scholarly journals Climate warming and vegetation response at the end of Heinrich event 1 (16 700–16 000 cal yr BP) in Europe south of the Alps

2012 ◽  
Vol 8 (3) ◽  
pp. 1615-1651 ◽  
Author(s):  
S. Samartin ◽  
O. Heiri ◽  
A. F. Lotter ◽  
W. Tinner
Keyword(s):  
Large Scale ◽  
Late Glacial ◽  
Northern Italy ◽  
Swiss Alps ◽  
Pollen Record ◽  
Heinrich Event ◽  
Air Temperatures ◽  
The Alps ◽  
Temperature Inference ◽  
Heinrich Event 1

Abstract. Chironomids preserved in a sediment core from Lago di Origlio (416 m a.s.l.), a lake in the foreland of the Southern Swiss Alps, allowed quantitative reconstruction of Late Glacial and early Holocene temperatures using a combined Swiss-Norwegian temperature inference model based on chironomid assemblages from 274 lakes. We reconstruct July air temperatures of ca. 10 °C between 17 300 and 16 000 cal yr BP, a rather abrupt warming to ca. 12.0 °C at ca. 16 500–16 000 cal yr BP, and a strong temperature increase at the transition to the Bølling/Allerød Interstadial with average temperatures of about 14 °C. During the Younger Dryas and earliest Holocene very similar temperatures are reconstructed as for the interstadial. The rather abrupt warming at 16 500–16 000 cal yr BP is consistent with sea-surface temperature as well as speleotherm records, which indicate a marked Pre-Bølling warming after the end of Heinrich event 1 in southern Europe and the Mediterranean Sea. The pollen record of Origlio and other sites from southern Switzerland and northern Italy indicate an early reforestation of the lowlands prior to the large-scale afforestation at the onset of the Bølling period at 14 700 cal yr BP in Central Europe. Our results suggest that these afforestation processes in the formerly glaciated areas of southern Switzerland and Northern Italy have been promoted by increasing temperatures.

scholarly journals Climate warming and vegetation response after Heinrich event 1 (16 700–16 000 cal yr BP) in Europe south of the Alps

2012 ◽  
Vol 8 (6) ◽  
pp. 1913-1927 ◽  
Author(s):  
S. Samartin ◽  
O. Heiri ◽  
A. F. Lotter ◽  
W. Tinner
Keyword(s):  
Large Scale ◽  
Late Glacial ◽  
Sensu Stricto ◽  
Northern Italy ◽  
Swiss Alps ◽  
Heinrich Event ◽  
Air Temperatures ◽  
Summer Temperatures ◽  
The Alps ◽  
Heinrich Event 1

Abstract. Chironomids preserved in a sediment core from Lago di Origlio (416 m a.s.l.), a lake in the foreland of the Southern Swiss Alps, allowed quantitative reconstruction of Late Glacial and Early Holocene summer temperatures using a combined Swiss–Norwegian temperature inference model based on chironomid assemblages from 274 lakes. We reconstruct July air temperatures of ca. 10 °C between 17 300 and 16 000 cal yr BP, a rather abrupt warming to ca. 12.0 °C at ca. 16 500–16 000 cal yr BP, and a strong temperature increase at the transition to the Bølling/Allerød interstadial with average temperatures of about 14 °C. During the Younger Dryas and earliest Holocene similar temperatures are reconstructed as for the interstadial. The rather abrupt warming at 16 500–16 000 cal yr BP is consistent with sea-surface temperature as well as speleothem records, which indicate a warming after the end of Heinrich event 1 (sensu stricto) and before the Bølling/Allerød interstadial in southern Europe and the Mediterranean Sea. Pollen records from Origlio and other sites in southern Switzerland and northern Italy indicate an early reforestation of the lowlands 2000–1500 yr prior to the large-scale afforestation of Central Europe at the onset of the Bølling/Allerød period at ca. 14 700–14 600 cal yr BP. Our results suggest that these early afforestation processes in the formerly glaciated areas of northern Italy and southern Switzerland have been promoted by increasing temperatures.

scholarly journals Local- and Regional-Scale Forcing of Glacier Mass Balance Changes in the Swiss Alps

2021 ◽  
Vol 13 (10) ◽  
pp. 1949
Author(s):  
Saeideh Gharehchahi ◽  
Thomas J. Ballinger ◽  
Jennifer L. R. Jensen ◽  
Anshuman Bhardwaj ◽  
Lydia Sam ◽  
...  
Keyword(s):  
Mass Balance ◽  
Large Scale ◽  
Regional Scale ◽  
Atlantic Multidecadal Oscillation ◽  
Swiss Alps ◽  
Glacier Mass Balance ◽  
Landsat Images ◽  
Air Temperatures ◽  
Lake Formation ◽  
The Impact

Glacier mass variations are climate indicators. Therefore, it is essential to examine both winter and summer mass balance variability over a long period of time to address climate-related ice mass fluctuations. In this study we analyze glacier mass balance components and hypsometric characteristics with respect to their interactions with local meteorological variables and remote large-scale atmospheric and oceanic patterns. The results show that all selected glaciers have lost their equilibrium condition in recent decades, with persistent negative annual mass balance trends and decreasing accumulation area ratios (AARs), accompanied by increasing air temperatures of ≥+0.45 °C decade−1. The controlling factor of annual mass balance is mainly attributed to summer mass losses, which are correlated with (warming) June to September air temperatures. In addition, the interannual variability of summer and winter mass balances is primarily associated to the Atlantic Multidecadal Oscillation (AMO), Greenland Blocking Index (GBI), and East Atlantic (EA) teleconnections. Although climate parameters are playing a significant role in determining the glacier mass balance in the region, the observed correlations and mass balance trends are in agreement with the hypsometric distribution and morphology of the glaciers. The analysis of decadal frontal retreat using Landsat images from 1984 to 2014 also supports the findings of this research, highlighting the impact of lake formation at terminus areas on rapid glacier retreat and mass loss in the Swiss Alps.

Climate change and ecosystem response in the northern Columbia River basin — A paleoenvironmental perspective

2008 ◽  
Vol 16 (NA) ◽  
pp. 113-140 ◽  
Author(s):  
Ian R. Walker ◽  
Marlow G. Pellatt
Keyword(s):  
River Basin ◽  
Large Scale ◽  
Columbia River ◽  
Late Glacial ◽  
Ecosystem Dynamics ◽  
Ice Age ◽  
Columbia River Basin ◽  
Past Century ◽  
Atmospheric Circulation Patterns ◽  
Air Temperatures

A comprehensive review of Holocene paleoenvironmental data has been prepared, providing the basis for evaluating natural variability in climate and ecosystem dynamics in the northern Columbia River basin. The paleoenvironmental record reveals four major climatic shifts and a number of less well-defined climatic changes throughout the Holocene. The major climate changes are (1) a cool or cold, late-glacial climate at the end of the last glaciation (>11 500 cal. year BP), (2) an interval of drought and maximum summer warmth during the early Holocene (ca. 10500 to 8000 cal. year BP), (3) a mid-Holocene trend towards a cooler, more moist climate (ca. 8000 to ca. 4000 cal. year BP), and (4) a relatively stable climate persisting from ca. 4000 cal. year BP until the arrival of European settlers. Air temperatures have warmed by about 1 °C over the past century. Minor climate events that are emerging as global in nature include Little Ice Age (1200–150 BP) conditions, and a late Holocene cool wet period (3500–2500 BP). These are observed in some study sites examined in this paper and may be related to large-scale cycles of 2800–2000 and 1500 years. A discussion of changing atmospheric circulation patterns, and the causes of long-term climatic change are included, together with a discussion of the implications of the paleoenvironmental record for understanding future climate, and the likely response of communities and ecosystems.

Calibrated long-term lacustrine paleoseismic records from Carinthia (Austria): implications for earthquake hazard in the south-eastern Alps

2021 ◽  
Author(s):  
Christoph Daxer ◽  
Marcel Ortler ◽  
Jyh-Jaan Steven Huang ◽  
Stefano Fabbri ◽  
Michael Hilbe ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Earthquake Hazard ◽  
Late Glacial ◽  
Eastern Alps ◽  
Swiss Alps ◽  
The South ◽  
Strong Earthquakes ◽  
Seismicity Pattern ◽  
South Eastern ◽  
The Alps

<p>In formerly glaciated intraplate settings with moderate seismicities, such as the Eastern Alps, recurrence intervals of strong earthquakes (M<sub>w </sub>>6) typically exceed the short time span of instrumental (~100 years) and historical (~1000 years) data. To assess the seismic hazards and draw conclusions about the role of postglacial isostatic rebound on earthquake recurrence in these regions, lakes have been increasingly used as natural seismographs over the last two decades.</p><p>We present paleoseismic records from three glacigenic lakes (Wörthersee, Millstätter See, and Klopeiner See) situated at the south-eastern rim of the Alps, Austria. This region, although located in an intraplate setting, has experienced several devastating historically and instrumentally recorded earthquakes with intensities ranging from V to IX (EMS-98) in our study area, e.g., in AD1348 (M<sub>w</sub> ~7; possibly the strongest historical earthquake in the Alps), AD1511 (Mw 6.9), AD1690 (Mw 6.5), AD1857 (Mw 5) and AD1976 (Mw 6.4).</p><p>The lakes were investigated with multibeam bathymetry and a very dense grid of reflection seismic profiles (~1.3, 3.5, and 8 kHz; 640 km in total). Numerous short (~1.5 m; ~80 cores) and long (~up to 14 m; 22 cores) sediment cores were retrieved from all lakes and their respective subbasins and were independently dated (varve counting in the last ~1000 years, radiocarbon, and <sup>210</sup>Pb/<sup>137</sup>Cs dating). This spatially and temporally high-resolution approach allows to construct a complete picture of the sedimentary imprint of strong earthquakes in these lakes.</p><p>The geophysical data image an archive of multiple simultaneous subaqueous landslides. In the sediment cores, which cover the last 7500 years in Millstätter See and reach back into the Late Glacial in Wörthersee and Klopeiner See, these landslides are represented as turbidite deposits (from mm to m-scale) interspersed in the partly finely laminated background sediments. By comparing the seismic intensities of the well-documented historical earthquakes to the spatial distribution of sedimentary imprint in the lakes, we revealed the earthquake recording thresholds (EQRT) of different depositional areas. Most of the sites record local intensities ≥VI. In shallow basins with low sedimentation rates, however, the EQRT is significantly higher, either solely recording the AD1348 event (VIII-IX) or showing no evidence of seismic shaking at all. Contrastingly, sites close to alluvial fans in Wörthersee also record the AD1857 and the AD1976 earthquakes (V½). Quantification of the earthquake-related deposits (e.g., cumulative turbidite thickness, percentage of depositional areas recording an event) shows a linear size-scaling relationship with the respective intensities. This provides us with a tool to constrain the local seismic intensity of prehistoric earthquakes.</p><p>Our data show that the AD1348 earthquake generated the strongest earthquake shaking in the study area for the entire Holocene. Generally, the seismicity peaked in the Late Glacial, around ~3.5 ka, and in the last ~1000 years, whereas the early- to mid-Holocene was a relatively calm period. Other paleo-earthquake studies from both the Fennoscandian Peninsula and the Swiss Alps show a similar seismicity pattern, suggesting that seismicity in the Alps is governed by postglacial rebound rather than tectonically induced stress.</p>

scholarly journals Past and future snowmelt trends in the Swiss Alps: the role of temperature and snowpack

2021 ◽  
Vol 165 (3-4) ◽  
Author(s):  
Maria Vorkauf ◽  
Christoph Marty ◽  
Ansgar Kahmen ◽  
Erika Hiltbrunner
Keyword(s):  
Snow Depth ◽  
Growing Season ◽  
High Elevation ◽  
Alpine Plants ◽  
Swiss Alps ◽  
Climate Change Scenarios ◽  
Freezing Damage ◽  
Strong Shift ◽  
Air Temperatures ◽  
Early Snowmelt

AbstractThe start of the growing season for alpine plants is primarily determined by the date of snowmelt. We analysed time series of snow depth at 23 manually operated and 15 automatic (IMIS) stations between 1055 and 2555 m asl in the Swiss Central Alps. Between 1958 and 2019, snowmelt dates occurred 2.8 ± 1.3 days earlier in the year per decade, with a strong shift towards earlier snowmelt dates during the late 1980s and early 1990s, but non-significant trends thereafter. Snowmelt dates at high-elevation automatic stations strongly correlated with snowmelt dates at lower-elevation manual stations. At all elevations, snowmelt dates strongly depended on spring air temperatures. More specifically, 44% of the variance in snowmelt dates was explained by the first day when a three-week running mean of daily air temperatures passed a 5 °C threshold. The mean winter snow depth accounted for 30% of the variance. We adopted the effects of air temperature and snowpack height to Swiss climate change scenarios to explore likely snowmelt trends throughout the twenty-first century. Under a high-emission scenario (RCP8.5), we simulated snowmelt dates to advance by 6 days per decade by the end of the century. By then, snowmelt dates could occur one month earlier than during the reference periods (1990–2019 and 2000–2019). Such early snowmelt may extend the alpine growing season by one third of its current duration while exposing alpine plants to shorter daylengths and adding a higher risk of freezing damage.

scholarly journals Holocene vegetation, fire and land use dynamics at Lake Svityaz, an agriculturally marginal site in northwestern Ukraine

2021 ◽  
Author(s):  
Christoph Schwörer ◽  
Erika Gobet ◽  
Jacqueline F. N. van Leeuwen ◽  
Sarah Bögli ◽  
Rachel Imboden ◽  
...  
Keyword(s):  
Bronze Age ◽  
Human Impact ◽  
Central Europe ◽  
Large Scale ◽  
Mixed Forest ◽  
Fire Risk ◽  
Late Glacial ◽  
Future Climate Change ◽  
Agricultural Activity ◽  
Fire Dynamics

AbstractObserving natural vegetation dynamics over the entire Holocene is difficult in Central Europe, due to pervasive and increasing human disturbance since the Neolithic. One strategy to minimize this limitation is to select a study site in an area that is marginal for agricultural activity. Here, we present a new sediment record from Lake Svityaz in northwestern Ukraine. We have reconstructed regional and local vegetation and fire dynamics since the Late Glacial using pollen, spores, macrofossils and charcoal. Boreal forest composed of Pinus sylvestris and Betula with continental Larix decidua and Pinus cembra established in the region around 13,450 cal bp, replacing an open, steppic landscape. The first temperate tree to expand was Ulmus at 11,800 cal bp, followed by Quercus, Fraxinus excelsior, Tilia and Corylus ca. 1,000 years later. Fire activity was highest during the Early Holocene, when summer solar insolation reached its maximum. Carpinus betulus and Fagus sylvatica established at ca. 6,000 cal bp, coinciding with the first indicators of agricultural activity in the region and a transient climatic shift to cooler and moister conditions. Human impact on the vegetation remained initially very low, only increasing during the Bronze Age, at ca. 3,400 cal bp. Large-scale forest openings and the establishment of the present-day cultural landscape occurred only during the past 500 years. The persistence of highly diverse mixed forest under absent or low anthropogenic disturbance until the Early Middle Ages corroborates the role of human impact in the impoverishment of temperate forests elsewhere in Central Europe. The preservation or reestablishment of such diverse forests may mitigate future climate change impacts, specifically by lowering fire risk under warmer and drier conditions.

Mollusc successions reveal northward postglacial shifts of Alpine species ranges (Bohemian Massif, Czech Republic)

The Holocene ◽  
2021 ◽  
pp. 095968362110116
Author(s):  
Lucie Juřičková ◽  
Jakub Menšík ◽  
Jitka Horáčková ◽  
Vojen Ložek
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Late Glacial ◽  
Glacial Refugia ◽  
Land Snails ◽  
Glacial Refugium ◽  
Local Climate ◽  
The Alps ◽  
Species Groups ◽  
Late Glacial And Holocene

The Alps are an important hotspot of species diversity and endemism, as well as a presumed glacial refugium of several species’ groups including land snails. The recent ranges of Alpine endemics are well known, but their fluctuations during the postglacial period mirroring local climate changes are understudied. By analysing five Late Glacial and Holocene mollusc successions from two areas in the southernmost part of the Bohemian Massif (Czech Republic) situated about 100 km north of the Alps, we reveal details of these fluctuations. The Alpine endemic rocky dweller Chilostoma achates had reached the southern part of the Bohemian Massif already in the Late Glacial and disappeared in the Mid-Holocene canopy forest optimum. On the contrary, the northern boundaries of Alpine canopy forest epigeic snails extended further north than today at the turn of the Middle and Late-Holocene, pointing to a more favourable forest microclimate. The earliest known occurrences of several temperate canopy forest central European species, especially Causa holosericea and Discus perspectivus, imply the role of different areas in the Alps as their glacial refugia.

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