climate instability during the last interglacial period recorded in the grip ice core isotope and chemical analyses of the grip ice core from summit central greenland reveal that climate in greenland during the last interglacial period was characterized by a series of severe cold periods which began extremely rapidly and lasted from decades to centuries as the last interglacial seems to have been slightly warmer than the present one its unstable climate raises questions about the effects of future global warming

origin and causes of the mammoth steppe a story of cloud cover woolly mammal tooth pits buckles and inside out beringia to account for the vastness of the northern arid steppes during glacial episodes i propose the proximate key variable was simply frequent clear skies this hitherto under emphasized point is the hub which best explains many questions low maritime cloud cover best accounts for today s tundra and in a related way the cloudy polar front accounts for the whole of the taiga even during glacial maxima the proximity of the sea to the bering isthmus created intermittent maritime cloud cover this regional cloud cover produced an ecological interruption or buckle of the arid steppe belt while this beringian mesic buckle did not serve as an intercontinental ecological barrier to most steppe adapted species it does seem to have limited the distributions of woolly rhinos camels american kiangs short faced bears badgers and some others at the beginning of the holocene this narrow refugium seems to have been a source of some mesic adapted species which colonized westward into the now tundra vegetation of northern asia and eastward into northern north america this holocene expansion from a limited and regional pleistocene refugium created our present misconceptions about beringia the mid strait mesic ecological conditions were the exception to the more extensive arid adapted communities of the mammoth steppe 2000 published by elsevier science ltd all rights reserved

diatom evidence on wisconsin and holocene events in the bering sea abstract previous work on surface modern sediments has defined diatom species which appear to be good indicators of various oceanographic ecologic conditions in the north pacific ocean and marginal seas three long cores from the eastern and northern sides of the aleutian basin show changes in species assemblage which can be interpreted in terms of changes in the ocean environment during the last glaciation wisconsin and the holocene the early and late wisconsin maxima were times of prolonged annual sea ice cover and a short cool period of phytoplankton productivity during the ice free season the middle wisconsin interstade at least in the southern bering sea had greater seasonal contrast than today with some winter sea ice cover an intensified temperature minimum and high spring productivity variations in clastic and reworked fossil material imply varying degrees of transport to the basin by alaskan rivers the results of jouse from the central bering sea generally correspond with those presented here although there are problems with direct comparison

late quaternary vegetation of chukotka northeast russia implications for glacial and holocene environments of beringia abstract two lake records from the kankaren region of southern chukotka when combined with other palynological and macrofossil data document spatial and temporal variations in the regional vegetation history since 21 000 14c 25 400 cal yr bp full glacial environments were severely cold and arid in central and northern chukotka whereas southern sites experienced conditions that were relatively moist although still drier than present southern chukotka may represent a western extension of environments of the land bridge proper including a possible moisture barrier to intercontinental migration shrub betula tundra established earliest in southern chukotka 15 800 14 000 14c 19 000 16 700 cal yr bp 13 000 14c 15 300 cal yr bp central and north pinus pumila earliest in the north 9600 14c 11 100 cal yr bp 7600 14c 8400 cal yr bp south and shrub alnus earliest in both the south and north 12 000 11 000 14c 13 800 12 900 cal yr bp these patterns support the presence of cryptic refugia for betula and alnus in chukotka during the full glaciation in contrast p pumila probably migrated into chukotka from populations located in the northern coastal lowlands and from mountainous regions of southwestern beringia evidence for a thermal optimum 11 000 8000 14c 12 900 9000 cal yr bp is strong in northern chukotka but is absent in central and southern areas

late quaternary mis 3 to mis 1 stratigraphic transitions in a highland beringian landscape along the kuskokwim river alaska stratigraphic records extending to marine oxygen isotope stage mis 3 57 000 29 000 cal yr bp or older in beringia are extremely rare three stratigraphic sections in interior western alaska show near continuous sedimentological and environmental progressions extending from at least mis 3 if not older through mis 1 14 000 cal yr bp present the kolmakof sue creek and vabm vertical angle bench mark kuskokwim sections along the central kuskokwim river once a highland landscape at the fringe of central and eastern beringia contain aeolian deposition and soil sequences dating beyond 50 000 14 c yr bp thick peaty soil shallow lacustrine and tephra deposits represent the mis 3 interstade or older sand sheet and loess deposits wedge cast development and very thin soil development mark the later mis 3 period and the transition into the mis 2 stade 29 000 14 000 cal yr bp loess accumulation with thicker soil development occurred between 16 000 13 500 cal yr bp at the mis 2 and mis 1 transition after 13 500 cal yr bp loess accumulation waned and peat development increased throughout mis 1 these stratigraphic sequences represent transitions between a warm and moist period during mis 3 to a cooler and more arid period during mis 2 then a return to warmer and moister climates in mis 1

palaeolithic landscapes of europe and environs 150 000 25 000 years ago an overview abstract when considering the evolution and migrations of neandertalers and early modem human beings the harsh conditions of the last glacial maximum are often implicitly or explicitly assumed as their environmental background this perception is false the conditions of the high glacial apply to a small fraction of late pleistocene time here we review the palaeoenvironmental history of europe from 150 000 to 25 000 years ago with the aid of data from long cores of ice and marine and continental sediments the results are displayed in four sketch maps that illustrate the landscapes of an interglacial glacial cycle the maps connected by palaeoenvironmental histories show that especially between 60 000 and 25 000 years ago a critical part of the palaeolithic the glacial landscapes were for much of the time less barren than is generally assumed but numerous climate changes on a scale of several millennia are evident placing a premium on accurate dating of the co evolution of humans and landscape moreover during the glacial interval abrupt climatic changes lasting from a century to a few millennia were common their importance for landscape changes and their impact on human activity remain to be ascertained

controls on subsurface methane fluxes and shallow gas formation in baltic sea sediment aarhus bay denmark shallow gas accumulates in coastal marine sediments when the burial rate of reactive organic matter beneath the sulfate zone is sufficiently high and the methanogenic zone is sufficiently deep we investigated the controls on methane production and free methane gas accumulation along a 400 m seismo acoustic transect across a sharp transition from gas free into gas bearing sediment in aarhus bay denmark twelve gravity cores were taken in which the pore water was analyzed for inorganic solutes while rates of organic carbon mineralization were measured experimentally by so42 s 35 radiotracer method the thickness of organic rich holocene mud increased from 5 to 10 m along the transect concomitant with a shallowing of the depth of the sulfate methane transition from 4 m to 2 5 m in spite of drastic differences in the distribution of methane and sulfate in the sediment along the transect there were only small differences in total mineralization and methanogenesis was only equivalent to about 1 of sulfate reduction shallow gas appeared where the mud thickness exceeded 8 9 m rates of methanogenesis increased along the transect as did the upward diffusive flux of methane interestingly the increase in the sedimentation rate and holocene mud thickness had only a modest direct effect on methanogenesis rates in deep sediments this increase in methane flux however triggered a shallowing of the sulfate methane transition which resulted in a large increase in methanogenesis at the top of the methanogenic zone thus our results demonstrate a positive feedback mechanism that causes a strong enhancement of methanogenesis and explains the apparently abrupt appearance of gas when a threshold thickness of organic rich mud is exceeded c 2016 elsevier ltd all rights reserved

late cenozoic uplift in southern asia and the american west rationale for general circulation modeling experiments geologic evidence suggests significant increases in uplift rates and absolute elevation in several areas during the late cenozoic especially in the last 10 m y regions of major uplift include the tibetan plateau and himalayan mountains of southern asia and the sierra nevada colorado plateau basin and range rocky mountains and high plains of the american west uplift occurred at a scale large enough to affect regional and global climate in a number of ways several of which we evaluate by general circulation model experiments in accompanying papers

a pleistocene sand sea on the alaskan arctic coastal plain a ridge and thermokarst basin landscape that is strikingly portrayed in landsat winter imagery consists of large pleistocene dunes that have been modified by younger eolian activity and thermokarst processes this is the most extensive area of large stabilized dunes yet reported in the north american arctic the landscape is of particular interest because it has been proposed as a first order analog for martian fretted terrain recognition of the large dunes permits a new interpretation for linear and curvilinear trends visible in landsat summer imagery

forcing of late cenozoic northern hemisphere climate by plateau uplift in southern asia and the american west geologic evidence indicates that net vertical uplift occurred on a large kilometer scale and at accelerating rates during the middle and late cenozoic in plateaus of southern asia and the american west based on this evidence general circulation model sensitivity tests were run to isolate the unique effects of plateau uplift on climate the experiments simulated significant climatic changes in many places some far from the uplifted regions the basic direction of most of these simulated responses to progressive uplift is borne out by changes found in the geologic record winter cooling of north america northern europe northern asia and the arctic ocean summer drying of the north american west coast the eurasian interior and the mediterranean winter drying of the north american northern plains and the interior of asia and changes over the north atlantic ocean conducive to increased formation of deep water the modeled changes result from increased orographic diversion of westerly winds from cyclonic and anticyclonic surface flow induced by summer heating and winter cooling of the uplifted plateaus and from the intensification of vertical circulation cells in the atmosphere caused by exchanges of mass between the summer heated and winter cooled plateaus and the mid latitude oceans disagreements between the geologic record and the model simulations in alaska and the southern rockies and plains may be related mainly to the lack of narrow mountain barriers in the model orography taken together the observed regional trends comprise much of the pattern of late cenozoic climatic deterioration in the northern hemisphere that culminated in the plio pleistocene ice ages the success of the uplift sensitivity experiment in simulating the correct pattern and sign of most of the observed regional climatic trends points to uplift as an important forcing function of late cenozoic climatic change in the northern hemisphere at time scales longer than orbital variations however the modest amplitude of the uplift induced cooling simulated at high latitudes indicates a probable need for additional climatic forcing

modeling the effects of land sea roughness contrast on tropical cyclone winds abstract the fifth generation pennsylvania state university national center for atmospheric research psu ncar mesoscale model mm5 is used to simulate tropical cyclone tc wind distribution near landfall on an f plane at 15 n the effects of the different surface roughness between the land and sea on the wind asymmetry is examined under a strong constraint of a dry atmosphere and time invariant axisymmetric mass fields the winds are found to adjust toward a steady state for prelandfall 50 100 and 150 km offshore landfall and postlandfall 50 100 and 150 km inland tc positions the tc core is asymmetric even when it lies completely offshore or inland the surface 10 m wind asymmetry at the core for pre post landfall position is apparently related to the acceleration deceleration of the flow that has just moved over the sea land as a response to the sudden change of surface friction for prelandfall tc positions the resulted strong surface inflow to the left and front left relative

results of the cerpolex mammuthus expeditions on the taimyr peninsula arctic siberia russian federation during a series of expeditions organized by cerpolex mammuthus to the taimyr region in northern siberia several mammoth mammuthus primigenius carcasses were discovered and subsequently excavated and studied the oldest specimen is the arilakh mammoth ca 55 800 bp much younger are the jarkov mammoth ca 20 380 bp and the fishhook mammoth ca 20 620 bp and still much younger are well preserved holocene mammoth remains 10 000 bp some paleobotanical data and descriptions of accompanying fauna provide insight into the ecology of the region during late pleistocene times the faunal collapse at the end of the pleistocene seems to be the result of increasing temperatures greater humidity increased snow cover formation of insulating plant layers later thawing of the soil and a lower herbivore density amplifying the climatic effects c 2005 elsevier ltd and inqua all rights reserved

a framework for interpreting paleoclimatic variations in eastern beringia abstract paleoclimatic variations in a particular region can be viewed as the outcome of the superimposition of the effects of a number of large scale controls a framework for understanding paleoclimatic variations in a region can be established by considering the long term history of those controls jointly with climatic modeling results that illustrate how regional climates respond to changes of individual controls the relevant controls of late quaternary paleoclimatic variations in eastern beringia include 1 the size of the ice sheet which influences both atmospheric circulation and temperature 2 insolation which influences mainly temperature and seasonality 3 carbon dioxide concentration in the atmosphere which influences temperature and 4 feedbacks involving sea ice sea surface temperatures and snow cover which reinforce the insolation effects we review the results of a number of paleoclimatic experiments with general circulation models to illustrate the potential response of eastern beringia to the variations of these controls we then present a framework for understanding paleoclimatic variations in eastern beringia by describing the likely responses of the climate of this region to the known variations in the controls in addition we discuss key times during the quaternary when particular combinations of the controls give rise to natural experiments which lend themselves to the testing of particular hypotheses our understanding of the nature of climatic variations at high latitudes should increase through examination of paleoclimatic evidence that documents the response of the region at those key times

late pleistocene eolian sand sheets in alaska abstract nonglaciated lowlands in central and southwestern alaska contain extensive deposits of upper quaternary eolian sand derived largely from major outwash rivers although surface dunes are common deep exposures consistently reveal that subhorizontally stratified sand and silt deposits dominate over dune cross strata we hypothesize that 1 many of the subhorizontally stratified deposits represent full glacial eolian sand sheets formed when sand supply was limited by seasonally variable combinations of ice cementation snow cover high groundwater tables and vegetation and 2 many surface dunes reflect late glacial and postglacial reworking under conditions of increased short term availability of loose sand the morphology of some surface dunes may therefore reflect mainly the intensity of reworking since the last glacial maximum rather than full glacial paleowind vectors or the age of the bulk of the underlying deposits

aeolian stratigraphy describes ice age paleoenvironments in unglaciated arctic alaska abstract terrestrial paleoenvironmental records with high dating resolution extending into the last ice age are rare from the western arctic such records can test the synchronicity and extent of ice age climatic events and define how arctic landscapes respond to rapid climate changes here we describe the stratigraphy and sedimentology of a yedoma deposit in arctic alaska the carter section dating to between 37 000 and 9000 calibrated radiocarbon years bp 37 9 ka and containing detailed records of loess and sand sheet sedimentation soil development carbon storage and permafrost dynamics alternation between sand sheet and loess deposition provides a proxy for the extent and activity of the ikpikpuk sand sea iss a large dune field located immediately upwind warm moist interstadial times ca 37 36 3 32 5 and 15 13 ka triggered floodplain aggradation permafrost thaw reduced loess deposition increased vegetation cover and rapid soil development accompanied by enhanced carbon storage during the last glacial maximum lgm ca 28 18 ka rapid loess deposition took place on a landscape where vegetation was sparse and non woody the most intense aeolian activity occurred after the lgm between ca 18 and 15 ka when sand sheets fringing the iss expanded over the site possibly in response to increasingly droughty conditions as summers warmed and active layers deepened with the exception of this lagged lgm response the record of aeolian activity at the carter section correlates with other paleoenvironmental records from unglaciated siberia and alaska overall rapid shifts in geomorphology soils vegetation and permafrost portray an ice age landscape where in contrast to the holocene environmental change was chronic and dominated by aeolian processes

paleolithic socionatural relationships during mis 3 and 2 in central portugal abstract throughout the pleistocene climatic shifts repeatedly impacted the mediterranean region in response to these perturbations the mediterranean bioclimatic zones evolved as some of the most diverse dynamic and resilient in the world the appearance of modern humans in western iberia 30 35 ka co occurred with important environmental changes especially regarding animal communities these transformations are associated with the onset of mis 2 and introduction of new land use practices combined data from zooarchaeological paleontological and paleovegetation records are used to identify patterns in human environment interaction at different spatial and temporal scales evidence suggests that humans modified their environment creating long term dynamic and resilient socionatural systems during the upper paleolithic

high resolution multi proxy climate records from chinese loess evidence for rapid climatic changes over the last 75 kyr the loess paleosol sequence in loess layer l1 malan loess is investigated in three regions of the western chinese loess plateau nine pedogenic layers are found in l1 and three proxy climate indices magnetic susceptibility ms grain size gs and caco3 content are measured at intervals of 0 2 kyr in order to recover records of monsoon climate variations time series of ms gs and caco3 content document the high resolution history of summer and winter monsoon climate variations over the last 75 kyr the records show a high degree of similarity to the warm interstadials recorded in ice cores from greenland and the antarctic and with heinrich events in the north atlantic during the last glacial cycle bond cycles are also recorded by the chinese loess records overall our results indicate that numerous rapid changes in climate occurred in china during the last glacial cycle but that the range of climate variations was smaller than recorded in greenland

climate change and arctic ecosystems 1 vegetation changes north of 55 n between the last glacial maximum mid holocene and present a unified scheme to assign pollen samples to vegetation types was used to reconstruct vegetation patterns north of 55 n at the last glacial maximum lgm and mid holocene 6000 years b p the pollen data set assembled for this purpose represents a comprehensive compilation based on the work of many projects and research groups five tundra types cushion forb tundra graminoid and forb tundra prostrate dwarf shrub tundra erect dwarf shrub tundra and low and high shrub tundra were distinguished and mapped on the basis of modern pollen surface samples the tundra forest boundary and the distributions of boreal and temperate forest types today were realistically reconstructed during the mid holocene the tundra forest boundary was north of its present position in some regions but the pattern of this shift was strongly asymmetrical around the pole with the largest northward shift in central siberia 200 km little change in beringia and a southward shift in keewatin and labrador 200 km low and high shrub tundra extended farther north than today at the lgm forests were absent from high latitudes graminoid and forb tundra abutted on temperate steppe in northwestern eurasia while prostrate dwarf shrub erect dwarf shrub and graminoid and forb tundra formed a mosaic in beringia graminoid and forb tundra is restricted today and does not form a large continuous biome but the pollen data show that it was far more extensive at the lgm while low and high shrub tundra were greatly reduced illustrating the potential for climate change to dramatically alter the relative areas occupied by different vegetation types

radiocarbon age offsets in an arctic lake reveal the long term response of permafrost carbon to climate change continued warming of the arctic may cause permafrost to thaw and speed the decomposition of large stores of soil organic carbon oc thereby accentuating global warming however it is unclear if recent warming has raised the current rates of permafrost oc release to anomalous levels or to what extent soil carbon release is sensitive to climate forcing here we use a time series of radiocarbon age offsets 14c between the bulk lake sediment and plant macrofossils deposited in an arctic lake as an archive for soil and permafrost oc release over the last 14 500 years the lake traps and archives oc imported from the watershed and allows us to test whether prior warming events stimulated old carbon release and heightened age offsets today the age offset 2 ka thousand of calibrated years before a d 1950 and the depositional rate of ancient oc from the watershed into the lake are relatively low and similar to those during the younger dryas cold interval occurring 12 9 11 7 ka in contrast age offsets were higher 3 0 5 0 ka when summer air temperatures were warmer than present during the holocene thermal maximum 11 7 9 0 ka and bolling allerod periods 14 5 12 9 ka during these warm times permafrost thaw contributed to ancient oc depositional rates that were 10 times greater than today although permafrost oc was vulnerable to climate warming in the past we suggest surface soil organic horizons and peat are presently limiting summer thaw and carbon release as a result the temperature threshold to trigger widespread permafrost oc release is higher than during previous warming events

pleistocene periglacial eolian deposits in southwestern alaska sedimentary facies and depositional processes abstract pleistocene periglacial eolian sediments are widespread in the nushagak holitna and upper kuskokwim lowlands of southwestern alaska these sediments comprise mainly sand sheet deposits and sand loess intergrades with subordinate sand dune deposits and loess sand sheet deposits range from 1 sharply defined parallel low angle laminae formed by migrating wind ripples to 2 irregular subhorizontal strata which reflect migration of poorly segregated wind ripples accumulation on a sparsely vegetated surface adhesion on a quasi planar bed and or niveo eolian deposition sand loess intergrades represent alternating bed load and suspension deposition related mainly to the stochastic and seasonal variability of former wind systems the dominance of sand sheet deposits over deposits of well formed dunes in the pleistocene eolian record of southwestern alaska reflects the limited availability of loose dry sand in this former periglacial environment immobilization of sand after deposition as low relief sheets resulted from a seasonally variable combination of ice cementation sparse vegetation high water tables and snow cover

new perspectives on beringian quaternary paleogeography stratigraphy and glacial history abstract aspects of the paleogeography stratigraphy and glacial history of beringia have been greatly revised over the past 15 20 yr access to north east russia in particular has provided the opportunity to evaluate the beringia landscape as a contiguous subcontinent during the quaternary for the first time new research has made clearer the connection between tectonic forces and the submergence of the bering strait during the middle pliocene revisions in the regional stratigraphy of glacial and interglacial deposits in northwest alaska and northeast russia provide a new foundation for assessing the causes for differences in glacial ice extent through time the consensus of all field workers verifies that glacial ice throughout most of beringia was of very limited extent during the last glacial maximum the onset of regional glaciation during the waning stages of the last interglaciation is clearly out of phase with glaciation at lower latitudes despite the lack of much glacial activity during the early holocene alaska contains a rich record of late holocene glacial response to neoglacial cooling changes in the holocene environment of beringia likely had a profound affect on early inhabitants the curiosity driven vision and spirit of both david hopkins and the late troy pewe have had a profound influence on arctic paleoenvironmental research

late pleistocene vertebrates and other fossils from epiguruk northwestern alaska abstract sediments exposed at epiguruk a large cutbank on the kobuk river about 170 km inland from kotzebue sound record multiple episodes of glacial age alluviation followed by interstadial downcutting and formation of paleosols vertebrate remains from epiguruk include mammoth bison caribou an equid a canid arctic ground squirrel lemmings and voles radiocarbon ages of bone validated by concordant ages of peat and wood span the interval between about 37 000 and 14 000 yr b p the late pleistocene pollen record is dominated by cyperaceae with artemisia salix betula and gramineae also generally abundant the fossil record from epiguruk indicates that the kobuk river valley supported tundra vegetation with abundant riparian willows during middle and late wisconsin time large herbivores were present during the height of late wisconsin glaciation as well as during its waning stage and the preceding interstadial interval the kobuk river valley would have been a favorable refugium for plants animals and possibly humans throughout the last glaciation

a coupled environmental system formed at about 2 5 ma in east asia abstract the somewhat abrupt commencement of loess deposition on a large scale in north central china is palaeomagnetically measured at about 2 5 ma the formation of the dynamical conditions responsible for windblown loess processes implies a reorganization of the atmospheric circulation over eastern asia it is speculated that at that time the accelerated uplift of the tibetan plateau had reached a threshold height giving rise to the intensification and northward shift of the siberian high and deepening of the cyclone in the lee of the tibetan plateau the uplift of tibet and the resulting reorganization of atmospheric circulation at about 2 5 ma would initiate a coupled environmental system tibetan plateau inland desert loess plateau in eastern asia that could be a key system in understanding the onset of glaciation in northern hemisphere and climatic change in the quaternary the climatic shift from near continuous warm condition before 2 5 ma to frequent and chaotic fluctuations after is speculated to be triggered to a significant extent by the uplift of the tibetan plateau an orography cold surge albedo temperature feedback mechanism is developed in explaining the harsher climate over east asia during glacial time and is thought to be one of the major contributors in promoting glacial development on the globe

late quaternary lacustrine pollen records from southwestern beringia sediment cores from three lakes in the upper kolyma region northeast russia provide the first well dated continuous record of late quaternary vegetation change from far southwestern beringia the oldest pollen zone tentatively assigned to the karginsk mid wisconsinan interstade indicates an artemisia shrub tundra with pinus pumila betula and alnus at mid to low elevations with the onset of the sartan late wisconsinan stade pinus disappeared probably indicating severely cold dry winters and cool summers as conditions deteriorated further an artemisia gramineae tundra developed selaginella rupestris and minor herb taxa indicate the presence of poor soils and disturbed ground this herb tundra was replaced by a short lived 1000 yr betula alnus shrub tundra followed by the rapid establishment of a larix dahurica forest with a betula exilis ericales lichen understory populus suaveolens and chosenia may have formed limited hardwood gallery forests at this time modern vegetation associations probably developed during the early holocene with the arrival of pinus pumila ca 9000 yr b p this shrub became important in the forest understory and with b exilis formed a belt of shrub tundra beyond altitudinal treeline comparison of the upper kolyma and alaskan pollen records indicates that important differences in vegetation types and timing of vegetation change occurred across beringia during the late quaternary

late quaternary paleoclimate of western alaska inferred from fossil chironomids and its relation to vegetation histories abstract fossil chironomidae assemblages with a few chaoboridae and ceratopogonidae from zagoskin and burial lakes in western alaska provide quantitative reconstructions of mean july air temperatures for periods of the late middle wisconsin 39 000 34 000 cal yr b p to the present inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordination paleotemperature trends reveal substantial differences in the timing of climatic warming following the late wisconsin at each site although chronological uncertainty exists zagoskin lake shows early warming beginning at about 21 000 cal yr b p whereas warming at burial lake begins 4000 years later summer climates during the last glacial maximum lgm were on average 3 5 c below the modern temperatures at each site major shifts in vegetation occurred from 19 000 to 10 000 cal yr b p at zagoskin lake and from 17 000 to 10 000 cal yr b p at burial lake vegetation shifts followed climatic warming when temperatures neared modern values both sites provide evidence of an early postglacial thermal maximum at 12 300 cal yr b p these chironomid records combined with other insect based climatic reconstructions from beringia indicate that during the lgm 1 greater continentality likely influenced regions adjacent to the bering land bridge and 2 summer climates were at times not dominated by severe cold

correlation between climate events in the north atlantic and china during the last glaciation episodes of massive iceberg release heinrich events 1 3 into the north atlantic ocean during the last glaciation were associated with recurring episodes of unusually cold north atlantic surface water bond cycles 4 and cold air temperatures over greenland dansgaard oeschger events 5 6 four of the youngest of these cold events have also been reported in climate records from sites outside the north atlantic region7 but until now the entire suite has been identified only in north atlantic marine sediments greenland ice core records and tentatively in french lake sediments8 here we examine grain size data from chinese loess and intercalated accretionary palaeosols of last glacial age for evidence of similar climate signals remote from the north atlantic region we see grain size maxima with ages that match those of the last six heinrich events which we interpret as an indication of the changing strength of the east asian winter monsoon which largely controls the transport and deposition of central asian aeolian dust thus it seems that these heinrich events have left their signature in the chinese loess record this is consistent with simulations of the glacial climate9 which imply that the climates of the north atlantic and china were linked by the effect of westerly winds