scholarly journals Past, present and future biomes in Beringia: Comparison between simulations and pollen analysis

2018 ◽  
Author(s):  
Kazuyuki Saito ◽  
Amy Hendricks ◽  
John Walsh ◽  
Nancy Bigelow
Keyword(s):  
Cmip5 Models ◽  
Climate Data ◽  
Vegetation Model ◽  
Land Bridge ◽  
Study Region ◽  
Bering Land Bridge ◽  
Near Future ◽  
Warm Temperate ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Past, present and future biomes in Beringia, a region including Alaska and Eastern Russia, were simulated using an equilibrium vegetation model, BIOME4 and a statistical downscaling method in order to illustrate their geographical and temporal changes. Outputs form five CMIP5 models were utilized to represent the climate for four time periods, i.e., the Last Glacial Maximum (LGM; 21 ka), the mid-Holocene Optimum (6 ka), the modern period, and the near future (the end of this century under a RCP8.5 scenario). Present-day biome simulations were generally consistent with current vegetation observations in the study region. Pollen samples indicate that the Bering Land Bridge was covered almost entirely by cushionforb and graminoid tundra during the LGM, whereas the paleoclimate simulations show large across-model variations in this region. Three out of the five modelsʼ climate data produce evergreen and deciduous taiga at 21 ka in what is now southwestern Alaska and southeastern Bering continental shelf. The 6 ka simulations are in better agreement with pollen-based distributions of biomes. Future simulations show a general northward shift of biomes, including intrusions of cool and warm-temperate mixed, and cool coniferous forests above 60° N, especially in southwest Alaska.

scholarly journals A new terrestrial palaeoenvironmental record from the Bering Land Bridge and context for human dispersal

2018 ◽  
Vol 5 (6) ◽  
pp. 180145 ◽  
Author(s):  
Matthew J. Wooller ◽  
Émilie Saulnier-Talbot ◽  
Ben A. Potter ◽  
Soumaya Belmecheri ◽  
Nancy Bigelow ◽  
...  
Keyword(s):  
Climate Models ◽  
Environmental Changes ◽  
Land Bridge ◽  
Human Dispersal ◽  
South Central ◽  
Bering Land Bridge ◽  
Last Glaciation ◽  
Close Proximity ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Palaeoenvironmental records from the now-submerged Bering Land Bridge (BLB) covering the Last Glacial Maximum (LGM) to the present are needed to document changing environments and connections with the dispersal of humans into North America. Moreover, terrestrially based records of environmental changes are needed in close proximity to the re-establishment of circulation between Pacific and Atlantic Oceans following the end of the last glaciation to test palaeo-climate models for the high latitudes. We present the first terrestrial temperature and hydrologic reconstructions from the LGM to the present from the BLB's south-central margin. We find that the timing of the earliest unequivocal human dispersals into Alaska, based on archaeological evidence, corresponds with a shift to warmer/wetter conditions on the BLB between 14 700 and 13 500 years ago associated with the early Bølling/Allerød interstadial (BA). These environmental changes could have provided the impetus for eastward human dispersal at that time, from Western or central Beringia after a protracted human population standstill. Our data indicate substantial climate-induced environmental changes on the BLB since the LGM, which would potentially have had significant influences on megafaunal and human biogeography in the region.

scholarly journals Are Glacials Dry? Consequences for Paleoclimatology and for Greenhouse Warming

2017 ◽  
Vol 30 (17) ◽  
pp. 6593-6609 ◽  
Author(s):  
Jacob Scheff ◽  
Richard Seager ◽  
Haibo Liu ◽  
Sloan Coats
Keyword(s):  
Physical Property ◽  
Vegetation Changes ◽  
Cold Climates ◽  
Wetting And Drying ◽  
Plant Fossil ◽  
Future Warming ◽  
Near Future ◽  
The Last Glacial Maximum ◽  
Significant Conflict ◽  
The Last Glacial

Past cold climates are often thought to have been drier than today on land, which appears to conflict with certain recent studies projecting widespread terrestrial drying with near-future warming. However, other work has found that, over large portions of the continents, the conclusion of future drying versus wetting strongly depends on the physical property of interest. Here, it is shown that this also holds in simulations of the Last Glacial Maximum (LGM): the continents have generally wetter topsoils and higher values of common climate wetness metrics than in the preindustrial, as well as generally lower precipitation and ubiquitously lower photosynthesis (likely driven by the low CO2), with streamflow responses falling in between. Using a large existing global pollen and plant fossil compilation, it is also confirmed that LGM grasslands and open woodlands grew at many sites of present-day forest, seasonal forests at many sites of present-day rain forest, and so forth (116–144 sites out of 302), while changes in the opposite sense were very few (9–17 sites out of 302) and spatially confined. These vegetation changes resemble the model photosynthesis responses but not the hydroclimate responses, while published lake-level changes resemble the latter but not the former. Thus, confidence in both the model hydrologic and photosynthesis projections is increased, and there is no significant conflict. Instead, paleo- and modern climate researchers must carefully define “wetting” and “drying” and, in particular, should not assume hydrologic drying on the basis of vegetation decline alone or assume vegetation stress on the basis of declines in hydroclimatic indicators.

scholarly journals The southern coastal Beringian land bridge: cryptic refugium or pseudorefugium for woody plants during the Last Glacial Maximum?

2017 ◽  
Vol 44 (7) ◽  
pp. 1559-1571 ◽  
Author(s):  
Yue Wang ◽  
Peter D. Heintzman ◽  
Lee Newsom ◽  
Nancy H. Bigelow ◽  
Matthew J. Wooller ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Woody Plants ◽  
Glacial Maximum ◽  
Land Bridge ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Modelling the diversion of erratic boulders by the Valais Glacier during the last glacial maximum

2017 ◽  
Vol 63 (239) ◽  
pp. 487-498 ◽  
Author(s):  
GUILLAUME JOUVET ◽  
JULIEN SEGUINOT ◽  
SUSAN IVY-OCHS ◽  
MARTIN FUNK
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Balance Model ◽  
Precipitation Pattern ◽  
Climate Data ◽  
Surface Mass ◽  
Climate Conditions ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

ABSTRACTIn this study, a modelling approach was used to investigate the cause of the diversion of erratic boulders from Mont Blanc and southern Valais by the Valais Glacier to the Solothurn lobe during the Last Glacial Maximum (LGM). Using the Parallel Ice Sheet Model, we simulated the ice flow field during the LGM, and analyzed the trajectories taken by erratic boulders from areas with characteristic lithologies. The main difficulty in this exercise laid with the large uncertainties affecting the paleo climate forcing required as input for the surface mass-balance model. In order to mimic the prevailing climate conditions during the LGM, we applied different temperature offsets and regional precipitation corrections to present-day climate data, and selected the parametrizations, which yielded the best match between the modelled ice extent and the geomorphologically-based ice-margin reconstruction. After running a range of simulations with varying parameters, our results showed that only one parametrization allowed boulders to be diverted to the Solothurn lobe during the LGM. This precipitation pattern supports the existing theory of preferential southwesterly advection of moisture to the alps during the LGM, but also indicates strongly enhanced precipitation over the Mont Blanc massif and enhanced cooling over the Jura Mountains.

scholarly journals Supplemental Material: Climate of the Last Glacial Maximum on the western Olympic Peninsula based on insect paleoecology

2020 ◽  
Author(s):  
Allan Ashworth ◽  
et al.
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Fossil Insects ◽  
Climate Data ◽  
Model Data ◽  
Olympic Peninsula ◽  
Last Glacial ◽  
Fossil Insect ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Age-depth model data, images of fossil insect and plant macroscopic remains, lists of skeletal elements for fossil insects, and locality and derived climate data for Olophrum boreale and Olophrum consimile<br>

scholarly journals Initial peopling of North America: paleogeography and archaeology

2019 ◽  
pp. 131-140
Author(s):  
S. A. Vasilyev
Keyword(s):  
North America ◽  
Land Bridge ◽  
Southeastern Part ◽  
Single Wave ◽  
The North ◽  
Human Movements ◽  
The Pacific ◽  
The Usa ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The paper contains a summary of the new data relevant to the time and routes of the first peopling of the New World. The first unambiguous traces of humans are dated by the time span after the Last Glacial Maximum. The chronology and orientation of prehistoric migrations depended on the Late Pleistocene paleogeography. Instead of a postulated single wave of migration oriented from NW to SE from the Bering Land Bridge via the Mackenzie ice-free corridor to the territory lying southwards from the ice sheets we argue about a complicated picture of human movements of different age and direction. It seems that the earliest inhabitants penetrated from Beringia to the main area of North America following the Pacific coast and later dispersed to the east. The migration along the Mackenzie ice-free corridor should have place later. The Clovis culture seems to originate in the southeastern part of the USA territory then dispersing in northern and western directions along the whole continent. The Final Pleistocene saw the ‘inverse’ migration of the Paleoindians to the north, along the Mackenzie corridor to Beringia.

scholarly journals The cave-dwelling dipluran (Diplura, Campodeidae) on the edge of the Last Glacial Maximum in Vancouver Island caves, North America (Canada)

2019 ◽  
Vol 29 ◽  
pp. 59-77 ◽  
Author(s):  
Alberto Sendra ◽  
Craig Wagnell
Keyword(s):  
North America ◽  
Last Glacial Maximum ◽  
Vancouver Island ◽  
Glacial Maximum ◽  
Land Bridge ◽  
Last Glacial ◽  
The North ◽  
Body Distribution ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A new cave-dwelling dipluran of the North American endemic genus Haplocampa is described, coming from a couple of caves excavated in a small limestone karstic area near Port Alberni, Vancouver Island (British Columbia, Canada). To Haplocampa belong five soil-dwelling species. L. M. Ferguson cited no less than eight more species living in soil and cave habitats in several US states but without producing any formal descriptions. Haplocampa, in spite of its large lateral crests on the unequal claws, has clear taxonomical features as a Campodeinae and is closely related with the cave-dwelling Pacificampa and Eumesocampa genera, due to sharing similar macrosetae body distribution and absence or reduction of the lateral process. The new proposed species, Haplocampawagnelli Sendra, sp. n., is rather interesting for its troglomorphic features: antennae with 32 antennomeres; olfactory chemoreceptors, each a multiperforated, folded-spiral structure; and numerous gouge sensilla. In addition, it is one of the northernmost troglomorphic species to have colonised – presumably recently – an area occupied by the Late Wisconsinian North America ice sheet during the Last Glacial Maximum. Furthermore, the close affinities between Haplocampa, Pacificampa (from caves in the extreme east of continental Asia and the southern Japanese Islands), Metriocampa (from the east of Asia and North America) and Eumesocampa (endemic to North America) suggest probable dispersal events over the Bering Land Bridge.

scholarly journals Supplemental Material: Climate of the Last Glacial Maximum on the western Olympic Peninsula based on insect paleoecology

2020 ◽  
Author(s):  
Allan Ashworth ◽  
et al.
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Fossil Insects ◽  
Climate Data ◽  
Model Data ◽  
Olympic Peninsula ◽  
Last Glacial ◽  
Fossil Insect ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Age-depth model data, images of fossil insect and plant macroscopic remains, lists of skeletal elements for fossil insects, and locality and derived climate data for Olophrum boreale and Olophrum consimile<br>

scholarly journals Gridded climate data from 5 GCMs of the Last Glacial Maximum downscaled to 30 arc s for Europe

2015 ◽  
Vol 11 (3) ◽  
pp. 2585-2613 ◽  
Author(s):  
D. R. Schmatz ◽  
J. Luterbacher ◽  
N. E. Zimmermann ◽  
P. B. Pearman
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Baseline Data ◽  
Climate Data ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Very High ◽  
The Last Glacial

Abstract. Studies of the impacts of historical, current and future global change require very high-resolution climate data (≤ 1 km) as a basis for modelled responses, meaning that data from digital climate models generally require substantial rescaling. Another shortcoming of available datasets on past climate is that the effects of sea level rise and fall are not considered. Without such information, the study of glacial refugia or early Holocene plant and animal migration are incomplete if not impossible. Sea level at the last glacial maximum (LGM) was approximately 125 m lower, creating substantial additional terrestrial area for which no current baseline data exist. Here, we introduce the development of a novel, gridded climate dataset for LGM that is both very high resolution (1 km) and extends to the LGM sea and land mask. We developed two methods to extend current terrestrial precipitation and temperature data to areas between the current and LGM coastlines. The absolute interpolation error is less than 1 and 0.5 °C for 98.9 and 87.8 %, respectively, of all pixels within two arc degrees of the current coastline. We use the change factor method with these newly assembled baseline data to downscale five global circulation models of LGM climate to a resolution of 1 km for Europe. As additional variables we calculate 19 "bioclimatic" variables, which are often used in climate change impact studies on biological diversity. The new LGM climate maps are well suited for analysing refugia and migration during Holocene warming following the LGM.

Factors driving the Mediterranean water cycle from a cold and wet glacial past to a warm and dry future

2020 ◽  
Author(s):  
Piero Lionello ◽  
Roberta D'Agostino
Keyword(s):  
Mediterranean Region ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Cmip5 Models ◽  
Climate Conditions ◽  
Atmospheric Thermodynamics ◽  
The Mediterranean ◽  
The Last Glacial Maximum ◽  
Latitudinal Range ◽  
The Last Glacial

&lt;p&gt;Model simulations of the last glacial maximum (LGM) and RCP8.5 projections suggest that factors responsible for past and future changes in the Mediterranean region are different.&amp;#160; The wet LGM conditions were determined mainly by low evaporation, with some increase of precipitation in the western areas, while dry rcp8.5 conditions will be driven by a reduction of precipitation over the whole region. These changes were caused by atmospheric dynamics (changes of mean atmospheric circulation ) in LGM and it will be caused by the atmospheric thermodynamics (reduction of mean moisture content ) in the future rcp8.5. In both cases, the Mediterranean region appears to be more sensitive to climate change than the rest of areas within the same latitudinal range, particularly considering the hydrological cycle, whose characteristics in winter exhibit large changes between these two different climates. These conclusions emerge from the substantial consensus among six PMIP3 and CMIP5 models, simulating LGM, pre-Industrial and rcp8.5 climate conditions.&lt;/p&gt;

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