Late-Quaternary summer temperature changes in the northern-European tree-line region

2008 ◽  
Vol 69 (03) ◽  
pp. 404-412 ◽  
Author(s):  
Heikki Seppä ◽  
Glen M. MacDonald ◽  
H. John B. Birks ◽  
Bruce R. Gervais ◽  
Jeffrey A. Snyder
Keyword(s):  
Kola Peninsula ◽  
Younger Dryas ◽  
Summer Temperature ◽  
The Arctic ◽  
Fossil Pollen ◽  
Tree Line ◽  
Temperature Changes ◽  
The Holocene ◽  
Northern European ◽  
Line Region

We present two new quantitative July mean temperature (Tjul) reconstructions from the Arctic tree-line region in the Kola Peninsula in north-western Russia. The reconstructions are based on fossil pollen records and cover the Younger Dryas stadial and the Holocene. The inferred temperatures are less reliable during the Younger Dryas because of the poorer fit between the fossil pollen samples and the modern samples in the calibration set than during the Holocene. The results suggest that the Younger Dryas Tjulin the region was 8.0–10.0°C, being 2.0–3.0°C lower than at present. The Holocene summer temperature maximum dates to 7500–6500 cal yr BP, with Tjulabout 1.5°C higher than at present. These new records contribute to our understanding of summer temperature changes along the northern-European tree-line region. The Holocene trends are consistent in most of the independent records from the Fennoscandian–Kola tree-line region, with the beginning of the Holocene thermal maximum no sooner than at about 8000 cal yr BP. In the few existing temperature-related records farther east in the Russian Arctic tree line, the period of highest summer temperature begins already at about 10,000 cal yr BP. This difference may reflect the strong influence of the Atlantic coastal current on the atmospheric circulation pattern and the thermal behaviour of the tree-line region on the Atlantic seaboard, and the more direct influence of the summer solar insolation on summer temperature in the region east of the Kola Peninsula.

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 Paleosols of the Interglacial Climates in Canada

2007 ◽  
Vol 44 (3) ◽  
pp. 363-374 ◽  
Author(s):  
Charles Tarnocai
Keyword(s):  
Forest Soils ◽  
The Arctic ◽  
Interglacial Period ◽  
Mean Annual Temperature ◽  
Tree Line ◽  
Climatic Parameters ◽  
The Holocene ◽  
Paleoclimatic Reconstruction ◽  
Soil Features ◽  
The Mean

ABSTRACTAlthough paleosols are useful indicators of paleoclimates. it is first necessary to establish the relationships between the northern limits of the various contemporary soils and the pertinent climatic parameters. It is then necessary to determine the age of the various paleosols and, if possible, their northern limits. Comparison of the distribution and northern limits of the contemporary soils with the distribution and northern limits of the analogous paleosols then permits the reconstruction of the paleoenvironments. For the purposes of comparison the mean annual temperature of the Old Crow area during the Pliocene epoch was also determined (about 4°C) even though this was not an interglacial period. It was found that during the pre-lllinoian interglacial periods the central Yukon had a mean annual temperature of about 7°C while during the Sangamonian interglacial period it had a mean annual temperature of about - 3°C. During the Holocene epoch, the current interglacial period, the climate has been similar to or only slightly cooler than that existing during the Sangamonian interglacial period. The fluctuating position of the arctic tree line (and associated forest soils) during the Holocene epoch, however, indicates that the climate has also been fluctuating during this time. The paleoclimatic reconstruction presented in this paper also relies heavily on both diagnostic soil features and the soil development during the various interglacial periods.

Holocene tree line, permafrost, and climate dynamics in the Nenets Region, East European Arctic

2004 ◽  
Vol 41 (10) ◽  
pp. 1141-1158 ◽  
Author(s):  
Seija Kultti ◽  
Pirita Oksanen ◽  
Minna Väliranta
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
The Arctic ◽  
Tree Line ◽  
The Holocene ◽  
East European ◽  
Summer Temperatures ◽  
European Arctic ◽  
Peat Profile ◽  
Lake Core

Pollen, stomata, and macrofossils in a lake core with a basal date of 9700 14C BP were used to reconstruct past changes in climate and vegetation in the arctic tree line area, northeast European Russia. A palsa peat profile was investigated to establish a chronology of mire initiation and permafrost development during the Holocene. Macrofossils show that tree birch was present in the study area at the beginning of the Holocene and stands of spruce became established shortly thereafter. However, pollen evidence suggests that almost 400 years passed before the area was occupied by a mixed spruce–birch forest, which lasted until ca. 5000 BP. Subsequently, the area reverted to forest–tundra. Paludification began ca. 9000 BP continuing at least until 5700 BP. The conditions were permafrost-free at least until 4500 BP. The latest permafrost aggradation phase is dated to the Little Ice Age. We interpret summer temperatures to have been ca. 3–4 °C higher between ca. 8900 and 5500 BP than at present, and the lowest temperature regime of the Holocene to have occurred between 2700 and 2100 BP.

scholarly journals Spatially Continuous Land-Cover Reconstructions Through the Holocene in Southern Sweden

Ecosystems ◽  
2021 ◽  
Author(s):  
Robert O’Dwyer ◽  
Laurent Marquer ◽  
Anna-Kari Trondman ◽  
Anna Maria Jönsson
Keyword(s):  
Land Cover ◽  
Regional Scale ◽  
Coniferous Forest ◽  
Reconstruction Algorithm ◽  
Fossil Pollen ◽  
Conifer Forest ◽  
Southern Sweden ◽  
The Holocene ◽  
Simple Kriging ◽  
Pollen Records

AbstractClimate change and human activities influence the development of ecosystems, with human demand of ecosystem services altering both land use and land cover. Fossil pollen records provide time series of vegetation characteristics, and the aim of this study was to create spatially continuous reconstructions of land cover through the Holocene in southern Sweden. The Landscape Reconstruction Algorithm (LRA) was applied to obtain quantitative reconstructions of pollen-based vegetation cover at local scales, accounting for pollen production, dispersal, and deposition mechanisms. Pollen-based local vegetation estimates were produced from 41 fossil pollen records available for the region. A comparison of 17 interpolation methods was made and evaluated by comparing with current land cover. Simple kriging with cokriging using elevation was selected to interpolate the local characteristics of past land cover, to generate more detailed reconstructions of trends and degree of variability in time and space than previous studies based on pollen data representing the regional scale. Since the Mesolithic, two main processes have acted to reshape the land cover of southern Sweden, originally mostly covered by broad-leaved forests. The natural distribution limit of coniferous forest has moved southward during periods with colder climate and retracted northward during warmer periods, and human expansion in the area and agrotechnological developments has led to a gradually more open landscape, reaching maximum openness at the beginning of the 20th century. The recent intensification of agriculture has led to abandonment of less fertile agricultural fields and afforestation with conifer forest.

Identification of Younger Dryas outburst flood path from Lake Agassiz to the Arctic Ocean

Nature ◽  
2010 ◽  
Vol 464 (7289) ◽  
pp. 740-743 ◽  
Author(s):  
Julian B. Murton ◽  
Mark D. Bateman ◽  
Scott R. Dallimore ◽  
James T. Teller ◽  
Zhirong Yang
Keyword(s):  
Arctic Ocean ◽  
Younger Dryas ◽  
The Arctic ◽  
Outburst Flood ◽  
Lake Agassiz ◽  
The Arctic Ocean

scholarly journals Neoglacial history of Robson Glacier, British Columbia

2017 ◽  
Vol 54 (11) ◽  
pp. 1153-1164 ◽  
Author(s):  
B.H. Luckman ◽  
M.H. Masiokas ◽  
K. Nicolussi
Keyword(s):  
British Columbia ◽  
Little Ice Age ◽  
Ice Age ◽  
Tree Line ◽  
Canadian Rockies ◽  
The Holocene ◽  
Forest Sites ◽  
History Of ◽  
Subfossil Wood ◽  
Glacier Advance

As glaciers in the Canadian Rockies recede, glacier forefields continue to yield subfossil wood from sites overridden by these glaciers during the Holocene. Robson Glacier in British Columbia formerly extended below tree line, and recession over the last century has progressively revealed a number of buried forest sites that are providing one of the more complete records of glacier history in the Canadian Rockies during the latter half of the Holocene. The glacier was advancing ca. 5.5 km upvalley of the Little Ice Age terminus ca. 5.26 cal ka BP, at sites ca. 2 km upvalley ca. 4.02 cal ka BP and ca. 3.55 cal ka BP, and 0.5–1 km upvalley between 1140 and 1350 A.D. There is also limited evidence based on detrital wood of an additional period of glacier advance ca. 3.24 cal ka BP. This record is more similar to glacier histories further west in British Columbia than elsewhere in the Rockies and provides the first evidence for a post-Hypsithermal glacier advance at ca. 5.26 cal ka BP in the Rockies. The utilization of the wiggle-matching approach using multiple 14C dates from sample locations determined by dendrochronological analyses enabled the recognition of 14C outliers and an increase in the precision and accuracy of the dating of glacier advances.

scholarly journals Ring-widths of Abies at tree-line ecotone reveal three centuries of early winter season temperature changes in Yunnan, China

2020 ◽  
Vol 55 (3-4) ◽  
pp. 945-959 ◽  
Author(s):  
Yingfeng Bi ◽  
Whitney Cory ◽  
Zenxin Fan ◽  
Jingchao Yang ◽  
Zhikun Wu ◽  
...  
Keyword(s):  
Winter Season ◽  
Early Winter ◽  
Tree Line ◽  
Temperature Changes

scholarly journals New species of Scolelepis (Polychaeta, Spionidae) from the Norwegian coast and Barents Sea with a brief review of the genus

2015 ◽  
Vol 35 ◽  
pp. 9 ◽  
Author(s):  
Andrey Sikorski ◽  
Lyudmila Pavlova
Keyword(s):  
New Species ◽  
Kola Peninsula ◽  
Climate Warming ◽  
Barents Sea ◽  
Identification Key ◽  
The Arctic ◽  
Atlantic Sector ◽  
Norwegian Coast ◽  
The Barents Sea

<p>The species <em>Scolelepis finmarchicus</em> sp. nov. is described from the Norwegian and Barents Seas along the northern Norwegian coast and Kola peninsula. The occurrence of this species in the Kola Bay could be seen as a sign of climate warming in the area. Taxonomic issues existing in the genus <em>Scolelepis</em> within the area along the Norwegian coast and in the Barents Sea are briefly touched upon. Seven species belonging to <em>Scolelepis</em> have recently been recorded from the Atlantic sector of the Arctic. <em>Scolelepis</em> (<em>S</em>.) <em>matsugae</em> Sikorski, 1994 is newly synonymized with <em>S</em>. (<em>S</em>.) <em>laonicola</em> (Tzetlin, 1985). This article provides a brief review of <em>Scolelepis</em> together with an identification key for the genus from the Atlantic sector of the Arctic</p>

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