advance, thickening by at least 77 m between c. 1844 and 1859 at a site down-glacier of Spur Lake on the opposite glacier margin. Farther down-glacier, North Trick Lake began to form by 1861 and reached its highest elevation at approximately 130 m a.s.l. when Brady Glacier reached its maximum extent around 1880. Our findings add precision to the chronology of the last advance of Brady Glacier and provide insight into the evolution of glacier-dammed lakes and calving glaciers. [ABSTRACT FROM AUTHOR]

Abstract: Tree-ring crossdates from glacially killed logs show that Tebenkof Glacier advanced into a forefield forest in the AD 710s and 720s. Recession from this First Millennium AD (FMA) advance occurred before the 950s, after which the ice margin readvanced in the 1280s to 1320s at the start of the Little Ice Age (LIA). A more extensive LIA advance was underway from the 1640s to 1670s, and the terminus stayed at or near its LIA maximum until the 1890s. These are the first absolute tree-ring crossdates for a FMA glacier advance in North America and support growing evidence from northwestern North America and Europe for a significant cool interval in the centuries around AD 500. [Copyright &y& Elsevier]

• There are differences between detrital and leached ε Nd (△ ε Nd) in Svalbard bedrock. • The leached ε Nd are more radiogenic than detrital ε Nd in Svalbard fjord sediments. • The △ ε Nd are generally higher during the periods of glacier advances. • Glacial incongruent weathering could cause higher △ ε Nd. • △ ε Nd could be a tracer for glacial fluctuation and associated nutrient inputs. Neodymium (Nd) isotopes in leached authigenic components of marine sediments have been increasingly used as a tracer of past ocean-water masses. Despite the general assumption that the Nd isotopic composition of solutes released during chemical weathering fingerprints the source rocks on continents, preferential dissolution of easily dissolvable phases may result in significant deviations in Nd isotopic composition between the solutes and the source rocks, with potential implications for the utility of Nd isotopes in paleoenvironmental studies. Here, we present the Nd isotopic compositions of leached and detrital fractions separated from bedrock and marine sediment samples from the Svalbard archipelago. Our goal is to further understand the behaviour of Nd isotopes during chemical weathering in glacial catchments and evaluate how glacier fluctuations and associated weathering congruency may have affected the export of dissolved Nd isotope signatures to seawater. Our results confirm that terrestrial weathering on Svalbard causes considerable Nd isotopic decoupling between the leached and detrital fractions of fjord sediments (△ ε Nd), resulting from the preferential dissolution of marine precipitates in glaciated catchments dominated by sedimentary rocks. We also show that the degree of Nd isotopic decoupling has fluctuated in response to climate variability on Svalbard during the Holocene, which is also as suggested by the occurrence of generally higher △ ε Nd values during periods of glacier advances in sediment cores retrieved from two different fjords (Dicksonfjorden and Woodfjorden). We posit that the high △ ε Nd values can be ascribed to incongruent chemical weathering of fresh rock flour produced by glacial abrasion. This finding suggests that the degree of Nd isotopic decoupling could be used as a new proxy for tracing glacial fluctuations and associated glacier-derived nutrient inputs to the marine realm. [ABSTRACT FROM AUTHOR]

Climate change in the European Alps during the 20th century has beencharacterized by increases in minimum temperatures of about 2 deg.C,a more modest increase in maximum temperatures, little trend in precipitation data, and a general decrease of sunshine duration through to the mid-1980s. Temperature increase has been most intense in the 1940s, followed by the 1980s. The warming experienced since the early 1980s, while synchronous with the global warming, is of far greater amplitude and reaches close to 1 deg.C for this ensemble average and upto 2 deg.C for individual sites. Such changes caused pronounced effects in the glacial and periglacial belts. Since the middle of the past century- the end of the Little Ice Age-the glacierization of the European Alps has lost about 30 to 40% in surface area and around half its original volume. The estimated total glacier volume in the European Alps was some 130 km3 for the mid-1970s, but strongly negative mass balances have caused an additional loss of about 10 to 20% of this remaining ice volume since 1980. Periglacial permafrost in the Alps today occupies an area comparable to the glacierized area and must have been affected as well, but its secular evolution is much less well known. Simulations of high- resolution climatologies for double-CO2 situations using regional climate models (RCM) with a 20-kmhorizontal grid give generally higher winter temperatures, a more marked increase in summer temperatures, indications that temperature increases more at higher elevations than at lower altitudes, and higher/more intense precipitation in winter, but much dryer conditions in summer. Under such conditions, the Alps would lose major parts of their glacier cover within decades, warming of cold firn areas at high altitudes could become pronounced and lower limits of permafrost occurrence in the Alps could rise by several hundred meters. Pronounced disequilibria could result, in the water cycle, in mass wasting processes, a [ABSTRACT FROM AUTHOR]