Multi-proxy record of postglacial environmental change, south-central Melville Island, Northwest Territories, Canada

2010 ◽  
Vol 73 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Matthew Peros ◽  
Konrad Gajewski ◽  
Tara Paull ◽  
Rebecca Ravindra ◽  
Brandi Podritske
Keyword(s):  
Late Holocene ◽  
High Arctic ◽  
The Arctic ◽  
Dry Period ◽  
Proxy Record ◽  
Holocene Thermal Maximum ◽  
The Past ◽  
Climate Reconstructions ◽  
South Central ◽  
Thermal Maximum

A sediment core from Lake BC01 (75"10.945?N, 111"55.181?W, 225"m asl) on south-central Melville Island, NWT, Canada, provides the first continuous postglacial environmental record for the region. Fossil pollen results indicate that the postglacial landscape was dominated by Poaceae andSalix, typical of a High Arctic plant community, whereas the Arctic herbOxyriaunderwent a gradual increase during the late Holocene. Pollen-based climate reconstructions suggests the presence of a cold and dry period ~12,000"cal yr BP, possibly representing the Younger Dryas, followed by warmer and wetter conditions from 11,000 to 5000"cal yr BP, likely reflective of the Holocene Thermal Maximum. The climate then underwent a gradual cooling and drying from 5000"cal yr BP to the present, suggesting a late Holocene neoglacial cooling. Diatom preservation was poor prior to 5000"cal yr BP, when conditions were warmest, suggesting that diatom dissolution may in part be climatically controlled. Diatom concentrations were highest ~4500"cal yr BP but then decreased substantially by 3500"cal yr BP and remained low before recovering slightly in the 20th century. An abrupt warming occurred during the past 70 yr at the site, although the magnitude of this warming did not exceed that of the early Holocene.

scholarly journals Mid-Holocene Northern Hemisphere warming driven by Arctic amplification

2019 ◽  
Vol 5 (12) ◽  
pp. eaax8203 ◽  
Author(s):  
Hyo-Seok Park ◽  
Seong-Joong Kim ◽  
Andrew L. Stewart ◽  
Seok-Woo Son ◽  
Kyong-Hwan Seo
Keyword(s):  
Sea Ice ◽  
Northern Hemisphere ◽  
High Latitude ◽  
Climate Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Arctic Amplification ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum

The Holocene thermal maximum was characterized by strong summer solar heating that substantially increased the summertime temperature relative to preindustrial climate. However, the summer warming was compensated by weaker winter insolation, and the annual mean temperature of the Holocene thermal maximum remains ambiguous. Using multimodel mid-Holocene simulations, we show that the annual mean Northern Hemisphere temperature is strongly correlated with the degree of Arctic amplification and sea ice loss. Additional model experiments show that the summer Arctic sea ice loss persists into winter and increases the mid- and high-latitude temperatures. These results are evaluated against four proxy datasets to verify that the annual mean northern high-latitude temperature during the mid-Holocene was warmer than the preindustrial climate, because of the seasonally rectified temperature increase driven by the Arctic amplification. This study offers a resolution to the “Holocene temperature conundrum”, a well-known discrepancy between paleo-proxies and climate model simulations of Holocene thermal maximum.

Rapid neoglaciation on Ellesmere Island promoted by enhanced summer snowfall in a transient climate model simulation of the middle-late-Holocene

The Holocene ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 1474-1480
Author(s):  
Stephen J Vavrus ◽  
Feng He ◽  
John E Kutzbach ◽  
William F Ruddiman
Keyword(s):  
Snow Depth ◽  
Late Holocene ◽  
Climate Model ◽  
Model Simulation ◽  
Short Circuit ◽  
Ellesmere Island ◽  
The Arctic ◽  
Holocene Thermal Maximum ◽  
Model Driven ◽  
The Arctic Oscillation

Arctic neoglaciation following the Holocene Thermal Maximum is an important feature of late-Holocene climate. We investigated this phenomenon using a transient 6000-year simulation with the CESM-CAM5 climate model driven by orbital forcing, greenhouse gas concentrations, and a land use reconstruction. During the first three millennia analyzed here (6–3 ka), mean Arctic snow depth increases, despite enhanced greenhouse forcing. Superimposed on this secular trend is a very abrupt increase in snow depth between 5 and 4.9 ka on Ellesmere Island and the Greenland coasts, in rough agreement with the timing of observed neoglaciation in the region. This transition is especially extreme on Ellesmere Island, where end-of-summer snow coverage jumps from nearly 0 to virtually 100% in 1 year, and snow depth increases to the model’s imposed maximum within 15 years. This climatic shift involves more than the Milankovitch-based expectation of cooler summers causing less snow melt. Coincident with the onset of the cold regime are two consecutive summers with heavy snowfall on Ellesmere Island that help to short-circuit the normal seasonal melt cycle. These heavy snow seasons are caused by synoptic-scale, cyclonic circulation anomalies over the Arctic Ocean and Canadian Archipelago, including an extremely positive phase of the Arctic Oscillation. Our study reveals that a climate model can produce sudden climatic transitions in this region prone to glacial inception and exceptional variability, due to a dynamic mechanism (more summer snowfall induced by an extreme circulation anomaly) that augments the traditional Milankovitch thermodynamic explanation of orbitally induced glacier development.

Dwarf tundra shrubs growth as a proxy for late Holocene climate change

2015 ◽  
Vol 5 (2) ◽  
pp. 185-199 ◽  
Author(s):  
Jiří Lehejček
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
The Arctic ◽  
Detailed Knowledge ◽  
Field Collection ◽  
The Past ◽  
Growth Increments ◽  
Research Designs ◽  
Summer Temperatures ◽  
The Relationship

The Arctic is the most sensitive zone to climate changes and the impacts are reflected in local ecosystems. In order to extract information of the past from proxy archives the detailed knowledge of such archive is crucial. The paper summarizes modern approaches of tundra dwarf shrub research for the purposes of paleoclimatology. Dwarf tundra shrubs as still relatively untapped archive are believed to contain valuable proxy data in their annual growth increments. Field sampling, and laboratory work are reviewed in detail. Constraints of dwarf tundra shrub research are discussed as well. The relationship between climate and growth is addressed to find a link between them depending on location and species. Majority of investigations found the strongest relationship between summer temperatures and ring widths, although exceptions are not rare. Dwarf tundra shrubs can fully serve as valuable proxy archive only if those are understood. Finally, the factors influencing the length of dwarf tundra shrub life are studied in order to sample the oldest living individuals in the field. Despite the field collection should aim to sample various sizes and ages of plants to make the dataset robust, the longest living individuals which are important to prolong chronologies are usually inhabiting rather nutrient poor and undisturbed sites close to their survival limits. The paper indicates the most suitable dwarf tundra shrub research designs for the purposes of paleoclimatology. As such it can help to harvest the benefits of dendrochronology from the vast and new territories.

Northward oceanic heat transport in the main branch of the Norwegian Atlantic Current over the late Holocene

The Holocene ◽  
2017 ◽  
Vol 27 (7) ◽  
pp. 1034-1044 ◽  
Author(s):  
Andrea D Tegzes ◽  
Eystein Jansen ◽  
Torbjørn Lorentzen ◽  
Richard J Telford
Keyword(s):  
Heat Transport ◽  
Time Scales ◽  
Late Holocene ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Upper Ocean ◽  
Oceanic Heat Transport ◽  
The Past ◽  
Norwegian Margin ◽  
Atlantic Current

The Norwegian Atlantic Current represents the northernmost reaches of the (sub)surface limb of the Atlantic Meridional Overturning Circulation. Its shelf-edge branch, the Norwegian Atlantic Slope Current (NwASC), is of particular interest as it seems to be the main conduit for advected heat towards the Arctic. The objective of this study was to investigate northward oceanic heat transport in the NwASC on longer, geologically meaningful time scales. To this end, we reconstructed variations in the strength of the NwASC over the late Holocene using the sortable-silt method. We then analysed the statistical relationship between our palaeo-flow reconstructions and published upper-ocean hydrography proxy records from the same location on the mid-Norwegian Margin. Our sortable-silt time series show prominent multi-decadal to multi-centennial variability, but no clear long-term trend over the past 4200 years. These records we thus interpret to represent perturbations in a relatively stable late-Holocene mean flow. Our in-depth statistical analysis indicates that upper-ocean temperatures at the mid-Norwegian Margin may have varied independently from the strength of the NwASC on multi-decadal to multi-centennial time scales over the past few millennia.

Modern warming exceeds sea surface temperatures of the Holocene Thermal Maximum in Kongsfjorden, Svalbard

2021 ◽  
Author(s):  
Harikrishnan Guruvayoorappan ◽  
Arto Miettinen ◽  
Dmitry Divine ◽  
Rahul Mohan
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Sea Surface ◽  
The Arctic ◽  
Sea Surface Temperatures ◽  
Surface Conditions ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
Ice Conditions

<p>Certain past climatic events act as an analogue for future climatic conditions. The Holocene epoch featured a number of climatic variations of which Holocene Thermal Maximum (HTM) stands out as a recognizable phenomenon, especially in the North Atlantic and the Arctic. Similar to modern warming, HTM in Svalbard recorded extreme warmth along with intense deglaciation and sea ice retreat. Therefore, predictions of future climate using HTM depends on understanding the changes in interactions between ocean, sea ice, and atmospheric conditions. While many studies exist on this period, only few have reconstructed ocean surface conditions in the Arctic at high resolution. Here we present the first diatom-based high-resolution quantitative reconstruction of sea surface conditions from Kongsfjorden, Svalbard covering the period of ca. 10.5 to 7.5 cal. kyr BP. Our reconstructions of sea surface temperature (SST) and sea ice conditions are based on diatom microfossil records from a 454 cm long marine sediment core from Kongsfjorden, Svalbard. The section from 454 to 300 cm was used for reconstructions owing to the lack of availability of diatom microfossils. Owing to their high sensitivity towards SST and sea ice, diatoms act as excellent proxies of these environmental conditions in the past. The SST record from Kongsfjorden reveals moderately warm open water conditions and highly variable sea ice conditions during the HTM. The SST achieves maximum values during the early Holocene insolation maxima ca. 10.5 to 7.5 cal. kyr BP, followed by a slow cooling trend simultaneously with the decreasing insolation intensity. Our results emphasize the regional heterogeneity observed in ocean surfaces during the HTM and how modern warming in the study area has already reached sea surface temperatures comparable to the HTM. </p>

Development of Surficial Deposits on Belyi Island (Kara Sea) during the Last 40,000 Years

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1439-1455 ◽  
Author(s):  
A Yurtaev ◽  
A Alexandrovskiy ◽  
V Skripkin ◽  
E Zazovskaya ◽  
A Dolgikh
Keyword(s):  
Late Holocene ◽  
Late Glacial ◽  
Time Interval ◽  
Warm Climate ◽  
Significant Group ◽  
Climate Conditions ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
Surficial Deposits ◽  
Middle And Late Holocene

ABSTRACTA series of radiocarbon (14C) dates of peat and other materials, containing organic matter, were obtained from Belyi Island. We have identified a large group of dates associates with MIS 1, as well as a significant group of dates associated with the Kargin (MIS 3) period (40–31 ka cal BP). A large number of dates from the Late Glacial period and from the Early Holocene (MIS 1—ca. 14–9 ka cal BP) point to this time interval being associated with warm climate conditions (the Holocene thermal maximum). The climate cooled off significantly during the Middle and Late Holocene, and the intensity of peat accumulation declined. The dates from the MIS 2 period are missing, due to the conditions of this period being extremely unfavorable for the accumulation of peat, as well as of other materials suitable for 14C dating.

Holocene sediments from a coastal lake on northern Devon Island, Nunavut, Canada

2013 ◽  
Vol 50 (5) ◽  
pp. 564-575 ◽  
Author(s):  
Colin J. Courtney Mustaphi ◽  
Konrad Gajewski
Keyword(s):  
Sediment Cores ◽  
Sediment Accumulation ◽  
Laminated Sediments ◽  
The Arctic ◽  
Coastal Lake ◽  
Holocene Thermal Maximum ◽  
Devon Island ◽  
Sediment Stratigraphy ◽  
Thermal Maximum ◽  
History Of

Sediment cores from Lake DV09, northern Devon Island, Nunavut, Canada (75°34′34″N, 89°18′55″W), were studied to reconstruct the lake ontogeny through analysis and interpretation of the sediment stratigraphy. The lake was uplifted from marine inundation ∼7600 cal BP. After a millennium of rapid sediment accumulation, which coincided with the Holocene Thermal Maximum in the region, accumulation rates decreased over the past 6000 years as the Arctic became colder. This resulted in the deposition of very fine laminae that were interpreted as varves. The uppermost laminated sediments provided a ∼1600 year history of annual sediment transport and deposition into the lake. During periods of warmer temperatures, such as between 6000 and 7500 cal BP and during the Medieval Climate Anomaly (∼950–1300 CE; CE, Christian Era), hydroclimatic and permafrost slope processes increased sedimentation rates into the basin.

scholarly journals Modeling the climatic implications and indicative senses of the Guliya δ<sup>18</sup>O-temperature proxy record to the ocean–atmosphere system during the past 130 ka

2013 ◽  
Vol 9 (2) ◽  
pp. 735-747 ◽  
Author(s):  
D. Xiao ◽  
P. Zhao ◽  
Y. Wang ◽  
X. Zhou
Keyword(s):  
Solar Radiation ◽  
North Atlantic ◽  
The Arctic ◽  
Proxy Record ◽  
The Past ◽  
The North ◽  
Incoming Solar Radiation ◽  
The North Atlantic ◽  
Temperature Proxy ◽  
Anomalous Pattern

Abstract. Using an intermediate-complexity UVic Earth System Climate Model (UVic Model), the geographical and seasonal implications and indicative senses of the Guliya temperature proxy found in the Guliya δ18O ice core record (hereinafter, the Guliya δ18O-temperature proxy record) are investigated under time-dependent orbital and CO2 forcings with an acceleration factor of 50 over the past 130 ka. The results reveal that the simulated August–September Guliya surface air temperature (SAT) reproduces the 21-ka precession and 43-ka obliquity cycles of the Guliya δ18O-temperature proxy record, showing an in-phase variation with the latter. Moreover, the Guliya δ18O-temperature proxy record may be also an indicator of the August–September Northern Hemispheric (NH) SAT. Corresponding to the difference between the extreme warm and cold phases of the precession cycle in the Guliya August–September SAT, there are two anomalous patterns in SAT and sea surface temperature (SST). The first anomalous pattern shows increases of SAT and SST toward the Arctic, which is possibly associated with an increase of the NH incoming solar radiation that is caused by the in-phase superposition between the precession and obliquity cycles. The second anomalous pattern shows increases of SAT and SST toward the equator, which is possibly due to a decrease of incoming solar radiation over the NH polar that results from the anti-phase counteraction between the precession and obliquity cycles. The summer (winter) Guliya and NH temperatures are higher (lower) in the warm phases of the August–September Guliya than in their cold phases. Moreover, in August–September, the Guliya SAT is closely related to the North Atlantic SST, in which the Guliya precipitation might act as a "bridge" linking the Guliya SAT and the North Atlantic SST.

A record of mid- and late Holocene paleohydroclimate from Lower Pahranagat Lake, southern Great Basin

2019 ◽  
Vol 92 (2) ◽  
pp. 352-364
Author(s):  
Kevin M. Theissen ◽  
Thomas A. Hickson ◽  
Ashley L. Brundrett ◽  
Sarah E. Horns ◽  
Matthew S. Lachniet
Keyword(s):  
Great Basin ◽  
Late Holocene ◽  
Fine Fraction ◽  
Total Inorganic Carbon ◽  
Dry Period ◽  
The Past ◽  
The North ◽  
Southern Nevada ◽  
Show Evidence ◽  
Hydroclimatic Variability

AbstractWe present a continuous, sediment core-based record of paleohydroclimate spanning ~5800 cal yr BP to recent from Lower Pahranagat Lake (LPAH), a shallow, alkaline lake in southern Nevada. We apply stable isotopes (δ18O and δ13C) from fine-fraction authigenic carbonate, which are sensitive recorders of hydroclimatic variability in this highly evaporative region. Additional geochemical proxies (total organic carbon, C/N, and total inorganic carbon) provide supporting information on paleoecological change in and around the lake. Our data suggest progressively wetter conditions starting at the later part of the middle Holocene and extending into the late Holocene (~5500–3350 cal yr BP) followed by a millennial-scale dry period from ~3150 to 1700 cal yr BP. This latter interval encompasses the ‘Late Holocene dry period’ (LHDP) reported by other investigators, and our data help refine the area affected in this episode. Our data also show evidence for a series of century-scale fluctuations in regional hydroclimate, including wet and dry intervals between 2350 and 1600 cal yr BP, and drier conditions over the past few centuries. Paleohydroclimate trends in the LPAH record show correspondence with those from the central Great Basin to the north, suggesting that both areas were subject to similar climatic forcings.

Sign in / Sign up

Export Citation Format

Share Document