Orbital-scale environmental and climatic changes recorded in a new ∼200,000-year-long multiproxy sedimentary record from Padul, southern Iberian Peninsula

Padul is one of the few wetland sites in southern Europe and the Mediterranean region that exhibits an unusually large temporal span (>100 kyr) and continuous Quaternary sedimentary record. Previous core-based studies from Padul yielded paleoecological datasets (i.e., pollen and organic geochemistry), but with a poor age control that resulted in rather arbitrary climate inferences. Therefore, precise age control and a multidisciplinary approach is necessary to understand long-term regional environmental and climate change and the associated local response of the Padul wetland environment. Here we present a new long sediment record (Padul-15-05) from this wetland in the southern Iberian Peninsula with the aim of improving the age control of the sedimentary sequence and carrying out up-to-date high-resolution multiproxy analyses. In this study the age control is based on 61 AMS radiocarbon dates for the last ca. 50 kyr BP and on the extent of amino acid racemization (AAR) in mollusc shells extending back ∼118 kyr BP. No numerical ages are available for the bottom part of the core but the sediment accumulation rates (SAR) and the cyclostratigraphic analysis of the multiproxy data suggest that the core preserves a continuous record of the last ∼197 kyr (from late MIS 7 to present) with millennial-scale time resolution. Sedimentological (lithology, magnetic susceptibility, XRD, color), geochemical (XRF, TOC, C/N, % carbonate content) and paleontological (pollen, charophytes, gastropods) data show co-varying cyclical paleoenvironmental changes linked to orbital-scale climatic variability. Silicon, magnetic susceptibility (MS) and total organic carbon (TOC) data show periodicities between ∼26.2–19.6 kyr linked to insolation, which is strongly dominated by precession cycles at this latitude. High values of Si and MS data have been related to high siliciclastic/detrital input from Sierra Nevada range during minima in insolation due to enhanced soil weathering/erosion during regional aridity and lower forest cover recorded by the arboreal pollen, which could also be favored by a minor biogenic productivity. In addition, warm climate conditions during maxima in insolation mostly resulted in negative precipitation/evapotranspiration balance and low lake levels, while cold glacial and stadial periods were mainly characterized by positive precipitation/evapotranspiration balance, and therefore, high lake levels. The improved chronology of the Padul sedimentary sequence along with a multiproxy study permitted us to better relate environmental and vegetation changes to climatic events and to demonstrate how both local (i.e., lake level, sedimentation) and regional (i.e., vegetation) environments responded to orbital-scale climate changes

Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

High-reso CE to lution pollen analysis, charcoal, non-pollen palynomorphs and magnetic susceptibility have been analyzed in the sediment record of a peat bog in Sierra Nevada in southern Iberia. The study of these proxies provided the reconstruction of vegetation, climate, fire and human activity of the last ∼4500 cal yr BP. A progressive trend towards aridification during the late Holocene is observed in this record. This trend is interrupted by millennial- and centennial-scale variability of relatively more humid and arid periods. Arid conditions are recorded between ∼4000 and 3100 cal yr BP, being characterized by a decline in arboreal pollen and with a spike in magnetic susceptibility. This is followed by a relatively humid period from ∼3100 to 1600 cal yr BP, coinciding partially with the Iberian-Roman Humid Period, and is indicated by the increase of Pinus and the decrease in xerophytic taxa. The last 1500 cal yr BP are characterized by several centennial-scale climatic oscillations. Generally arid conditions from ∼450 to 1300 CE, depicted by a decrease in Pinus and an increase in Artemisia, comprise the Dark Ages and the Medieval Climate Anomaly. Since ∼ 1300 to 1850 CE pronounced oscillations occur between relatively humid and arid conditions. Four periods depicted by relatively higher Pinus coinciding with the beginning and end of the Little Ice Age are interrupted by three arid events characterized by an increase in Artemisia. These alternating arid and humid shifts could be explained by centennial-scale changes in the North Atlantic Oscillation and solar activity

Holocene summer temperature reconstruction based on a chironomid record from Sierra Nevada, southern Spain

This study was supported by projects CGL2013-47038-R, CGL2017-85415-R and PID2021-125619OB-C21/C22, funded by the Ministerio de Ciencia e Innovación of Spain, the Agencia Estatal de Investigación and the Fondo Europeo de Desarrollo Regional FEDER MCIN/AEI/10.13039/501100011033/FEDER, UE”; Junta de Andalucía I + D + i Junta de Andalucía 2020 Retos P-20-00059, UGR-FEDER B-RNM-144-UGR18, UGR-FEDER A-RNM-336-UGR20, Project cofinanced by FEDER and LifeWatch-Eric LifeWatch-2019-10-UGR-01 and the research group RNM-190 (Junta de Andalucía). RSA acknowledges several travel grants from Northern Arizona University to support this work. JC thanks the Ministerio de Ciencia e Innovación of Spain for the Juan de la Cierva Formación postdoctoral fellowship. ALA acknowledges the predoctoral fellowship BES-2018-084293 provided by the MCIN/AEI/10.13039/501100011033/. CLB acknowledges the European Union for her Marie Sklodowska-Curie grant agreement number 892487 under Horizon 2020 funds. LJ acknowledges the Ministry of Universities of Spain for her Margarita Salas grant (MS2021-204) financed by the European Union -Next Generation EU funds.Obtaining accurate temperature reconstructions from the past is crucial in understanding the consequences of changes in external climate forcings, such as orbital-scale insolation or multidecadal to centennial-scale variability on the climate system and the environment. In addition, these reconstructions help in comprehending the amplitude of natural temperature changes in the past, which can assist in evaluating the amplitude and rate of recent anthropogenic global warming. Here we present the first detailed Holocene mean July air temperature reconstruction based on chironomid assemblages from sediments retrieved from Laguna de Río Seco, an alpine lake in Sierra Nevada, southern Spain. Coldest climate conditions are recorded during the last glacial maximum and the last deglaciation. Warming occurred in the Early Holocene and warmest summer temperature conditions and the Holocene thermal maximum (HTM) occurred in the interval roughly between 9000 and 7200 cal yr BP, concurrent with summer insolation maxima. Rapid cooling of ∼1.5 °C occurred after the warmest maximum and between ∼7200 and 6500 cal yr BP, and temperatures stabilized between ∼6500 and 3000 cal yr BP. A further cooling began ∼3000 cal yr BP and culminated with coldest summer conditions during the Dark Ages (DA) and Little Ice Age (LIA) at ∼1550 cal yr BP (∼400 CE) and ∼200 cal yr BP (∼1750 CE), respectively. This cooling temperature trend was interrupted by warmer conditions during the Iberian-Roman Humid Period (IRHP) ∼2000 cal yr BP and during the Medieval Climate Anomaly (MCA) at ∼1000 cal yr BP. Our reconstruction shows a greater than two-degree cooling during the Middle and Late Holocene, agreeing with global mean surface temperature (GMST) reconstructions. Modern climate warming (MCW) during summer exceeds the two-degree Celsius forecasted for the future due to anthropogenic greenhouse gases, suggesting that recent warming is amplified at high elevations. Alpine environments and the biodiversity contained there are thus in danger if the observed temperature trend continues in the next decades.Ministerio de Ciencia e Innovación of Spain CGL2013-47038-R, CGL2017-85415-R, PID2021-125619OB-C21/C22Agencia Estatal de InvestigaciónFondo Europeo de Desarrollo Regional FEDER MCIN/AEI/10.13039/501100011033/FEDER, UEJunta de Andalucía P-20-00059, UGR-FEDER B-RNM-144-UGR18, UGR-FEDER A-RNM-336-UGR20FEDERLifeWatch-Eric LifeWatch-2019-10-UGR-01Research group RNM-190 (Junta de Andalucía)Northern Arizona UniversityMinisterio de Ciencia e Innovación of SpainMCIN/AEI/10.13039/501100011033/ BES-2018-084293Horizon 2020 European Union Marie Sklodowska-Curie 892487European Union -Next Generation EU funds MS2021-20

Laguna Seca sediments reveal environmental and climate change during the latest Pleistocene and Holocene in Sierra Nevada, southern Iberian Peninsula

This study was supported by the I + D + i projects CGL2013-47038- R, CGL2017-85415-R, PID2019-1049449GB-I00, and PID2021- 125619OB-C21/C22 funded by Ministerio Ciencia e Innovación/Agencia Estatal de Investigación/ 10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa”, I + D + i projects A-RNM-336-UGR20 and P20_00059 of the action “Proyectos I + D + i del Programa Operativo FEDER - Junta de Andalucía - UGR” and the research group RNM-190. This research is part of the project “Thematic Center on Mountain Ecosystem & Remote sensing, Deep learning- AI e-Services University of Granada-Sierra Nevada” (LifeWatch-2019- 10-UGR-01), which has been co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action line. José Carrión was supported by the I + D + I project PID2019-1049449 GB-I00 funded by MCIN/AEI/ 10.13039/501100011033/ and FEDER “Una manera de hacer Europa” and the fellowship 20788/PI/18 of Fundación Séneca. We thank Javier Jaimez for his help with the core drilling in Laguna Seca and Alejandro Navarro and Aurora Baquera for the sediment sampling. ALA acknowledges the predoctoral fellowship BES- 2018-084293 provide by the MCIN/ AEI/ 10.13039/5011000110 33/. CLB acknowledges the European Union for her Marie Sklodowska-Curie grant agreement number 892487 under Horizon 2020 funds. JC acknowledges the Ministerio de Ciencia e Innovación of the Spanish Government for the grant number FJC2020-044215-I of the Juan de la Cierva Formación postdoctoral program.Sedimentation in most glacial lakes and wetlands in the Sierra Nevada (southern Iberian Peninsula) began after the last deglaciation and since the Younger Dryas (YD)-Early Holocene (EH) transition. Therefore, until now, studies on older sedimentary records were lacking in this alpine area, which limits the paleoenvironmental and paleoclimatic information to the Holocene. In this study, we studied palynomorphs from the alpine record from Laguna Seca (LS), the longest and oldest (∼18,000 cal yr BP = 18 kyr) sedimentary record in the Sierra Nevada to investigate the response of forests and lake environments in the western Mediterranean area to climate changes and human impact during the latest Pleistocene and Holocene. The deepest lake conditions occurred during the last deglaciation, indicated by the occurrence of Pediastrum algae, which showed highest abundances during the Heinrich Stadial 1 (HS1) and Bølling-Allerød (B-A) transition. Xerophyte herbs such as Artemisia, Ephedra, and Amaranthaceae were highest during the late B-A and YD indicating regional aridity. Poaceae (grasses) were maxima in the B-A and EH, probably indicating expansion in the barren areas after deglaciation. Maximum in temperature and humidity during the EH and cooling and aridification in the Middle (MH) and Late Holocene (LH) are indicated by the changes in the abundance of deciduous Quercus and Pinus forest species. Botryococcus algae increased during the Early Holocene, while the rest of the algae almost vanished, which could indicate that the lake became very productive but shallower until 8.2 kyr. The lake level lowered and became seasonal in the Middle-Late Holocene transition, coinciding with the regional climate aridification. Microcharcoal analysis done on the palynological preparations agrees with the vegetation changes, showing maxima in the EH and MH, related with the maximum in regional forest occurrence, and a decrease in the LH when the Mediterranean vegetation, and thus fuel availability, diminished. This record shows evidence of anthropogenic impact in the last centuries by cultivation, reforestation, cattle grazing, enhanced erosion and eutrophication.I + D + i projects CGL2013-47038- R, CGL2017-85415-R, PID2019-1049449GB-I00, and PID2021- 125619OB-C21/C22 funded by Ministerio Ciencia e Innovación/Agencia Estatal de Investigación/ 10.13039/501100011033/ and Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa”I + D + i projects A-RNM-336-UGR20 and P20_00059 of the action “Proyectos I + D + i del Programa Operativo FEDER - Junta de Andalucía - UGR” and the research group RNM-190Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action lineI + D + I project PID2019-1049449 GB-I00 funded by MCIN/AEI/ 10.13039/501100011033/ and FEDER “Una manera de hacer Europa” and the fellowship 20788/PI/18 of Fundación SénecaPredoctoral fellowship BES- 2018-084293 provide by the MCIN/ AEI/ 10.13039/5011000110 33/European Union for her Marie Sklodowska-Curie grant agreement number 892487 under Horizon 2020 fundsMinisterio de Ciencia e Innovación of the Spanish Government for the grant number FJC2020-044215-I of the Juan de la Cierva Formación postdoctoral progra

Paleohydrological dynamics in the Western Mediterranean during the last glacial cycle

This study was supported by the project B-RNM-144-UGR18 of the action "Proyectos I+D+i del Programa Operativo FEDER 2018 -Junta de Andalucia-UGR", the projects CGL2013-47038-R and CGL201785415-R, of the "Ministerio de Economia y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER", and the research group RNM-190 (Junta de Andalucia). A.G.-A. was also supported by a Marie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration of the European Commission (NAOSIPUK. Grant Number: PIEF-GA-2012-623027) and by a Ram ' on y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economia y Competividad). J.C. acknowledges the postdoctoral funding provided by the Academy of Finland (project number 316702). J.L.T. hosted the NAOSIPUK project (PIEFGA-2012-623027) at the University of Glasgow. A.L.-A PhD is funded by BES-2018-084293 (Ministerio de Economia y Competividad). M.J.R.R. acknowledges the postdoctoral funding by the European Research Council (ERC-2017-ADG-788616). This study was supported by an ERC Consolidator Grant (STEEPclim) to D.S. (Grant Agreement No. 647035). E.S. is supported by the DFG Cluster of Excellence 2077 >The Ocean Floor -Earth's Uncharted Interface < at MARUM. We thank Ralph Kreutz for analytical support.The transitional regions between the low and high latitudes of the Northern Hemisphere are highly vulnerable to future climate change yet most of the current climate models usually diverge in their projections. To better understand the dynamics in these regions, the reconstruction of past hydrological fluctuations and precipitation patterns is of paramount importance to accurately constrain present and future climate scenarios. In this study, we investigated paleohydrological dynamics in the western Mediterranean region, a transitional zone between low-mid latitudes and Atlantic - Mediterranean realms. We reconstruct precipitation and moisture source changes during the last -35 ka in order to propose the potential mechanisms driving these oscillations. To do so, we use hydrogen isotopes from sedimentary leaf waxes, more specifically the C31 n-alkane homologue, and a precipitation proxy based on previously published pollen data from a sedimentary core (Padul-15-05) in southern Iberia (Padul wetland -37-N). With this combination we disentangle the coupled effect of precipitation amount and source on the hydrogen isotopic signature of the studied C31 n-alkane record. Our results show three main periods characterized by different precipitation patterns. Low precipitation, mainly linked to a significant contribution from an isotopically-enriched Mediterranean precipitation source, occurred from -30 to -15.5 ka BP and during the last -5 ka, whereas enhanced precipitation with a predominant isotopically-depleted Atlantic precipitation source prevailed from -15.5 to -5 ka BP. This latter stage is here defined as the Western Mediterranean Humid Period (WMHP). In addition, some occasional millennial-scale opposite precipitation patterns can be observed during these climatically distinct periods. These changes in the source of precipitation were likely coupled to a shift in the main rainy season from winter, when Atlantic precipitation prevailed, to late winter-early spring, when the contribution of Mediterranean moisture is higher. Comparison between the studied mid-latitude terrestrial Padul-15-05 core and a low-latitude marine record offshore of northwestern Africa shows clear long-term synchronous responses of both western Mediterranean precipitation and western African monsoon systems to northern Hemisphere atmospheric dynamics, ultimately controlled by orbital forcing and ice-sheets fluctuations.action "Proyectos I+D+i del Programa Operativo FEDER 2018 -Junta de Andalucia-UGR" B-RNM-144-UGR18Ministerio de Economia y Competitividad of Spain CGL2013-47038-R CGL201785415-RJunta de Andalucia RNM-190Marie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration of the European Commission (NAOSIPUK) PIEF-GA-2012-623027Spanish Government (Ministerio de Economia y Competividad) RYC-2015-18966Academy of FinlandEuropean Commission 316702NAOSIPUK project at the University of Glasgow PIEFGA-2012-623027Ministerio de Economia y Competividad BES-2018-084293European Research Council (ERC)European Commission ERC-2017-ADG-788616ERC Consolidator Grant (STEEPclim) 647035DFG Cluster of Excellence 2077 >The Ocean Floor -Earth's Uncharted Interface < at MARUMEuropean Commissio

Paleohydrological dynamics in the Western Mediterranean during the last glacial cycle

The transitional regions between the low and high latitudes of the Northern Hemisphere are highly vulnerable to future climate change yet most of the current climate models usually diverge in their projections. To better understand the dynamics in these regions, the reconstruction of past hydrological fluctuations and precipitation patterns is of paramount importance to accurately constrain present and future climate scenarios. In this study, we investigated paleohydrological dynamics in the western Mediterranean region, a transitional zone between low-mid latitudes and Atlantic - Mediterranean realms. We reconstruct precipitation and moisture source changes during the last -35 ka in order to propose the potential mechanisms driving these oscillations. To do so, we use hydrogen isotopes from sedimentary leaf waxes, more specifically the C31 n-alkane homologue, and a precipitation proxy based on previously published pollen data from a sedimentary core (Padul-15-05) in southern Iberia (Padul wetland -37-N). With this combination we disentangle the coupled effect of precipitation amount and source on the hydrogen isotopic signature of the studied C31 n-alkane record. Our results show three main periods characterized by different precipitation patterns. Low precipitation, mainly linked to a significant contribution from an isotopically-enriched Mediterranean precipitation source, occurred from -30 to -15.5 ka BP and during the last -5 ka, whereas enhanced precipitation with a predominant isotopically-depleted Atlantic precipitation source prevailed from -15.5 to -5 ka BP. This latter stage is here defined as the Western Mediterranean Humid Period (WMHP). In addition, some occasional millennial-scale opposite precipitation patterns can be observed during these climatically distinct periods. These changes in the source of precipitation were likely coupled to a shift in the main rainy season from winter, when Atlantic precipitation prevailed, to late winter-early spring, when the contribution of Mediterranean moisture is higher. Comparison between the studied mid-latitude terrestrial Padul-15-05 core and a low-latitude marine record offshore of northwestern Africa shows clear long-term synchronous responses of both western Mediterranean precipitation and western African monsoon systems to northern Hemisphere atmospheric dynamics, ultimately controlled by orbital forcing and ice-sheets fluctuations.Peer reviewe

Post-glacial evolution of alpine environments in the western Mediterranean region : The Laguna Seca record

In an effort to understand how alpine environments from the western Mediterranean region responded to climate variations since the last glacial-interglacial transition, a detailed chronological control and sedimentological analysis, supported by magnetic susceptibility, total organic carbon and C/N data, were carried out on the sedimentary record of Laguna Seca (LS). This is a latitudinal and altitudinally (2259 masl) key alpine wetland site located in the easternmost area of the Sierra Nevada, southern Iberian Peninsula, where sediments accumulated during Heinrich Stadial 1, Bolling-Allerod (B-A) and the Younger Dryas (YD) previously unrecorded in alpine Sierra Nevada. Climate controlled sedimentation in LS and three coarse-grained and one fine-grained facies association are differentiated, which help us decipher the paleoenvironmental evolution of LS: (1) subaerial cohesionless debris flows during a paraglacial stage; (2) till or nival diamicton during a small glacier/nivation hollow stage; (3) massive mudstone by suspension settling of clays into standing water during a lacustrine stage; and (4) frost-shattering breccia deposited inside the lacustrine stage, probably during the YD, and linked to a periglacial substage. The development of a previously existing small glacial cirque during the Last Glacial Maximum (LGM) in the LS basin at an elevation between 2500 and 2300 m could be supported by the important availability of slope sediments glacially-conditioned such as debris flows, reworked by paraglacial slope processes during the first deglaciation stages, confirming previous studies of landforms in the catchment area and the LGM-Equilibrium Line Altitude estimation above 2400 masl in Sierra Nevada. Mean sediment accumulation rates in the LS sedimentary units (4.21 and 0.28 mm/yr during the paraglacial small glacier/nivation stage and the lacustrine stage, respectively) confirm that geomorphic activity accelerated just after glaciers retreated due to a slope adjustment and high availability of glacially conditioned sediments. An abrupt change in paleoenvironmental and paleoclimatic conditions occurred in LS at ~ 15.7 cal kyr BP. This change was probably due to an increase in temperature and precipitation in the western Mediterranean region during the B-A. At LS, this resulted in significant ice-melt, forming a deep-water lake in LS with important organic matter contribution until the end of the Early Holocene (except in the YD when the lake level probably dropped), but elsewhere a general glacier recession in the Sierra Nevada and an expansion of the Mediterranean forest in the southern Iberian Peninsula. Finally, the general long-term aridification that occurred during the Middle Holocene until the present in the western Mediterranean region triggered an important environmental change transforming LS into an ephemeral wetland with an increase in aquatic productivity.Peer reviewe

Evidences of the Blake and Iceland Basin magnetic excursions in southeastern Iberia and chronological implications for the Padul sedimentary record

Acknowledgments This study was supported by the project B-RNM-144-UGR18 and ARNM- 336-UGR20 of the action “Proyectos I + D + i del Programa Operativo FEDER 2018 - Junta de Andalucía-UGR”, the projects CGL2013-47038-R and CGL2017-85415-R, of the “Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER”, and the research group RNM-190 (Junta de Andalucía), and the projects P18-RT-871 and Retos P20_00059 of Junta de Andalucia. A.G.-A. was also supported by a Ram´on y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economía y Competividad). A.L.-A PhD is funded by BES-2018-084293 (Ministerio de Economía y Competividad). We thank the Paleomagnetic Laboratory CCiTUB-Geo3Bcn CSIC for the support on paleomagnetic analysis. LV and EB thank the Geomodels Research Institute (UB). We are very grateful to two anonymous reviewers and to the editor Christian Zeeden.The Padul-15-05 sediment core provides an exceptional perspective of the paleoenvironmental and climate change in the Western Mediterranean region for the last ca. 200 kyr. However, even though a robust chronology mainly relying on radiometric dating is available for the last 50 ka, the chronology for the older sediments is not yet fully resolved. Ages for the bottom part of the core (>21 m) were previously inferred from amino-acid racemization dating and sediment accumulation rates. In this work, we provide a more accurate chronology for the older part (>100 kyr) of the Padul-15-05 sediment core record based on the recognition of past Earth's magnetic excursions. We identify an interval prone of reversed polarity samples close to MIS-5e/5 d transition that we correlate to the Blake geomagnetic excursion (116.5 kyr–112 kyr). In addition, we identify an interval of low inclinations and two reversed samples that we interpret as the Iceland Basin geomagnetic excursion (192.7 kyr–187.7 kyr: wide scenario of VGP <40°). Our new results, which include IRM acquisition curves that contribute to understand the magnetic mineralogy, enhances the robustness of the age model for the Padul-15-05 sedimentary sequence by adding an independent age dataset with new accurate tie-points. Our refined age control together with the available paleoenvironmental and paleoclimate multiproxy data provide insightful information to unveil the response of the western Mediterranean environments to regional environmental and climate change.Project B-RNM-144-UGR18 and ARNM- 336-UGR20 of the action “Proyectos I + D + i del Programa Operativo FEDER 2018 - Junta de Andalucía-UGR”Projects CGL2013-47038-R and CGL2017-85415-R, of the “Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER”Research group RNM-190 (Junta de Andalucía)Projects P18-RT-871 and Retos P20_00059 of Junta de AndaluciaRamón y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economía y Competividad)Funded by BES-2018-084293 (Ministerio de Economía y Competividad

A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees.

Morellón, Mario et al.A review of selected, well-dated, multiproxy paleoclimatic records (lacustrine, dendrochronological, geomorphological) characterizes the main environmental changes occurred in the Southern Pyrenees during the last millennium. Warmer and relatively arid conditions prevailed during the Medieval Climate Anomaly (MCA, <1300 AD), with a significant development of xerophytes and Mediterranean vegetation and limited deciduous tree formations (mesophytes). The Little Ice Age (LIA, 1300-1800 AD) was generally colder and moister, with an expansion of deciduous taxa and cold-adapted mountainous conifers. Two major phases occurred within this period: (i) a transition MCA-LIA, characterized by fluctuating, moist conditions and relatively cold temperatures (ca. 1300 and 1600 AD); - (ii) a second period, characterized by coldest conditions and higher humidity, coinciding with maximum (recent) glacier advances (ca. 1600-1850 AD). After the LIA a warming and more arid phase started coinciding with glacier retreat, and interrupted by a short-living cooling episode during the late 19th to early 20th centuries. Some records suggest a response to solar activity with colder and slightly moister conditions during solar minima. Centennial-scale hydrological fluctuations are in phase with reconstructions of NAO variability, which appears to be the main forcing for humidity in the region during the last millennium. © 2011 Author(s).This research has been funded by the Spanish InterMinistry of Science and Technology (CICYT), through the projects LIMNOCAL (CGL2006-13327-C04-01), GLOB-ALKARST (REN2003-09130-C02-02), GRACCIE-CONSOLIDER (CSD2007-00067), DINAMO (CGL2009-645-07992) and CRYOMONT (CGL2010-19724). Additional support was provided by the Spanish National Parks Agency through the project HORDA (083/2009). M. Morellón is supported by a Postdoctoral fellowship funded by the Spanish Ministry of Education and Science through FECYT (Spanish Foundation for Science and Technology). A. Perez-Sanz is supported by a pre-doctoral fellowship funded by the Regional Aragonese Government and A. Moreno acknowledges the “Ramón y Cajal” postdoctoral program for funding.Peer Reviewe