scholarly journals An extreme event between The Little Ice Age and the 20th century: the snow avalanche cycle of 1888 in the Asturian Massif (Northern Spain)

2018 ◽  
Vol 44 (1) ◽  
pp. 187 ◽  
Author(s):  
C. García-Hernández ◽  
J. Ruiz-Fernández ◽  
C. Sánchez-Posada ◽  
S. Pereira ◽  
M. Oliva
Keyword(s):  
20Th Century ◽  
Little Ice Age ◽  
Transition Period ◽  
Extreme Event ◽  
Climate Extremes ◽  
Ice Age ◽  
Snow Avalanche ◽  
Northern Spain ◽  
The North ◽  
The Impact

Between the late Little Ice Age (LIA) cold stage and the early 20th century warmer scenario, a transitional regime characterized by an unstable climatic pattern generated a series of climate extremes affecting mid-latitude mountainous areas, as the Asturian Massif. There, the 1888 snow avalanche cycle appears as the most significant event, standing out among the rest of avalanche cycles recorded in this area during the 1800-2015 period both in terms of the number of damaging avalanches and damages caused by them. Among the factors that explain this event stands out the orographic precipitation phenomenon; the interaction of a cold and wet air mass originating from the North Atlantic with the relief of the Massif, which led to extraordinary snow thicknesses (>2 m) at very low altitudes (500 m a.s.l.), especially in the north-facing, Asturian versant of the Cantabrian Mountains. This allowed the triggering of avalanches in slopes gentler and in lower altitudes than usual, covering longer distances; consequently, avalanches reached more easily the settlements, generally placed at the bottom of the valley or in middle slope positions. The greater impact on the settlements, which suffered 84% of the damages, was the cause of this episode’s high socioeconomic impact (29 people dead, 34 injured, 123 heads of cattle dead, 124 buildings destroyed). These events occurred at a time when the mountain villages were highly populated and subjected to intense exploitation, coinciding with the development of new communication infrastructures in the upper parts of the Massif. Therefore, the 1888 episode constitutes a good example of both the impact of hydrometeorological events in mountain environments under high demographic pressure, and of climate extremes involved in a transition period from cold to warmer weather conditions.

scholarly journals Investigating the Strength of the Indian Monsoons during Climate Extremes with Stable Isotope Records in Corals

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Hannah Varkey ◽  
Richard Mortlock ◽  
Cecilia Mchugh ◽  
Dhiman Mondal
Keyword(s):  
North Atlantic ◽  
Little Ice Age ◽  
Indian Monsoon ◽  
Climate Extremes ◽  
Relative Strength ◽  
Ice Age ◽  
Last Glacial Period ◽  
Salinity Changes ◽  
The North ◽  
The Last Glacial

The Indian monsoon affects the lives of over a billion inhabitants living in southern Asia via the hy-drological cycle. Agriculture on land and freshwater discharge into the ocean. This discharge and nutri-ent cycling are tied with the monsoon cycles that di-rectly impact society and the economy. Previous studies have demonstrated a strong connection be-tween the strength of the Indian monsoon and the cooling of the North Atlantic during climate ex-tremes, such as during the last glacial period 20,000 years ago, and the Little Ice Age (~1300-1870 A.D.). In our study, we compare the relative strength of the monsoon during two different climate states: the Lit-tle Ice Age (LIA) and the modern (2015) with proxy measurements obtained in surface corals from Saint Martin’s Island, Southeast Bangladesh. We used the oxygen-isotope 18O/16O ratio (δ18Oc) of coralline aragonite (CaCO3) to reconstruct changes in the δ18O of seawater (δ18Ow) attributed to freshening from monsoon rains. During both climate states, corals recorded large variations in δ18Oc (up to 2 parts per thousand or ‰). We attribute these changes, in part, to local salinity changes which are reflected by variability in δ18Ow from local riverine discharge. While our records only represent 5-year snapshots and may not be representative of the av-erage climate state, this data does not support that the monsoon was substantially weaker during the LIA compared to the modern. In this study, the coral records indicate subtle patterns of isotopic compo-sition as a function of precipitation and temperature variability, serving as a preliminary for further study through longer records lasting a century. Beyond this, it would better our understanding of interac-tions between extremes in temperature and climate systems.

Abrupt mortality of marine invertebrates at the Younger Dryas-Holocene transition in a shallow inlet of the Goldthwait Sea

The Holocene ◽  
2018 ◽  
Vol 28 (12) ◽  
pp. 1894-1908
Author(s):  
Andréanne Bourgeois-Roy ◽  
Hugo Crites ◽  
Pascal Bernatchez ◽  
Denis Lacelle ◽  
André Martel
Keyword(s):  
Mytilus Edulis ◽  
Marine Invertebrates ◽  
Transition Period ◽  
Marine Invertebrate ◽  
Laurentide Ice Sheet ◽  
The North ◽  
Invertebrate Diversity ◽  
Shell Deposit ◽  
The Impact ◽  
Rapid Environmental Change

The late Pleistocene–early Holocene transition period was characterized by rapid environmental change. Here, we investigate the impact of these changes on the marine invertebrates living in a shallow inlet of the post-glacial Goldthwait Sea. The site is located near Baie-Comeau (QC, Canada), where a number of remarkably well-preserved shell deposits are found along the Rivière aux Anglais Valley on the north shore of the St. Lawrence maritime estuary. Seven phyla of marine invertebrates with a minimum of 25 species or taxa were inventoried in a shell deposit, dominated by a community of Hiatella arctica with Mytilus edulis and barnacles composing the subcommunity. The majority of taxa identified in the shell deposit are boreal and sub-Arctic species; however, temperate species that exist today in the St. Lawrence maritime estuary have not been found. Based on marine invertebrate diversity and δ18O(CaCO3) of Mytilus edulis, the water in the shallow inlet of the Goldthwait Sea must have been cold and saline. The range of AMS 14C ages from 15 Mytilus edulis, constrained to 10,900 and 10,690 cal. yr BP, and exceptional state of preservation of adult and juvenile molluscan specimens suggest the abrupt mortality of entire invertebrate communities due to changing hydrodynamic conditions that included the combined effect of freshwater discharge from the receding Laurentide Ice Sheet and rapid isostatic uplift.

scholarly journals Climatic variability and human impact during the last 2000 years in western Mesoamerica: evidence of late Classic (AD 600–900) and Little Ice Age drought events

2015 ◽  
Vol 11 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
A. Rodríguez-Ramírez ◽  
M. Caballero ◽  
P. Roy ◽  
B. Ortega ◽  
G. Vázquez-Castro ◽  
...  
Keyword(s):  
Human Impact ◽  
Little Ice Age ◽  
Climatic Variability ◽  
Seasonal Migration ◽  
Ice Age ◽  
Cultural Tradition ◽  
Late Classic ◽  
High Pressure Cell ◽  
Western Mexico ◽  
The North

Abstract. We present results of analysis of biological (diatoms and ostracodes) and non-biological (Ti, Ca / Ti, total inorganic carbon, magnetic susceptibility) variables from an 8.8 m long, high-resolution (~ 20 yr sample−1) laminated sediment sequence from Lake Santa María del Oro (SMO), western Mexico. This lake lies at a sensitive location between the dry climates of northern Mexico, under the influence of the North Pacific subtropical high-pressure cell and the moister climates of central Mexico, under the influence of the seasonal migration of the intertropical convergence zone and the North American monsoon (NAM). The sequence covers the last 2000 years and provides evidence of two periods of human impact in the catchment, shown by increases in the diatom Achnanthidium minutissimum. The first from AD 100 to 400 (Early Classic) is related to the shaft and chamber tombs cultural tradition in western Mexico, and the second is related to Post-Classic occupation from AD 1100 to 1300. Both periods correspond to relatively wet conditions. Three dry intervals are identified from increased carbonate and the presence of ostracodes and aerophilous Eolimna minima. The first, from AD 500 to 1000 (most intense during the late Classic, from AD 600 to 800), correlates with the end of the shaft and chamber tradition in western Mexico after ca. AD 600. This late Classic dry period is the most important climatic signal in the Mesoamerican region during the last 2000 years, and has been recorded at several sites from Yucatan to the Pacific coast. In the Yucatan area, this dry interval has been related with the demise of the Maya culture at the end of the Classic (AD 850 to 950). The last two dry events (AD 1400 to 1550 and 1690 to 1770) correspond with the onset of, and the late, Little Ice Age, and follow largely the Spörer and Maunder minima in solar radiation. The first of these intervals (AD 1400 to 1550) shows the most intense signal over western Mexico; however this pattern is different at other sites. Dry/wet intervals in the SMO record are related with lower/higher intensity of the NAM over this region, respectively.

scholarly journals Bunker Cave stalagmites: an archive for central European Holocene climate variability

2012 ◽  
Vol 8 (3) ◽  
pp. 1687-1720 ◽  
Author(s):  
J. Fohlmeister ◽  
A. Schröder-Ritzrau ◽  
D. Scholz ◽  
C. Spötl ◽  
D. F. C. Riechelmann ◽  
...  
Keyword(s):  
Climate Variability ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Age ◽  
Holocene Climate ◽  
Central European ◽  
The North ◽  
The North Atlantic ◽  
Meteoric Precipitation ◽  
Precipitation And Temperature

Abstract. Holocene climate was characterised by variability on multi-centennial to multi-decadal time scales. In central Europe, these fluctuations were most pronounced during winter. Here we present a new record of past winter climate variability for the last 10.8 ka based on four speleothems from Bunker Cave, Western Germany. Due to its central European location, the cave site is particularly well suited to record changes in precipitation and temperature in response to changes in the North Atlantic realm. We present high resolution records of δ18O, δ13C values and Mg/Ca ratios. We attribute changes in the Mg/Ca ratio to variations in the meteoric precipitation. The stable C isotope composition of the speleothems most likely reflects changes in vegetation and precipitation and variations in the δ18O signal are interpreted as variations in meteoric precipitation and temperature. We found cold and dry periods between 9 and 7 ka, 6.5 and 5.5 ka, 4 and 3 ka as well as between 0.7 to 0.2 ka. The proxy signals in our stalagmites compare well with other isotope records and, thus, seem representative for central European Holocene climate variability. The prominent 8.2 ka event and the Little Ice Age cold events are both recorded in the Bunker cave record. However, these events show a contrasting relationship between climate and δ18O, which is explained by different causes underlying the two climate anomalies. Whereas the Little Ice Age is attributed to a pronounced negative phase of the North Atlantic Oscillation, the 8.2 ka event was triggered by cooler conditions in the North Atlantic due to a slowdown of the Thermohaline Circulation.

scholarly journals “Sermo eorum sicut cancer serpit”. Chromatius of Aquileia against heresies

Vox Patrum ◽  
2018 ◽  
Vol 68 ◽  
pp. 443-455
Author(s):  
Miran Sajovic
Keyword(s):  
20Th Century ◽  
Adriatic Sea ◽  
Conference Paper ◽  
The North ◽  
Trade Center ◽  
The Impact ◽  
North End

Bishop Chromatius (in office from 388 to 407), whose episcopal see was a cosmopolitan trade-center at the north end of the Adriatic Sea with the name of Aquileia, was one of the most prominent bishops in the period. He is acquaint­ed with notable figures such as Ambrosius, Hieronymus, Rufinus, and Ioannes Chrysostomus and forth. Before being created a bishop, he was the secretary of bi­shop Valerianus and in the occasion of Council of Aquileia in 381, he had spoken against Arians. This Council was presided by Ambrosius and with its scale it could almost be considered as an ecumenical one. As shown in some of the Chromatius’ sermons, which are unearthed in the 20th century, he opposed not only to the ideas of Arians but also to the teaching of Fotinus, bishop of Sirmium. Chromatius was a very zealous fighter and he practically succeeded to uproot all heretical ideas in his diocese. The academia usually sees him as an anti-Arian theologian. After the Council of Constantinople (381), the Arian heresy seemed to be abated, but Chromatius said in one of his Tractatus, “Cuius (sc. Arii) discipuli hodieque oues Dei fallere ac decipere conantur per aliquantas ecclesias, sed iamdudum, magistro perfidiae prodito, discipuli latere non possunt”; it is evident that, the followers of Arius could still be found (with the mentioning of “hodie”, i.e. today) in the area of Aquileia, meanwhile one must not neglect the presence of the followers of Fotinus of Sirmium. The first part of my conference paper would be a general presentation of the religious situation in Aquileia at the time where Chromatius served as the local bishop; thus I will proceed with an in-depth reading on several passages of the Aquilerian bishop’s sermons (Sermones and Tractatus), in order to show the impact of the those heresies on his works and to identity his theological arguments against them. Among those teachings, there is the “unconquerable faith (invicta fide)”, which led to the surmounting (suppression) of heresies.

scholarly journals Tree-ring radiocarbon reveals reduced solar activity during Younger Dryas cooling

2020 ◽  
Author(s):  
Adam Sookdeo ◽  
Bernd Kromer ◽  
Florian Adolphi ◽  
Jürg Beer ◽  
Nicolas Brehm ◽  
...  
Keyword(s):  
Solar Activity ◽  
Tree Ring ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Core ◽  
Younger Dryas ◽  
Ice Age ◽  
The North ◽  
Long Duration ◽  
Clear Sign

<p>The Younger Dryas stadial (YD) was a return to glacial-like conditions in the North Atlantic region that interrupted deglacial warming around 12900 cal BP (before 1950 AD). Terrestrial and marine records suggest this event was initiated by the interruption of deep-water formation arising from North American freshwater runoff, but the causes of the millennia-long duration remain unclear. To investigate the solar activity, a possible YD driver, we exploit the cosmic production signals of tree-ring radiocarbon (<sup>14</sup>C) and ice-core beryllium-10 (<sup>10</sup>Be). Here we present the highest temporally resolved dataset of <sup>14</sup>C measurements (n = 1558) derived from European tree rings that have been accurately extended back to 14226 cal BP (±8, 2-σ), allowing precise alignment of ice-core records across this period. We identify a substantial increase in <sup>14</sup>C and <sup>10</sup>Be production starting at 12780 cal BP is comparable in magnitude to the historic Little Ice Age, being a clear sign of grand solar minima. We hypothesize the timing of the grand solar minima provides a significant amplifying factor leading to the harsh sustained glacial-like conditions seen in the YD.</p>

West Asian climate during the last millennium according to the EC-Earth model

2020 ◽  
Vol 57 (1) ◽  
pp. 102-113
Author(s):  
M.P. Karami ◽  
M. Mohtadi ◽  
Q. Zhang ◽  
T. Koenigk
Keyword(s):  
Decadal Variability ◽  
Ice Age ◽  
Earth Model ◽  
Precipitation Trend ◽  
Last Millennium ◽  
Climate Trends ◽  
The Caspian Sea ◽  
Internal Climate Variability ◽  
The North ◽  
The Impact

West Asia is one of the most vulnerable regions to ongoing climate change but has been poorly investigated. Therefore, it is crucial to understand the impact of anthropogenic greenhouse gas, natural forcing, and internal climate variability on temperature and rainfall in this region. In this study, we focus on the climate of West Asia during the last millennium by using a transient simulation of the global earth system model EC-Earth (v3.1). The model performs well in terms of present-day temperature and precipitation patterns and their regional averages. Time series of yearly-mean precipitation and temperature of West Asia show that precipitation increases until the start of the Little Ice Age (1450–1850 CE) and subsequently decreases, whereas temperature shows a cooling trend during the entire last millennium. We first discuss the model output data for climate trends during two periods, 850–1450 CE and 1450–1850 CE. In 850–1450 CE, the largest wetting trend occurred in the eastern regions to the north of the Persian Gulf because of a westward shift of the Indian precipitation core and more moisture transport from the Arabian Sea. The precipitation trend in 1450–1850 CE had a different pattern with a drying trend in the west of the Caspian Sea and overall getting less wet compared with the first period. Temperature showed cooling trends for both periods with the largest values happening in the northern regions. The North Atlantic sea surface temperature cooling and the subsequent change in atmospheric circulation played a role in the wetting and cooling of West Asia. In the second part of the study, we remove the trends and discuss the multi-decadal variability of West Asian climate. It was found that Atlantic multi-decadal and Pacific decadal oscillations strongly contributed to West Asian temperature variability. For West Asian precipitation variability, we found remote connections with the Nordic seas and tropical Pacific Ocean.

Holocene Glacial and Tree-Line Variations in the White River Valley and Skolai Pass, Alaska and Yukon Territory

1977 ◽  
Vol 7 (1) ◽  
pp. 63-111 ◽  
Author(s):  
George H. Denton ◽  
Wibjörn Karlén
Keyword(s):  
20Th Century ◽  
Little Ice Age ◽  
Yukon Territory ◽  
Summer Temperature ◽  
River Valley ◽  
Ice Age ◽  
The Arctic ◽  
Tree Line ◽  
White River ◽  
Glacier Recession

Complex glacier and tree-line fluctuations in the White River valley on the northern flank of the St. Elias and Wrangell Mountains in southern Alaska and Yukon Territory are recognized by detailed moraine maps and drift stratigraphy, and are dated by dendrochronology, lichenometry,14C ages, and stratigraphic relations of drift to the eastern (123014C yr BP) and northern (198014C yr BP) lobes of the White River Ash. The results show two major intervals of expansion, one concurrent with the well-known and widespread Little Ice Age and the other dated between 2900 and 210014C yr BP, with a culmination about 2600 and 280014C yr BP. Here, the ages of Little Ice Age moraines suggest fluctuating glacier expansion between ad 1500 and the early 20th century. Much of the 20th century has experienced glacier recession, but probably it would be premature to declare the Little Ice Age over. The complex moraine systems of the older expansion interval lie immediately downvalley from Little Ice Age moraines, suggesting that the two expansion intervals represent similar events in the Holocene, and hence that the Little Ice Age is not unique. Another very short-lived advance occurred about 1230 to 105014C yr BP. Spruce immigrated into the valley to a minimum altitude of 3500 ft (1067 m), about 600 ft (183 m) below the current spruce tree line of 4100 ft (1250 m), at least by 802014C yr BP. Subsequent intervals of high tree line were in accord with glacier recession; in fact, several spruce-wood deposits above current tree line occur bedded between Holocene tills. High deposits of fossil wood range up to 76 m above present tree line and are dated at about 5250, 3600 to 3000, and 2100 to 123014C yr BP. St. Elias glacial and tree-line fluctuations, which probably are controlled predominantly by summer temperature and by length of the growing and ablation seasons, correlate closely with a detailed Holocene tree-ring curve from California, suggesting a degree of synchronism of Holocene summer-temperature changes between the two areas. This synchronism is strengthened by comparison with the glacier record from British Columbia and Mt. Rainier. Likewise, broad synchronism of Holocene events exists across the Arctic between the St. Elias Mountains and Swedish Lappland. Finally, two sequences from the Southern Hemisphere show similar records, in so far as dating allows. Hence, we believe that a preliminary case can be made for broad synchronism of Holocene climatic fluctuations in several regions, although further data are needed and several areas, particularly Colorado and Baffin Island, show major differences in the regional pattern.

scholarly journals Simulated retreat of Jakobshavn Isbræ since the Little Ice Age controlled by geometry

2018 ◽  
Vol 12 (7) ◽  
pp. 2249-2266 ◽  
Author(s):  
Nadine Steiger ◽  
Kerim H. Nisancioglu ◽  
Henning Åkesson ◽  
Basile de Fleurian ◽  
Faezeh M. Nick
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Climate Forcing ◽  
Relative Role ◽  
Regional Warming ◽  
History Of ◽  
The Impact ◽  
Term Response

Abstract. Rapid retreat of Greenland's marine-terminating glaciers coincides with regional warming trends, which have broadly been used to explain these rapid changes. However, outlet glaciers within similar climate regimes experience widely contrasting retreat patterns, suggesting that the local fjord geometry could be an important additional factor. To assess the relative role of climate and fjord geometry, we use the retreat history of Jakobshavn Isbræ, West Greenland, since the Little Ice Age (LIA) maximum in 1850 as a baseline for the parameterization of a depth- and width-integrated ice flow model. The impact of fjord geometry is isolated by using a linearly increasing climate forcing since the LIA and testing a range of simplified geometries. We find that the total length of retreat is determined by external factors – such as hydrofracturing, submarine melt and buttressing by sea ice – whereas the retreat pattern is governed by the fjord geometry. Narrow and shallow areas provide pinning points and cause delayed but rapid retreat without additional climate warming, after decades of grounding line stability. We suggest that these geometric pinning points may be used to locate potential sites for moraine formation and to predict the long-term response of the glacier. As a consequence, to assess the impact of climate on the retreat history of a glacier, each system has to be analyzed with knowledge of its historic retreat and the local fjord geometry.

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