scholarly journals Accelerating shrinkage of Patagonian glaciers from the Little Ice Age (~AD 1870) to 2011

2012 ◽  
Vol 58 (212) ◽  
pp. 1063-1084 ◽  
Author(s):  
B.J. Davies ◽  
N.F. Glasser
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
South American ◽  
Ice Caps ◽  
Mountain Glaciers ◽  
Northern Patagonia ◽  
Area Loss ◽  
Southern Patagonia

AbstractWe used Little Ice Age (LIA) trimlines and moraines to assess changes in South American glaciers over the last ~140 years. We determined the extent and length of 640 glaciers during the LIA (~AD1870) and 626 glaciers (the remainder having entirely disappeared) in 1986, 2001 and 2011. The calculated reduction in glacierized area between the LIA and 2011 is 4131 km2 (15.4%), with 660 km2 (14.2%) being lost from the Northern Patagonia Icefield (NPI), 1643km2 (11.4%) from the Southern Patagonia Icefield (SPI) and 306 km2 (14.4%) from Cordillera Darwin. Latitude, size and terminal environment (calving or land-terminating) exert the greatest control on rates of shrinkage. Small, northerly, land-terminating glaciers shrank fastest. Annual rates of area loss increased dramatically after 2001 for mountain glaciers north of 52° S and the large icefields, with the NPI and SPI now shrinking at 9.4km2a-1 (0.23% a-1) and 20.5 km2a-1 (0.15% a-1) respectively. The shrinkage of glaciers between 52° S and 54° S accelerated after 1986, and rates of shrinkage from 1986 to 2011 remained steady. Icefield outlet glaciers, isolated glaciers and ice caps south of 54° S shrank faster from 1986 to 2001 than they did from 2001 to 2011.

scholarly journals Historical record of Holochilus vulpinus (Rodentia, Sigmodontinae) from northern Patagonia, Argentina

Mammalia ◽  
2018 ◽  
Vol 82 (6) ◽  
pp. 622-625
Author(s):  
Federico L. Agnolin ◽  
Sergio O. Lucero ◽  
Julio Torres
Keyword(s):  
Geographical Distribution ◽  
Little Ice Age ◽  
Historical Record ◽  
Ice Age ◽  
Northern Patagonia ◽  
North Patagonia ◽  
Rio Negro ◽  
Xix Century

Abstract Marsh rats of the species Holochilus vulpinus inhabit mesic and humid environments. For this reason, it is frequently used in paleoenviromental studies to infer past humid conditions. Holocene archeological record indicates that H. vulpinus had a wider geographical distribution than today. Its regional extinction in north Patagonia at the XIX century was attributed to the dry and cold Little Ice Age (LIA). Here we present the finding of a specimen of H. vulpinus from northeastern Patagonia (Valcheta stream, Río Negro province, Argentina), just at the end of LIA. Implications of this novel historical record are discussed.

scholarly journals South Atlantic Surface Boundary Current System during the Last Millennium in the CESM-LME: The Medieval Climate Anomaly and Little Ice Age

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 299
Author(s):  
Fernanda Marcello ◽  
Ilana Wainer ◽  
Peter R. Gent ◽  
Bette L. Otto-Bliesner ◽  
Esther C. Brady
Keyword(s):  
Little Ice Age ◽  
South Atlantic ◽  
Subtropical Gyre ◽  
Ice Age ◽  
Surface Boundary ◽  
South American ◽  
Last Millennium ◽  
Medieval Climate Anomaly ◽  
The South ◽  
Gyre Circulation

Interocean waters that are carried northward through South Atlantic surface boundary currents get meridionally split between two large-scale systems when meeting the South American coast at the western subtropical portion of the basin. This distribution of the zonal flow along the coast is investigated during the Last Millennium, when natural forcing was key to establish climate variability. Of particular interest are the changes between the contrasting periods of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The investigation is conducted with the simulation results from the Community Earth System Model Last Millennium Ensemble (CESM-LME). It is found that the subtropical South Atlantic circulation pattern differs substantially between these natural climatic extremes, especially at the northern boundary of the subtropical gyre, where the westward-flowing southern branch of the South Equatorial Current (sSEC) bifurcates off the South American coast, originating the equatorward-flowing North Brazil Undercurrent (NBUC) and the poleward Brazil Current (BC). It is shown that during the MCA, a weaker anti-cyclonic subtropical gyre circulation took place (inferred from decreased southern sSEC and BC transports), while the equatorward transport of the Meridional Overturning Circulation return flow was increased (intensified northern sSEC and NBUC). The opposite scenario occurs during the LIA: a more vigorous subtropical gyre circulation with decreased northward transport.

scholarly journals Mountain glaciers of southeast Siberia: current state and changes since the Little Ice Age

2014 ◽  
Vol 55 (66) ◽  
pp. 167-176 ◽  
Author(s):  
E.Yu. Osipov ◽  
O.P. Osipova
Keyword(s):  
Little Ice Age ◽  
Snow Accumulation ◽  
Ice Age ◽  
High Mountain ◽  
Late 20Th Century ◽  
Glacier Inventory ◽  
Mountain Glaciers ◽  
Current State ◽  
Field Investigations ◽  
Glacier Changes

AbstractContemporary glaciers of southeast Siberia are located on three high-mountain ridges (east Sayan, Baikalsky and Kodar). In this study, we present an updated glacier inventory based on high- to middle-resolution satellite imagery and field investigations. The inventory includes 51 glaciers with a total area of - 15 km2. Areas of individual glaciers vary from 0.06 to 1.33 km2, lengths from 130 to 2010 m and elevations from 1796 to 3490 m. The recent ice maximum extents (Little Ice Age) have been delineated from terminal moraines. On average, debris-free surface area shrunk by 59% between 1850 and 2006/11 (0.37% a–1), by 44% between 1850 and 2001/02 (0.29% a–1) and by 27% between 2001/02 and 2006/11 (3.39% a–1). The Kodar glaciers have experienced the largest area shrinkage, while the area loss on Baikalsky ridge was more moderate. Glacier changes are mainly related to regional summer temperature increase (by 1.7-2.6C from 1970 to 2010). There are some differences in glacier response due to different spatial patterns of snow accumulation, local topography (e.g. glacier elevation, slope) and geological activity. The studied glaciers (especially of Kodar ridge) are the most sensitive in Siberia to climate change since the late 20th century.

scholarly journals Rapid Wastage of the Hazen Plateau Ice Caps, Northeastern Ellesmere Island, Nunavut, Canada

2016 ◽  
Author(s):  
Mark C. Serreze ◽  
Bruce Raup ◽  
Carsten Braun ◽  
Douglas R. Hardy ◽  
Raymond S. Bradley
Keyword(s):  
Satellite Data ◽  
Little Ice Age ◽  
Ellesmere Island ◽  
Ice Age ◽  
Aerial Photographs ◽  
Direct Response ◽  
Ice Caps ◽  
Warm Summer ◽  
Plant Recolonization

Abstract. Two pairs of small stagnant ice bodies on the Hazen Plateau of northeastern Ellesmere Island, the St. Patrick Bay ice caps and the Murray and Simmons ice caps, are rapidly shrinking, and the remnants of the St. Patrick Bay ice caps are likely to disappear entirely within the next five years. Vertical aerial photographs of these Little Ice Age relics taken during August of 1959 show that the larger of the St. Patrick Bay ice caps had an area of 7.48 km2, and the smaller one 2.93 km2. The Murray and Simmons ice caps covered 4.37 km2 and 7.45 km2 respectively. Outlines determined from ASTER satellite data for July 2016 show that, compared to 1959, the larger and the smaller of the St. Patrick Bay ice caps had both been reduced to only 5 % of their former area, with the Murray and Simmons ice caps faring better at 39 % and 25 %, likely reflecting their higher elevation. ASTER imagery in conjunction with past GPS surveys documents a strikingly rapid wastage of the St. Patrick Bay ice caps over the last 15 years. These two ice caps shrank noticeably even between 2014 and 2015, apparently in direct response to the especially warm summer of 2015 over northeastern Ellesmere Island. The well-documented recession patterns of the Hazen Plateau ice caps over the last 55+ years offer an opportunity to examine the processes of plant recolonization of polar landscapes.

scholarly journals Little ice age advance and retreat of Glaciar Jorge Montt, Chilean Patagonia, recorded in maps, air photographs and dendrochronology

2011 ◽  
Vol 7 (5) ◽  
pp. 3131-3164 ◽  
Author(s):  
A. Rivera ◽  
M. Koppes ◽  
C. Bravo ◽  
J. C. Aravena
Keyword(s):  
Little Ice Age ◽  
Dynamic Responses ◽  
Ice Age ◽  
Past Century ◽  
Present Position ◽  
Tidewater Glaciers ◽  
The Past ◽  
Chilean Patagonia ◽  
Southern Patagonia ◽  
Induced Changes

Abstract. Glaciar Jorge Montt (48°20' S/73°30' W), one of the main tidewater glaciers of the Southern Patagonian Icefield (SPI), has experienced the fastest frontal retreat observed in Patagonia during the past century, with a recession of 19.5 km between 1898 and 2011. This record retreat uncovered trees overridden during the Little Ice Age (LIA) advance of the glacier. Samples of these trees were dated using radiocarbon methods, yielding burial ages between 460 and 250 cal yr BP. The dendrochronology and maps indicate that Glaciar Jorge Montt was at its present position before the beginning of the LIA, in concert with several other glaciers in Southern Patagonia, and reached its maximum advance position between 1650 and 1750 AD. The post-LIA retreat is most likely triggered by climatically induced changes during the 20th century, however, Glaciar Jorge Montt has responded more dramatically than its neighbours. The retreat of Jorge Montt opened a new fjord 19.5 km long, and up to 391 m deep, with a varied bathymetry well correlated with glacier retreat rates, suggesting that dynamic responses of the glacier are at least partially connected to near buoyancy conditions at the ice front, resulting in high calving fluxes, accelerating thinning rates and rapid ice velocities.

Stratigraphic signature of the Perito Moreno ice-dammings during the Little Ice Age (southern Patagonia, Argentina)

The Holocene ◽  
2021 ◽  
pp. 095968362110604
Author(s):  
Mauro Caffau ◽  
Emanuele Lodolo ◽  
Federica Donda ◽  
Massimo Zecchin ◽  
Jorge G Lozano ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Sediment Cores ◽  
Testate Amoebae ◽  
High Energy ◽  
Environmental Indicators ◽  
Laminated Sediments ◽  
Ice Age ◽  
Energy Conditions ◽  
Lake Basin ◽  
Southern Patagonia

The spectacular water outburst occurring semi-periodically when the ice-dam formed by the external front of the Perito Moreno glacier collapses, is one of the most attracting events in the UNESCO ‘Parque Nacional Los Glaciares’ of southern Patagonia. These occurrences have been documented since 1936. Instead, evidence of previous events has been only indirectly provided by dendrochronology analysis. Here we show for the first time radiocarbon-dated sediment cores collected within a small inlet of Brazo Sur, that is, the southern arm of Lago Argentino that record ice-dammings in the Little Ice Age, at 324–266 cal yrs BP, as measured on a vegetal fragment sampled at ca. 14 cm from the top of a core. A common characteristic of the three sediment cores is the abrupt change in the stratigraphic record found at variable depths of 14–18 cm from the top of the cores. This change is marked by a hiatus spanning ca. 3200 years, separating planar-laminated sediments below from an alternation of erosional and depositional events above it, indicating recurring high-energy conditions generated by the emptying of the lake basin. In addition, we observed significant changes in the abundance of environmental indicators as testate amoebae below and above the hiatus. These well-preserved stratigraphic records highlight the key role of glaciolacustine deposits in reconstructing the glacial dynamics and palaeoclimate evolution of a glaciated region.

scholarly journals Recession of Grasshopper Glacier, Montana, Since 1898

1986 ◽  
Vol 8 ◽  
pp. 65-68 ◽  
Author(s):  
Jane G. Ferrigno
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Little Ice Age ◽  
Rocky Mountain ◽  
The United States ◽  
Ice Age ◽  
Positive Mass ◽  
Mountain Glaciers ◽  
If Current ◽  
Central Rocky Mountains

Grasshopper Glacier is a cirque glacier in the central Rocky Mountains of the United States. It is a remnant of the “Little Ice Age”, rather than the more widespread and older Pinedale Glaciation. The glacier has not been monitored on a regular basis and very few maps have been published of the area, but it has been studied, photographed, occasionally mapped, and described by scientific and non-scientific groups, at different times since 1898. These photographic, cartographic, and written records make it possible to trace the fluctuations of this glacier since 1898. Grasshopper Glacier has had periods of positive mass balance, but the overall trend has been negative, with accelerated melting in recent years. It is estimated that Grasshopper Glacier has lost about 50% of its area and as much as 90% of its volume, since 1898. Other Rocky Mountain glaciers are experiencing similar wastage and, if current conditions continue, these glaciers will disappear by the middle of the next century.

scholarly journals Widespread and accelerating glacier retreat on the Lyngen Peninsula, northern Norway, since their ‘Little Ice Age’ maximum

2018 ◽  
Vol 64 (243) ◽  
pp. 100-118 ◽  
Author(s):  
CHRIS R. STOKES ◽  
LISS M. ANDREASSEN ◽  
MATTHEW R. CHAMPION ◽  
GEOFFREY D. CORNER
Keyword(s):  
Little Ice Age ◽  
Winter Precipitation ◽  
Ice Age ◽  
Surface Hydrology ◽  
Northern Norway ◽  
Mountain Glaciers ◽  
Air Temperatures ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Global Sea Level

ABSTRACTThe recession of mountain glaciers worldwide is increasing global sea level and, in many regions, human activities will have to adapt to changes in surface hydrology. Thus, it is important to provide up-to-date analyses of glacier change and the factors modulating their response to climate warming. Here we report changes in the extent of >120 glaciers on the Lyngen Peninsula, northern Norway, where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred. Glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988, 2001 and a new one from 2014, and previously-dated Little Ice Age (LIA) limits. Results show a steady reduction in area (~0.3% a−1) between their LIA maximum (~1915) and 1988, consistent with increasing summer air temperatures, but recession paused between 1988 and 2001, coinciding with increased winter precipitation. Air temperatures increased 0.5°C per decade from the 1990s and the rate of recession accelerated to ~1% a−1 between 2001 and 2014 when glacier area totalled ~95.7 km2. Small glaciers (<0.05 km2) with low maximum elevations (<1400 m) experienced the largest percentage losses and, if warming continues, several glaciers may disappear within the next two decades.

Climatic Fluctuations in Northern Patagonia during the Last 1000 Years as Inferred from Tree-Ring Records

1990 ◽  
Vol 34 (3) ◽  
pp. 346-360 ◽  
Author(s):  
Ricardo Villalba
Keyword(s):  
Tree Ring ◽  
Little Ice Age ◽  
Ice Age ◽  
Dry Period ◽  
Climatic Fluctuations ◽  
Northern Patagonia ◽  
The Andes ◽  
Weather Stations ◽  
Fitzroya Cupressoides

AbstractMillennium-old alerce trees (Fitzroya cupressoides (Mol.) Johnst.) have been used to develop a 1120-year reconstruction of the summer temperature departures for the Andes of northern Patagonia in Argentina. Four main climatic episodes can be distinguished in this proxy paleoclimatic record. The first, a cold and moist interval from A.D. 900 to 1070, was followed by a warm-dry period from A.D. 1080 to 1250 correlative with the Medieval warm epoch of Europe. Afterward, a long, cold-moist period followed from A.D. 1270 to 1670, peaking around A.D. 1340 and 1650. These cold maxima are contemporaneous with two principal Little Ice Age events registered in the Northern Hemisphere. Warmer conditions then resumed between A.D. 1720 and 1790. These episodes are supported by glaciological and palynological data in Patagonia. Following a cold period in the early 1800s, tree-ring indices have oscillated around the long-term mean, except for a warmer period from A.D. 1850 to 1890. Correlations between the Rio Alerce reconstruction and the regional weather stations indicate that the tree-ring variations are correlated with a homogeneous summer weather pattern covering Patagonia east of the Andes from 38° to 50°S.

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