Orbital- and millennial-scale vegetation and climate changes of the past 225 ka from Bear Lake,Utah–Idaho (USA)

Continuous high-resolution pollen data for the past 225 ka from sediments in Bear Lake, Utah–Idaho reflect changes in vegetation and climate that correlate well with variations in summer insolation and global ice-volume during MIS 1 through 7. Spectral analysis of the pollen data identified peaks at 21–22 and 100 ka corresponding to periodicities in Earth's precession and eccentricity orbital cycles. Suborbital climatic fluctuations recorded in the pollen data, denoted by 6 and 5 ka cyclicities, are similar to Greenland atmospheric temperatures and North Atlantic ice-rafting Heinrich events. Our results show that millennial-scale climate variability is also evident during MIS 5, 6 and 7, including the occurrence of Heinrich-like events in MIS 6, showing the long-term feature of such climate variability. This study provides clear evidence of a highly interconnected ocean–atmosphere system during the last two glacial/interglacial cycles that extended its influence as far as continental western North America. Our study also contributes to a greater understanding of the impact of long-term climate change on vegetation of western North America. Such high-resolution studies are particularly important in efforts of the scientific community to predict the consequences of future climate change.     

Coupled atmospheric and marine palaeoclimatic reconstruction for the last 35 ka in the Sele Plain–Gulf of Salerno area (southern Italy)

Planktonic foraminifera and pollen data from core GNS84-C106 (Gulf of Salerno, Tyrrhenian Sea) were analysed through the Modern Analogue Technique, Constrained Cluster Analysis and relative variation biplots. A long period of mild climate, centred around 25 ka BP, is evident in both marine and continental reconstructions. The cooling phase from 17 to 14.7 ka BP, correlated to the H1 Heinrich event, is indicated by a sea surface temperature (SST) decrease, which roughly coincides with the cold-arid phase identified by annual and January temperatures. A rapid increase in atmospheric temperatures and precipitation, culminating at 13.8 ka BP, marks the BA cronozone. The corresponding increase in summer and winter SSTs, of 11 and 6.5 °C, respectively, occurred over 600 years. The beginning of the YD, centred around 12.5 ka BP, is marked by a decrease in summer and winter SSTs of, respectively, 4.5 and 3.5 °C in one century. The atmospheric evidence of the YD is primarily reflected in low January temperatures, reaching −6 °C, the lowest values ever experienced in the analysed time interval. The Late Glacial–Holocene transition is clearly recorded in both the continental and marine realms. From 11.5 to 9 ka BP, atmospheric temperatures record a period of substantial stability followed by a drop at 8.9 ka BP, which chronologically fall within the first RCC event (9–8 ka BP) of Mayewski et al. [2004. Holocene climate variability. Quaternary Research 62, 243–255], in correspondence with a phase of relatively high seasonality, indicated by foraminifera.     

50,000 years of vegetation and climate history on the Colorado Plateau, Utah and Arizona, USA

Sixty packrat middens were collected in Canyonlands and Grand Canyon National Parks, and these series include sites north of areas that produced previous detailed series from the Colorado Plateau. The exceptionally long time series obtained from each of three sites (> 48,000 ¹⁴C yr BP to present) include some of the oldest middens yet discovered. Most middens contain a typical late-Wisconsinan glaciation mixture of mesic and xeric taxa, evidence that plant species responded to climate change by range adjustments of elevational distribution based on individual criteria. Differences in elevational range from today for trees and shrubs ranged from no apparent change to as much as 1200 m difference. The oldest middens from Canyonlands NP, however, differ in containing strictly xeric assemblages, including middens incorporating needles of Arizona single-leaf pinyon, far north of its current distribution. Similar-aged middens from the eastern end of Grand Canyon NP contain plants more typical of glacial climates, but also contain fossils of one-seed juniper near its current northern limit in Arizona. Holocene middens reveal the development of modern vegetation assemblages on the Colorado Plateau, recording departures of mesic taxa from low elevation sites, and the arrival of modern dominant components much later.     

Glacial and climate history of the last 24 000 years in the Polar Ural Mountains,Arctic Russia,inferred from partly varved lake sediments

We present a well‐dated, high‐resolution and continuous sediment record spanning the last c. 24 000 years from lake Bolshoye Shchuchye located in the Polar Ural Mountains, Arctic Russia. This is the first continuous sediment succession reaching back into the Last Glacial Maximum (LGM) ever retrieved from this region. We reconstruct the glacial and climate history in the area since the LGM based on sedimentological and geochemical analysis of a 24‐m‐long sediment core. A robust chronology was established using a combination of AMS ¹⁴C‐dating, the position of the Vedde Ash and varve counting. The varved part of the sediment core spans across the LGM from 24 to 18.7 cal. ka BP. We conclude that the lake basin remained ice‐free throughout the LGM, but that mountain glaciers were present in the lake catchment. A decrease in both glacial varve preservation and sedimentation rate suggests that these glaciers started to retreat c. 18.7 cal. ka BP and had disappeared from the catchment by 14.35 cal. ka BP. There are no indications of glacier regrowth during the Younger Dryas. We infer a distinct climatic amelioration following the onset of the Holocene and an Early to Middle Holocene thermal optimum between 10–5 cal. ka BP. Our results provide a long‐awaited continuous and high‐resolution record of past climate that supplements the existing, more fragmentary data from moraines and exposed strata along river banks and coastal cliffs around the Russian Arctic.     

Frequency and intensity of high-altitude floods over the last 3.5 ka in northwestern French Alps (Lake Anterne)

In central Western Europe, several studies have shown that colder Holocene periods, such as the Little Ice Age, also correspond to wet periods. However, in mountain areas which are highly sensitive to erosion processes and where precipitation events can be localized, past evolution of hydrological activity might be more complicated. To assess these past hydrological changes, a paleolimnological approach was applied on a 13.4-m-long sediment core taken in alpine Lake Anterne (2063 m asl) and representing the last 3.5 ka. Lake sedimentation is mainly composed of flood deposits triggered by precipitation events. Sedimentological and geochemical analyses show that floods were more frequent during cold periods while high-intensity flood events occurred preferentially during warmer periods. In mild temperature conditions, both flood patterns are present. This underlines the complex relationship between flood hazards and climatic change in mountain areas. During the warmer and/or dryer times of the end of Iron Age and the Roman Period, both the frequency and intensity of floods increased. This is interpreted as an effect of human-induced clearing for grazing activities and reveals that anthropogenic interferences must be taken into account when reconstructing climatic signals from natural archives.     

The response of NW Iberian vegetation to North Atlantic climate oscillations during the last 65 kyr

Pollen and oceanographic data from deep ocean core MD95-2039 provide a centennial to millennial scale record of conditions offshore and of the vegetation of north-west Iberia for the period 10–65 ka. The planktonic oxygen isotope record of this core, reflecting predominantly sea surface temperature (SST), shows a pattern of millennial-scale oscillations that is very similar to climatic changes recorded by the Greenland ice core records over the same interval. In turn, tree populations show a pattern of rapid expansions and contractions that follow the pronounced and abrupt isotopic shifts recorded offshore. Through Marine Isotope Stage (MIS) 3, this millennial-scale pattern of vegetation change, alternating between steppe and open woodland, is superimposed on a longer-term pattern of shrinking ericaceous heathland and decreasing size of successive interstadial tree populations. Trees persisted during the Last Glacial Maximum (LGM), at greater abundance than during many of the coldest episodes of MIS 3. This agrees with the marine data which indicate that LGM sea surface temperatures here were significantly warmer than the minima recorded in MIS 3. Our combined marine-terrestrial record, together with data from nearby sequences, provides a stepping stone between terrestrial sequences and the Greenland ice core and North Atlantic marine records. This will permit a better understanding of the behaviour of vegetation across different regions at several scales of climatic forcing.     

Environmental reconstructions of the upper 500 m of the southern Indian Ocean over the last 40 ka using Radiolarian (Protista) proxies

In 2007, we demonstrated that radiolarians are proxies for a wide range of oceanic physico-chemical properties from the surface to depths of up to 500 m below sea level. In this study, our results are refined and Correspondence Analysis (CA) scores derived from census counts of radiolarian subfossils from southern Indian Ocean core-tops are correlated with the physico-chemical properties of the region obtained from the 2005 World Ocean Database.Calibration and regression techniques are employed to reconstruct palaeoenvironmental conditions spanning the last 40 ka for four Indian Ocean cores MD88-769 [46°04′S 90°06′E], MD88-770 [46°01′S 96°27′E], MD94-102 [43°30′S 79°50′E], and MD94-103 [45°35′S 86°31′E], all from close to the Southeast Indian Ridge. For the first time, reconstructions of temperature, salinity, dissolved oxygen, and the silicate, nitrate, and phosphate concentrations for a range of water depths are proved possible.Changes of the oceanic environment and the movement of water masses over the last 40 ka, as suggested by these reconstructions, are discussed. During Marine Isotope Stages 2 and 3 (MIS-2 and MIS-3), the water column at some of the core sites has similar characteristics to the waters south of the Polar Front today. At the MIS-1/MIS-2 transition, the development of the Subantarctic Mode Water is apparent. Temperature reconstructions include evidence of the Antarctic Cold Reversal and the Holocene Optimum.     

The luminescence dating chronology of a deep core from Bosten Lake (NW China) in arid central Asia reveals lake evolution over the last 220 ka

The lacustrine deposits of lakes in arid central Asia (ACA) potentially record palaeoclimatic changes on orbital and suborbital time scales, but such changes are still poorly understood due to the lack of reliable chronologies. Bosten Lake, the largest freshwater inland lake in China, is located in the southern Tianshan Mountains in central ACA. A 51.6‐m‐deep lacustrine succession was retrieved from the lake and 30 samples from the succession were used for luminescence dating to establish a chronology based on multi‐grain quartz OSL and K‐feldspar post‐IR IRSL (pIRIR₂₉₀) dating. Quartz OSL ages were only used for samples from the upper part of the core. The K‐feldspar luminescence characteristics (dose recovery test, anomalous fading test, first IR stimulation temperature plateau test) are satisfactory and from the relationship amongst the quartz OSL, IR₅₀ and pIRIR₂₉₀ doses we infer that the feldspar signals are likely to be well bleached at deposition. Bacon age‐depth modelling was used to derive a chronology spanning the last c. 220 ka. The chronology, lithology and grain‐size proxy record indicate that Bosten Lake formed at least c. 220 ka ago and that lake levels fluctuated frequently thereafter. A stable deep lake occurred at c. 220, 210–180, c. 165, 70–60, 40–30 and 20–5 ka, while shallow levels occurred at c. 215, 180–165, 100–70, 60–40 and 30–20 ka. Bosten Lake levels decreased by at least ~29 m and possibly the lake even dried up between c. 160 and c. 100 ka. We suggest that the water‐level fluctuations in the lakes of ACA may not respond directly to climatic changes and may be affected by a number of complex factors.     

Pollen records of vegetation and inferred climate change in southwestern Madhya Pradesh during the last ca. 3800 years

Pollen analysis of 1.5m deep sediment core from Sapna Lake, Betul District (M.P.) has demonstrated that between 3,800 and 2,700 yr BP, open Acacia-dominant scrub forests interspersed with stretches of herbaceous vegetation comprising grasses, sedges, Asteraceae, Cheno/Am, etc., occurred in the region under a regime of dry climate. A few trees of Madhuca indica, Holoptelea, Shorea robusta, Lagerstroemia parviflora, etc. were also sparingly distributed therein. The vicinity of the lake was under cereal-based agricultural practice as portrayed by the presence of Cerealia and other culture pollen taxa viz., Cheno/Am, Caryophyllaceae, Artemisia and Cannabis sativa. Around 2,700 to 1,260 yr BP the Acacia-dominant scrub forests were succeeded by the open mixed deciduous forests as evidenced from the improvement in frequencies of Madhuca indica, Sapotaceae, Holoptelea, Shorea robusta as well as sporadic invasion of Terminalia, Mitragyna, Flacourtia, Grewia, Lannea coromandelica, etc. This enhancement in the forest floristic reflects the initiation of a warm and humid climate possibly in response to increasing monsoon precipitation. Owing to the prevailing favourable climatic condition there was acceleration in the agricultural practice as indicated by the rising trend of Cerealia and other culture pollen taxa. Since 1,260 yr BP onwards the depletion in the prominent forest constituents such as Madhuca indica, Sapotaceae, Shorea robusta, Holoptelea and other associated trees implies that the forests turned more sparse and less diversified due to the inception of a warm and less humid climate, attributable to reduced monsoon precipitation. However, the agricultural practice continued with almost same intensity as before, because the Cerealia and other culture pollen taxa remain unchanged.     

Climatic and environmental changes in the Yana Highlands of north-eastern Siberia over the last c. 57 000 years,derived from a sediment core from Lake Emanda

The sediment succession of Lake Emanda in the Yana Highlands was investigated to reconstruct the regional late Quaternary climate and environmental history. Hydro-acoustic data obtained during a field campaign in 2017 show laminated sediments in the north-western and deepest (up to ̃15 m) part of the lake, where a ̃6-m-long sediment core (Co1412) was retrieved. The sediment core was studied with a multi-proxy approach including sedimentological and geochemical analyses. The chronology of Co1412 is based on ¹⁴C AMS dating on plant fragments from the upper 4.65 m and by extrapolation suggests a basal age of c. 57 cal. ka BP. Pronounced changes in the proxy data indicate that early Marine Isotope Stage (MIS) 3 was characterized by unstable environmental conditions associated with short-term temperature and/or precipitation variations. This interval was followed by progressively colder and likely drier conditions during mid-MIS 3. A lake-level decline between 32.0 and 19.1 cal. ka BP was presumably related to increased continentality and dry conditions peaking during the Last Glacial Maximum (LGM). A subsequent rise in lake level could accordingly have been the result of increased rainfall, probably in combination with seasonally high meltwater input. A milder or wetter Lateglacial climate increased lake productivity and vegetation growth, the latter stabilizing the catchment and reducing clastic input into the lake. The Bølling-Allerød warming, Younger Dryas cooling and Holocene Thermal Maximum (HTM) are indicated by distinct changes in the environment around Lake Emanda. Unstable, but similar-to-present-day climatic and environmental conditions have persisted since c. 5 cal. ka BP. The results emphasize the highly continental setting of the study site and therefore suggest that the climate at Lake Emanda was predominantly controlled by changes in summer insolation, global sea level, and the extent of ice sheets over Eurasia, which influenced atmospheric circulation patterns.     

Complexity of the 8 ka climate event in Sweden recorded by varved lake sediments

Mineral magnetic and carbon analyses of a continuous varved lake sediment sequence in west-central Sweden (Lake Mötterudstjärnet) complement similar palaeoclimate proxies obtained from two varved lake sediment sequences in northern Sweden and one in central Finland. The varve chronology is supported by tephrochronology, palaeomagnetic secular variations and ¹⁴C AMS dating of terrestrial macrofossils. We apply a simple model in which the transport and deposition of catchment mineral matter reflect the amount of winter snow accumulation, spring snow-melt and stream discharge. Our data show that winter snow accumulation was generally enhanced in Sweden between 8100 and 7750 cal. yr BP. If dating errors are taken into account, the 350-year period of increased erosion is the geomorphic response to a multi-centennial scale climatic cooling that occurred some time between 8500 and 7500 cal. yr BP. The most significant erosion event in central Sweden was centred at 8050 cal. yr BP. It lasted 150 years (between 8100 and 7950 cal. yr BP) and is equivalent to the most extreme Holocene climate anomaly in the northern hemisphere, known as the 8 ka or 8200 cal. yr BP climate event. Our high-resolution paramagnetic susceptibility and ferrimagnetic grain-size parameters suggest that snowpack accumulation increased most significantly in northern Sweden between 7900 and 7750 cal. yr BP. We suggest that this north–south difference was a response to the re-establishment of moisture-laden westerly air masses, as meridional Atlantic overturning circulation was re-established at the beginning of the Holocene thermal maximum.     

Sediment instability on the Portuguese continental margin under abrupt glacial climate changes (last 60 kyr)

It is well established that orbital scale sea-level changes generated larger transport of sediments into the deep-sea during the last glacial maximum than the Holocene. However, the response of sedimentary processes to abrupt millennial-scale climate variability is rather unknown. Frequency of distal turbidites and amounts of advected detrital carbonate are estimated off the Lisbon–Setúbal canyons (core MD03-2698, at 4602 mwd), within a chronostratigraphy based on radiometric ages, oxygen isotopes and paleomagnetic key global anomalies. We found that: 1) higher frequency of turbidites concurred with Northern Hemisphere coldest temperatures (Greenland Stadials [GS], including Heinrich [H] events). But more than that, an escalating frequency of turbidites starts with the onset of global sea-level rising (and warming in Antarctica) and culminates during H events, at the time when rising is still in its early-mid stage, and the Atlantic Meridional Overturning Circulation (AMOC) is re-starting. This short time span coincides with maximum gradients of ocean surface and bottom temperatures between GS and Antarctic warmings (Antarctic Isotope Maximum; AIM 17, 14, 12, 8, 4, 2) and rapid sea-level rises. 2) Trigger of turbidity currents is not the only sedimentary process responding to millennial variability; land-detrital carbonate (with a very negative bulk δ¹⁸O signature) enters the deep-sea by density-driven slope lateral advection, accordingly during GS. 3) Possible mechanisms to create slope instability on the Portuguese continental margin are sea-level variations as small as 20 m, and slope friction by rapid deep and intermediate re-accommodation of water masses circulation. 4) Common forcing mechanisms appear to drive slope instability at both millennial and orbital scales.     

A lacustrine record of early Holocene watershed events and vegetation history,Corvara in Badia,Dolomites (Italy)

The early–middle Holocene lacustrine succession of Corvara in Badia (Italian Dolomites, 1521 m a.s.l.) records landslides and other watershed events before the onset of human pressure. The sensitivity of this archive to relate climate change, watershed processes and vegetation dynamics in the catchment has been explored through a stratigraphic study, including the analysis of sedimentological features, magnetic properties, palaeobotanical records and radiocarbon dating. A palaeolake existed between 10.1 k and 7 k cal. yr BP and was surrounded by a dense conifer forest. Long‐term forest dynamics driven by ecological processes and by climatic conditions favourable to upward forest expansion is recorded throughout the pollen record. Within the fine clastic sedimentation, distinct layers enriched in organic debris of terrestrial origin have been attributed to instant events produced by mass movements. Their age fits the chronology of large landslide events already known in the catchment, enabling correlation of the field evidence of landslides with the lacustrine record. Landslide frequency is controlled by geological and structural factors, but it is significantly modulated by the centennial–millennial climatic phases that characterise the Holocene in the Alps. The taphonomical properties of pollen and macroremains provided valuable insight on the mechanism of watershed processes. Copyright © 2006 John Wiley & Sons, Ltd.     

Mineralogical and geochemical investigations of sediment-source region changes in the Okinawa Trough during the past 100 ka (IMAGES core MD012404)

We present a mineralogical and geochemical study of core MD012404, retrieved from the central Okinawa Trough (OT) of the East China Sea. Our studies reveal that the sediment sources of the core have been changed through time during the past 100 ka. Our mineralogical proxies indicate that the sediments source from the Yangtze River correlates well sea-level changes before 24 ka. Our Ti/Al ratios otherwise indicate an increase of sediment supply from eastern Taiwan after 26 ka. The cooler climate of the Last Glacial Maximum (LGM, 23～19 ka) led to a reduction in fluvial sediments from the Yangtze River. However, subsequent climate warming (after ～19 ka) resulted in an abrupt increase in fluvial sediments. After the LGM, the Kuroshio intrusion flow into the OT may have increased. We also infer anomalous changes in eolian sources transported by winter monsoons during the LGM and at 80 ka based on an eolian mineralogical indicator (feldspar). We conclude that the sediment source of core MD012404 is primarily of terrestrial origins, but influenced by sea-level changes and variations in the East Asian monsoon.     

Southern Ocean control on the extent of denitrification in the southeast Pacific over the last 70 ka

Temporal changes in oceanic denitrification, the bacterial reduction of nitrate under suboxic conditions, highlight the potential importance of N inventory changes and the production of N₂O on the climate system. At the same time, the cause of the globally observed variation in denitrification remains unclear. High-resolution benthic foraminiferal oxygen isotope and bulk sediment nitrogen isotope records from ODP Site 1234 on the Chile Margin record integrated denitrification changes within the Peru–Chile Upwelling system over the last ∼70 ka. Denitrification changes in the southeast Pacific are coherent with Antarctic climate changes recorded by the Byrd ice core δ¹⁸O record, and lead northern hemisphere climate events. The southern-hemisphere character of the Chile margin δ¹⁵N record suggests that episodes of reduced denitrification in the SE Pacific represent times when more oxygen was supplied as the result of changes in the ventilation and preformed nutrient content of Subantarctic Mode Water (SAMW), which forms in the Subantarctic zone of the Southern Ocean and feeds into the low-latitude thermocline.     

Late Quaternary highstands at Lake Chilwa,Malawi: Frequency,timing and possible forcing mechanisms in the last 44 ka

The extensive shoreline deposits of Lake Chilwa, southern Malawi, a shallow water body today covering 600 km² of a basin of 7500 km², are investigated for their record of late Quaternary highstands. OSL dating, applied to 36 samples from five sediment cores from the northern and western marginal sand ridges, reveal a highstand record spanning 44 ka. Using two different grouping methods, highstand phases are identified at 43.7–33.3 ka, 26.2–21.0 ka and 17.9–12.0 ka (total error method) or 38.4–35.5 ka, 24.3–22.3 ka, 16.2–15.1 ka and 13.5–12.7 ka (Finite Mixture Model age components) with two further discrete events recorded at 11.01 ± 0.76 ka and 8.52 ± 0.56 ka. Highstands are comparable to the timing of wet phases from other basins in East and southern Africa, demonstrating wet conditions in the region before the LGM, which was dry, and a wet Lateglacial, which commenced earlier in the southern compared to northern hemisphere in East Africa. We find no evidence that wet phases are insolation driven, but analysis of the dataset and GCM modelling experiments suggest that Heinrich events may be associated with enhanced monsoon activity in East Africa in both timing and as a possible causal mechanism.     

OSL chronology of sand deposits and climate change of last 18 ka in Gurbantunggut Desert,northwest China

The development of the Gurbantunggut Desert is mainly controlled by the Westerly wind, and at present has little influence from Indian and Southeast Asian monsoons. A combined study using optically stimulated luminescence (OSL) dating, ground‐penetrating radar (GPR) surveys and climatic proxies analysis was carried out in the southern part of the desert. The chronology extends back to 18 ka and is constructed based on 16 OSL ages from boreholes in the linear dune body and the inter‐dune area. The chronology suggests that sand deposition in the last 18 ka experienced two rapid accumulation phases at 11 and 2.5 ka ago which were also evident from the GPR surveys. These periods relate to increased aridity in the region. Five climate phases are identified from the last 18 ka, based on the OSL chronology and climatic proxy analysis with grain size and magnetic susceptibility measurements. The deglacial period (18.3–10.4 ka) is characterized by climate instability and possible glacial melting events. The Holocene Optimum peaked 8.5 ka and terminated 3.6 ka ago, when the regional climate became arid. OSL samples from the dune body cluster around 2.5 ka, which indicates rapid advance/extension of dune bodies at this time. Copyright © 2011 John Wiley & Sons, Ltd.     

Precipitation history of the Lake Biwa area in central Japan over the last 145 ka

The fluvial quartz flux (FQF, g cm ^-2  ka ^-1 ) to Lake Biwa of central Japan is developed as a proxy of variations in palaeoprecipitation over the lake catchment. Lake Biwa sediments spanning the last c. 145 ka are characterized by 4 main intervals when the FQF values were significantly greater than 2 g cm ^-2  ka ^-1 , and 5 main periods during which FQF values were lower. Three of the intervals with high FQF values occur from c. 128 to 78 ka BP, with peak values at c. 122, 101 and 82 ka BP; the fourth of two narrow peaks exists between c. 48 and 35 ka BP. Three main periods with lower FQF values intervene between intervals of high FQF values, and two others lie before c. 128 ka BP and after c. 35 ka BP. The data imply that palaeoprecipitation over the lake catchment increased during the intervals of high FQF values, and decreased during the periods of lower FQF values. High FQF values between c. 48 and 35 ka BP are interpreted to reflect an effective runoff of meltwater from the surrounding mountains during the interstade of the last glaciation. Relatively low FQF values during the early Holocene are interpreted to reveal a sluggish northward retreat of the polar front in the North Pacific Ocean that suppressed the northward advance of the summer monsoonal front and regional precipitation. During the last interglaciation, the increasing trend of FQF values is interpreted to indicate a progressive expansion of the Sea of Japan related to the rise in global sea level, which increased moisture advection to, and precipitation within, the Lake Biwa region.     

The vegetation and climate of northwest Iberia over the last 14,000 years

A new pollen record from an upland lake in north-west Spain, Laguna de la Roya, spans the last ca 14,500 yrs and includes clear evidence of a Weichselian Lateglacial event correlative with the Younger Dryas. Pollen-climate response surfaces have been used to make quantitative reconstructions of palaeoclimate conditions at this and two other sites in the region. These reconstructions indicate that the climate was dry and cool during both the Late Weichselian and the Younger Dryas; in contrast, conditions during the Lateglacial Interstadial were relatively moist. During the early Holocene the climate was more continental in character than it has been for the last three millenia. Human activity has had a substantial impact upon the upland vegetation around Laguna de la Roya only during the last two millennia.