Mean July Temperature Research Articles

Pilgrimstad revisited - a multi-proxy reconstruction of Early/Middle Weichselian climate and environment at a key site in central Sweden

The site Pilgrimstad in central Sweden has often been cited as a key locality for discussions of ice-free/ice-covered intervals during the Early and Middle Weichselian. Multi-proxy investigations of a recently excavated section at Pilgrimstad now provide a revised picture of the climatic and environmental development between similar to 80 and 36 ka ago. The combination of sedimentology, geochemistry, OSL and 14C dating, and macrofossil, siliceous microfossil and chironomid analyses shows: (i) a lower succession of glaciofluvial/fluvial, lacustrine and glaciolacustrine sediments; (ii) an upper lacustrine sediment sequence; and (iii) Last Glacial Maximum till cover. Microfossils in the upper lacustrine sediments are initially characteristic for oligo- to mesotrophic lakes, and macrofossils indicate arctic/sub-arctic environments and mean July temperatures > 8 degrees C. These conditions were, however, followed by a return to a low-nutrient lake and a cold and dry climate. The sequence contains several hiatuses, as shown by the often sharp contacts between individual units, which suggests that ice-free intervals alternated with possible ice advances during certain parts of the Early and Middle Weichselian.

Modern pollen assemblages of surface samples and their relationships to vegetation and climate in the northeastern Qinghai-Tibetan Plateau, China

We use a data set of 86 surface pollen samples from moss polsters and surface soils from northeastern Qinghai-Tibetan Plateau to explore the relationship between modern pollen assemblages and contemporary vegetation patterns. The samples span seven main vegetation zones from east to west: mountain forest, alpine shrub, alpine meadow, temperate steppe, steppe desert, shrub/semi-shrub desert and desert. Principal components analysis (PCA) was used to determine the relationships between modern pollen, vegetation, and regional climatic gradients. The results show that the major vegetation communities occurring today in the northeastern Qinghai-Tibetan Plateau can be clearly differentiated by their modern pollen assemblages. The representation of surface pollen varies with genera and species. For instance, relative to Betula, a low representation of Picea and Cupressaceae was found in the forest zone; Artemisia, Chenopodiaceae and Ephedraceae had high representation values, while Cyperaceae, and Nitraria showed values in the middle range, and Poaceae, Asteraceae, Tamarixaceae, Calligonum, Polygonaceae, Ranunculaceae, Fabaceae, Scrophulariaceae and Primulaceae had low representation values. Rosaceae have low representation values in the sampling sites in alpine shrub community where the dominant plant species are Potentilla fruticosa and Potentilla glabra. PCA results indicated a high correlation between the modern pollen assemblages and mean annual precipitations (MAP) and July temperature ( T july). The Artemisia/Chenopodiaceae (A/C) ratio is sensitive to variations in MAP in this region and is a useful tool for qualitative and semi-quantitative palaeoclimate reconstruction on the northeastern Qinghai-Tibetan Plateau.

Dendrochronology in the High Arctic: July air temperatures reconstructed from annual shoot length growth of the circumarctic dwarf shrub Cassiope tetragona

The instrumental Arctic climate record is both temporally and spatially limited. Therefore, there is a need for reliable climate proxies to increase knowledge of past and future Arctic climate change. Annual shoot length increase of the circumarctic dwarf shrub species Cassiope tetragona represents such a new climate proxy. We measured annual shoot length increase of 32 plant samples of the circumarctic dwarf shrub species C. tetragona using the presence of wintermarksepta within the stems, resulting in a 169 year growth chronology (1840–2008) for a High Arctic site on Svalbard. This is the longest growth chronology for dwarf shrub species produced up to now. Relationships between climate and Cassiope growth were investigated through correlative, response function and forward stepwise multiple regression analysis. July average air temperature was found to be the most important factor determining growth, by itself capable of explaining 41% of the variance in shoot growth between 1912 and 2008. The second best predictors were previous year September precipitation sums and average air temperatures, along with several previous growth parameters. A multiple regression model explaining growth with current July and previous year September temperature, combined with previous growth of lag 1, 2 and 5 years as predictors explains 70% of the observed variance in growth. July temperatures and previous year September precipitation sums alone explain 59% of the variance in standardized growth. Mean July air temperature was reconstructed for the period between 1876 and 2007 by a growth-temperature transfer model, using current and following year’s growth. The estimated temperatures correlated well with measured temperatures over the calibration (1912–1959) and verification (1960–2007) period: R 2 = 0.34 and R 2 = 0.47, respectively. The instrumental record (1912–2008) extended with these reliable mean July temperature estimates (1876–1911) reveals a significant warming trend on Svalbard since 1876 of 0.07 °C decade −1 on average. This study shows that the climate–growth relationships in C. tetragona, its longevity, its annual resolution, the availability of (sub)fossil fragments in tundra soil cores and its circumartic distribution make it a very valuable tool for climate reconstructions beyond the instrumental record and in areas lacking meteorological data, throughout the Arctic.

Species responses to fire, climate and human impact at tree line in the Alps as evidenced by palaeo‐environmental records and a dynamic simulation model

Summary 1. We use high‐resolution records of macroscopic charcoal and plant remains from sediments of a lake in the Swiss Alps (Gouillé Rion, 2343 m a.s.l.) to reconstruct local fire variability and vegetation dynamics over the last 12 000 years. 2. Species response to fire variability and to summer temperature was obtained by combining regression analyses between contiguous series of plant macrofossils, macroscopic charcoal and an available reconstruction of past summer temperature. 3. With a dynamic landscape vegetation model (LandClim), we simulated fire regimes using two levels of ignition frequency and moisture availability to disentangle the role of climate vs. humans on fire occurrence. The simulation results show that human disturbance was relevant in controlling the fire variability and are in agreement with pollen evidence of human impact from previous studies from Gouillé Rion. 4. Our results show that fire is a natural disturbance agent in the tree line ecotone. Biomass availability controlled the fire regime until increased land use and anthropogenic fire during the past 4000 years changed species composition and vegetation structure close to the tree line. 5. Important species at the tree line ecotone such as Pinus cembra greatly benefitted from periods with temperature above the modern mean July temperature, if anthropogenic fire disturbance was not too severe, such as during the Bronze Age (c. 4000 cal. years bp). 6. When mean July temperatures were lower than modern mean July values, Juniperus nana and Larix decidua were at an advantage over P. cembra. With increasing anthropogenic fire, open lands with J. nana replaced L. decidua and P. cembra forest stands. 7. Synthesis. Fire activity was low to moderate during the early and mid‐Holocene. Intensified land use coupled with fire occurrence since the Bronze Age (c. 4000 cal. years bp) had a larger impact on species composition near the tree line than climate change. Although climate change will alter vegetation composition, future dynamics of mountain forests will be co‐determined by anthropogenic fire. For example, high fire variability may impede upslope establishment of forests in response to climatic warming as expected for this century, with serious implications for forest diversity.

Tree-ring-based May–July mean temperature history for Lüliang Mountains, China, since 1836

As a consequence of recent global warming and its social impact, regional climate change is attracting an increasing amount of attention from scientists. A May–July temperature proxy extending back to 1836 was developed from tree-ring width of Chinese pine (Pinus tabulaeformis Carr.) found in the middle Luliang Mountains, northern China. Correlations with climatic data from six nearby meteorological stations range from −0.58 to −0.65, indicating a strong response of tree-ring index to May–July mean temperatures, which were subsequently reconstructed. The reconstruction captures 45% (F=38.474, P<0.001) of the regional variance in the instrumental data over the calibration period 1955–2003. Reconstructed warm and cold periods were verified by additional temperature reconstructions based on tree-ring data from northern China. In addition, the reconstruction was significantly correlated with May–July mean temperatures from 13 other meteorological stations in northern China, suggesting that our reconstruction is also representative of north-central China. The warming trend during the second half of the 20th century is seen in the reconstruction, but only the 1994–2002 mean temperature seems unprecedented over the whole reconstructed period.

Developing a modern pollen–climate calibration data set for Norway

Bjune, A. E., Birks, H. J. B., Peglar, S. M. &amp; Odland, A. 2010: Developing a modern pollen–climate calibration data set for Norway. Boreas, Vol. 39, pp. 674–688. 10.1111/j.1502‐3885.2010.00158.x. ISSN 0300‐9483.Modern pollen–climate data sets consisting of modern pollen assemblages and modern climate data (mean July temperature and mean annual precipitation) have been developed for Norway based on 191 lakes and 321 lakes. The original 191‐lake data set was designed to optimize the distribution of the lakes sampled along the mean July temperature gradient, thereby fulfilling one of the most critical assumptions of weighted‐averaging regression and calibration and its relative, weighted‐averaging partial least‐squares regression. A further 130 surface samples of comparable taphonomy, taxonomic detail and analyst became available as a result of other projects. These 130 samples, all from new lakes, were added to the 191‐lake data set to create the 321‐lake data set. The collection and construction of these data sets are outlined. Numerical analyses involving generalized linear modelling, constrained ordination techniques, weighted‐averaging partial least‐squares regression, and two different cross‐validation procedures are used to asses the effects of increasing the size of the calibration data set from 191 to 321 lakes. The two data sets are used to reconstruct mean July temperature and mean annual precipitation for a Holocene site in northwest Norway and a Lateglacial site in west‐central Norway. Overall, little is to be gained by increasing the modern data set beyond about 200 lakes in terms of modern model performance statistics, but the down‐core reconstructions show less between‐sample variability and are thus potentially more plausible and realistic when based on the 321‐lake data set.

The Effect of Ecological Factors on the Indexes of Yield Property Equation and Quantitative Analysis

The mechanism of action of ecological factors affecting crop growth and development was complicated. In order to study the relationships between ecological factors and the indexes of yield property equation and determine the main ecological factors affecting yield, using 3-yr field experimental results for different yielding spring maize ( Zea mays L.) populations and the relative meteorological observation data in Huadian of Jilin Province in China, and analyzing on the base of the yield property equation (MLAI × D × MNAR × HI = EN × GN × GW), the main ecological factors were screened, and further mechanisms of action affecting yield were analyzed. Stepwise regression analysis showed that yield was affected mainly by effective accumulated temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, and the sunshine hour before and after silking. In yield property equation, four indexes of MLAI, growth days, ear number and grain number (total grain number) affected principally yield, the ecological factors affecting predominantly yield were effective accumulated temperature, daily mean temperature, daily mean minimum temperature, daily mean maximum temperature in July, the ratios of growth days, rainfall, accumulated temperature, and sunshine hours before and after silking. Combined with the two analytical methods, it could be deduced that the temperature and the allocated ratios before and after silking of ecological factors were the key factors to achieve high yield. Therefore, appropriate sowing data should be adjusted to achieve the suitable temperature indexes during the whole growth stage and the rational allocated ratios of ecological factors before and after silking.

A modern pollen–climate calibration set based on lake sediments from the Tibetan Plateau and its application to a Late Quaternary pollen record from the Qilian Mountains

AbstractAim Fossil pollen spectra from lake sediments on the Tibetan Plateau have been used for qualitative climate reconstruction, but no modern pollen–climate calibration set based on lake sediments is available to infer past climate quantitatively. This study aims to develop such a dataset and apply it to fossil data.Location The Tibetan Plateau, between 30 and 40° N and 87 and 103° E.Methods We collected surface sediments from 112 lakes and analysed them palynologically. The lakes span a wide range of mean annual precipitation (Pann; 31–1022 mm), mean annual temperature (Tann; −6.5 to 1 °C), and mean July temperature (TJuly; 2.6–19.7 °C). Redundancy analysis showed that the modern pollen spectra are characteristic of their respective vegetation types and local climate. Transfer functions for Pann, Tann and TJuly were developed with weighted averaging partial least squares. Model performance was assessed by leave‐one‐out cross‐validation.Results The root mean square errors of prediction (RMSEP) were 104 mm (Pann), 1.18 °C (Tann) and 1.17 °C (TJuly). The RMSEPs, when expressed as percentages of the gradient sampled, were 10.6% (Pann), 15.7% (Tann) and 11.9% (TJuly). These low values indicate the good performance of our models. An application of the models to fossil pollen spectra covering the last c. 50 kyr yielded realistic results for Luanhaizi Lake in the Qilian Mountains on the north‐eastern Tibetan Plateau (modern Pann 480 mm; Tann−1 °C). Tann and Pann values similar to present ones were reconstructed for late Marine Isotope Stage 3, with minimum values for the Last Glacial Maximum (c. 300 mm and 2 °C below present), and maximum values for the early Holocene (c. 70 mm and 0.5 °C greater than present).Main conclusions The modern pollen–climate calibration set will potentially be useful for quantitative climate reconstructions from lake‐sediment pollen spectra from the Tibetan Plateau, an area of considerable climatic and biogeographical importance.

Co‐variation of fish assemblages, flow regimes and other habitat factors in French rivers

Summary1. Using data from 270 minimally disturbed river sites distributed across France, we examined relationships between fish assemblages and four sets of explanatory variables representing climate, position in the river network, geomorphology and flow regime (temporal flow variation).2. Flow regimes, represented by 157 hydrological indices, were derived from 763 gauging stations representing unmodified flows. Principal components analysis was used to reduce the 157 indices to nine non‐redundant hydrological variables, and hydrological regionalisation was then used to transfer the hydrological variables to the sampling sites.3. Climate, position in the river network and geomorphology, collectively referred to as ‘habitat’ factors, and were represented by the variables mean January and July temperature, distance from source, mean flow and altitude and width, depth, slope, sediment size and % lotic habitat.4. Partial constrained ordination (pCCA) showed that hydrological variables individually explained 9.7% of the variability of fish assemblages, however the variation explained by the hydrological variables decreased to only 3.4% when the variation explained by the habitat variables was removed.5. Our study showed that co‐variation between hydrological and habitat variables need to be accounted for to avoid overestimating the importance of biological–hydrological relationships. Failing to do so may have important implications for the development of environmental flow prescriptions, as apparent biological responses to altered flow regimes are likely to be confounded by variation associated with habitat variability.

Record low surface air temperature at Vostok station, Antarctica

The lowest recorded air temperature at the surface of the Earth was a measurement of −89.2°C made at Vostok station, Antarctica, at 0245 UT on 21 July 1983. Here we present the first detailed analysis of this event using meteorological reanalysis fields, in situ observations and satellite imagery. Surface temperatures at Vostok station in winter are highly variable on daily to interannual timescales as a result of the great sensitivity to intrusions of maritime air masses as Rossby wave activity changes around the continent. The record low temperature was measured following a near‐linear cooling of over 30 K over a 10 day period from close to mean July temperatures. The event occurred because of five specific conditions that arose: (1) the temperature at the core of the midtropospheric vortex was at a near‐record low value; (2) the center of the vortex moved close to the station; (3) an almost circular flow regime persisted around the station for a week resulting in very little warm air advection from lower latitudes; (4) surface wind speeds were low for the location; and (5) no cloud or diamond dust was reported above the station for a week, promoting the loss of heat to space via the emission of longwave radiation. We estimate that should a longer period of isolation occur the surface temperature at Vostok could drop to around −96°C. The higher site of Dome Argus is typically 5–6 K colder than Vostok so has the potential to record an even lower temperature.

Calibrating vascular plant abundance for detecting future climate changes in Oregon and Washington, USA

We propose using future vascular plant abundances as indicators of future climate in a way analogous to the reconstruction of past environments by many palaeoecologists. To begin monitoring future short-term climate changes in the forests of Oregon and Washington, USA, we developed a set of transfer functions for a present-day calibration set consisting of climate parameters estimated, and species abundances measured, at 107 USDA Forest Service FIA (Forest Inventory and Analysis) Phase 3 plots. For each plot, we derived climate estimates from the Daymet model database, and we computed species abundance as quadrat frequency and subplot frequency. We submitted three climate variables (mean January temperature, MJAT; mean July temperature, MJUT; and mean annual precipitation transformed to natural logarithms, MANPt) to canonical correspondence analysis (CCA), and verified their importances in structuring the species frequency data. Weighted averaging-partial least squares regression (WA-PLS) provided the means for calculating six transfer functions. In all cases, based on performance statistics generated by leave-one-out cross-validation, we identified two-component WA-PLS models as the most desirable. The predictive abilities of our transfer functions are comparable to, or better than, those reported in the literature, probably due both data quality and statistical considerations. However, model overfitting as a result of spatial autocorrelation remains a possibility. The large errors associated with our MJAT transfer functions connote that even the highest amount of change in mean January temperature predicted for Oregon and Washington for 2010–2039 would be indistinguishable from current conditions. The higher predictions indicate that our MJAT transfer functions may be able to track climate changes by the 2040s. Our MJUT transfer functions can detect change in mean July temperature under the highest projection for 2010–2039. Our MANPt transfer functions will be of limited use until the 2070s, given the predictions of only slight changes in mean annual precipitation during the early part of the twenty-first century. Our MJAT and MANPt transfer functions may prove useful at the present time to verify relative climatic stability. Because the predicted climate values sometimes deviate substantially from the observed values for individual plots, our transfer functions are appropriate for monitoring climatic trends over the entire Pacific Northwest or large regions within it, not for assessing climate change at individual plots.

Research and Solutions: Effects of Climate and Institution Size on Greenhouse Gas Emissions from Colleges and Universities in the United States

Emissions of greenhouse gases (GHG) associated with buildings may constitute as much as 40 percent of total emissions by the United States. Data on GHG emissions for 238 institutions, including doctorate-granting universities, master's institutions, and baccalaureate colleges, were acquired from the American College & University Presidents' Climate Commitment (ACUPCC). A regression model that included gross building area, July mean temperature, and January mean low temperature was used to predict GHG emissions (R2 = 0.911). A similar model was developed for emissions as a function of full-time equivalent (FTE) students, but the fit was poorer (R2 = 0.693). The percentage of coal in the energy source for electric power generation was also a factor, with higher percentages resulting in higher emissions. Institutions with high percentages of coal as their electricity source also experienced low January temperatures, making it difficult to distinguish the effects of energy source from winter climate. For doct...

BACCHUS temperature reconstruction for the period 16th to 18th centuries from Viennese and Klosterneuburg grape harvest dates

In the scientific project “Klosterneuburg Wine and Climate Change in Lower Austria” (BACCHUS), we focused on developing a grape harvest date (GHD) time series for the period 1523–2007 in the area of and around Vienna, one of the northeasternmost regions in Europe where vines are grown professionally. Since grape harvest dates are strongly influenced by spring to (early) summer temperatures, especially in a vine‐growing region at a climatic border, we found highly significant correlation coefficients between homogenized multiple monthly mean temperatures at Vienna, Hohe Warte, and GHD. For example, correlation values reach −0.76 (p = 0.01) between GHD and April to July mean temperature or −0.79 (p = 0.01) between GHD and May to July mean temperature. This made it possible to reconstruct May to July mean temperatures, starting in 1523. The years from 1775 to 1850 were used as calibration period for determining the temperature sensitivity of GHD, as the running correlation coefficients (10 year moving window) were most pronounced in this period, varying between almost −1 and −0.7 (p = 0.05). We found warm decades in the 16th century, at the beginning of our series, which were as warm as the 1990s. Afterwards the mean May to July temperatures started to drop; the coldest decade of the record was from 1771 to 1780. A constant temperature increase for more than 30 years, as from the 1970s to the present, seems to be unprecedented during the last 470 years.

Last nine-thousand years of temperature variability in Northern Europe

Abstract. The threat of future global warming has generated a major interest in quantifying past climate variability on centennial and millennial time-scales. However, palaeoclimatological records are often noisy and arguments about past variability are only possible if they are based on reproducible features in several reliably dated datasets. Here we focus on the last 9000 years, explore the results of 36 Holocene pollen-based July mean and annual mean temperature reconstructions from Northern Europe by stacking them to create summary curves, and compare them with a high-resolution, summary chironomid-based temperature record and other independent palaeoclimate records. The stacked records show that the "Holocene Thermal Maximum" in the region dates to 8000 to 4800 cal yr BP and that the "8.2 event" and the "Little Ice Age" at 500–100 cal yr BP are the clearest cold episodes during the Holocene. In addition, a more detailed analysis of the last 5000 years pinpoints centennial-scale climate variability with cold anomalies at 3800–3000 and 500–100 cal yr BP, a long, warmer period around 2000 cal yr BP, and a marked warming since the mid 19th century. The colder (warmer) anomalies are associated with increased (decreased) humidity over the northern European mainland, consistent with the modern high correlation between cold (warm) and humid (dry) modes of summer weather in the region. A comparison with the key proxy records reflecting the main forcing factors does not support the hypothesis that solar variability is the cause of the late-Holocene centennial-scale temperature changes. We suggest that the reconstructed anomalies are typical of Northern Europe and their occurrence may be related to the oceanic and atmospheric circulation variability in the North Atlantic – North-European region.

Oxygen isotope fractionation in three freshwater ostracod species from early Holocene lacustrine tufa in northern Estonia

We quantified differences in oxygen isotope fractionation among three biostratigraphically important subfossil ostracod species (Metacypris cordata, Pseudocandona rostrata and Candonopsis kingsleii) from an early Holocene freshwater tufa layer in northern Estonia. Estimated mean δ18O values are −10.05‰ for M. cordata, −9.34‰ for C. kingsleii and −8.75‰ for P. rostrata. All three species exhibit positive offset from the weighted mean annual δ18O of contemporary precipitation (−10.7‰ in δ18OV-PDB) and from the mean δ18O value of authigenic tufa carbonate (−10.64‰) in the ostracod-bearing layer. Assuming that the known oxygen isotope fractionation in P. rostrata (+2.5‰) and M. cordata (+1.5‰) has remained constant over time, the theoretical δ18OV-SMOW of the early Holocene lake water was calculated to have been between −11.52 and −11.92‰, slightly less negative than the local Ordovician groundwater (−11.7 to −12.2‰). δ18O values of the tufa carbonate differ by +0.6 to +1.0‰ from the calculated theoretical isotope composition (δ18OV-PDB) of lake water, indicating that the tufa also did not precipitate in isotopic equilibrium with ambient waters. Results show that the greater the δ18O offset from the calculated, theoretical isotope composition of lake water for an ostracod species, the lower is its preferred mean July temperature. Both our data and earlier published results on δ18O values in Holocene lacustrine carbonates and ostracods from north-eastern Europe, display pronounced decreases in δ18O with an increase in latitude of the study site. This suggests that temperature-dependent, and therefore latitude-dependent isotopic composition of meteoric waters controlled the δ18O values in lacustrine tufa and ostracods throughout the Holocene.

Defining and Characterizing Coolwater Streams and Their Fish Assemblages in Michigan and Wisconsin, USA

AbstractCoolwater streams, which are intermediate in character between coldwater “trout” streams and more diverse warmwater streams, occur widely in temperate regions but are poorly understood. We used modeled water temperature data and fish assemblage samples from 371 stream sites in Michigan and Wisconsin to define, describe, and map coolwater streams and their fish assemblages. We defined coolwater streams as ones having summer water temperatures suitable for both coldwater and warmwater species and used the observed distributions of the 99 fish species at our sites to identify coolwater thermal boundaries. Coolwater streams had June‐through‐August mean water temperatures of 17.0–20.5°C, July mean temperatures of 17.5–21.0°C, and maximum daily mean temperatures of 20.7–24.6°C. We delineated two subclasses of coolwater streams: “cold transition” (having July mean water temperatures of 17.5–19.5°C) and “warm transition” (having July mean temperatures of 19.5–21.0°C). Fish assemblages in coolwater streams were variable and lacked diagnostic species but were generally intermediate in species richness and overlapped in composition with coldwater and warmwater streams. In cold‐transition streams, coldwater (e.g., salmonids and cottids) and transitional species (e.g., creek chub Semotilus atromaculatus, eastern blacknose dace Rhynichthys atratulus, white sucker Catostomus commersonii, and johnny darter Etheostoma nigrum) were common and warmwater species (e.g., ictalurids and centrarchids) were uncommon; in warm‐transition streams warmwater and transitional species were common and coldwater species were uncommon. Coolwater was the most widespread and abundant thermal class in Michigan and Wisconsin, comprising 65% of the combined total stream length in the two states (cold‐transition streams being more common than warm‐transition ones). Our approach can be used to identify and characterize coolwater streams elsewhere in the temperate region, benefiting many aspects of fisheries management and environmental protection.

The health of Arctic populations: Does cold matter?

The objective of the study was to examine whether cold climate is associated with poorer health in diverse Arctic populations. With climate change increasingly affecting the Arctic, the association between climate and population health status is of public health significance. The mean January and July temperatures were determined for 27 Arctic regions based on weather station data for the period 1961-1990 and their association with a variety of health outcomes assessed by correlation and multiple linear regression analyses. Mean January temperature was inversely associated with infant and perinatal mortality rate, age-standardized mortality rate from respiratory diseases, and age-specific fertility rate for teens and directly associated with life expectancy at birth in both males and females, independent of a variety of socioeconomic, demographic, and health care factors. Mean July temperature was also associated with infant mortality and mortality from respiratory diseases, and with total fertility rate. For every 10 degrees C increase in mean January temperature, the life expectancy at birth among males increased by about 6 years and infant mortality rate decreased by about 4 deaths/1,000 livebirths. Cold climate is significantly associated with higher mortality and fertility in Arctic populations and should be recognized in public health planning.

Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

Abstract. In this study a radiocarbon-dated pollen record from Lake Kotokel (52°47´ N, 108°07´ E, 458 m a.s.l.) located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate from about 15 kyr BP (1 kyr=1000 cal. yr) until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (~−38°C) and July (~12°C) temperatures and annual precipitation (~270–300 mm) values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8–14.7 kyr BP, during the Allerød Interstadial between 13.3–12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga) communities in the region is associated with a warmer and wetter-than-present climate (Tw~17–18°C, Tc~−19°C, Pann~500–550 mm) that occurred ca. 10.8–7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all climatic variables about 7–6.5 kyr BP. Our results demonstrate a gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel since that time.

Differentiation of MIS 9 and MIS 11 in the continental record: vegetational, faunal, aminostratigraphic and sea-level evidence from coastal sites in Essex, UK

Multidisciplinary investigations of the vegetational, faunal and sea-level history inferred from the infills of buried channels on the coast of eastern Essex have a direct bearing on the differentiation of MIS 11 and MIS 9 in continental records. New data are presented from Cudmore Grove, an important site on Mersea Island that can be linked to the terrace sequence of the River Thames. The vegetational history has been reconstructed from a pollen sequence covering much of the interglacial represented. The temperate nature of the climate is apparent from a range of fossil groups, including plant remains, vertebrates (especially the rich herpetofauna), molluscs and beetles, which all have strong thermophilous components. The beetle data have been used to derive a Mutual Climatic Range reconstruction, suggesting that mean July temperatures were about 2°C warmer than modern values for southeast England, whereas mean January temperatures may have been slightly colder. The sea-level history has been reconstructed from the molluscs, ostracods and especially the diatoms, which indicate that the marine transgression occurred considerably earlier in the interglacial cycle than at the neighbouring Hoxnian site at Clacton. There are a number of palynological similarities between the sequence at Cudmore Grove and Clacton, especially the presence of Abies and the occurrence of Azolla filiculoides megaspores. Moreover, both sites have yielded Palaeolithic archaeology, indeed the latter is the type site of the Clactonian (flake-and-core) industry. However, the sites can be differentiated on the basis of mammalian biostratigraphy, new aminostratigraphic data, as well as the differences in the sea-level history. The combined evidence suggests that the infill of the channel at Cudmore Grove accumulated during MIS 9, whereas the deposits at Clacton formed during MIS 11. The infill of a much later channel, yielding non-marine molluscs and vertebrates including Hippopotamus, appears to have formed during the Ipswichian (MIS 5e). This evidence is compared with other important sites of late Middle Pleistocene age in Britain and elsewhere on the continent and the importance of a multidisciplinary approach is stressed.

Palaeoenvironmental context of the Late‐glacial woolly mammoth (Mammuthus primigenius) discoveries at Condover, Shropshire, UK

AbstractIn 1986/1987 the remains of several mammoths, Mammuthus primigenius (Blumenbach), were discovered on the spoil heap of an actively working gravel pit at Condover, Shropshire, England. The discovery of the remains posed two questions that could be addressed by analyses of biological proxies. First, as none of the bones was found in situ it was necessary to confirm the stratum in which the remains occurred. Second, what was the environment in which these animals lived and died? A range of biological indicators was used to address these questions, including pollen, spore and algal, plant macrofossil, invertebrate, anuran and biological mineral analyses. Multivariate statistical analyses of palynological and Pediastrum data, along with evidence from the Coleopteran assemblages, support the attribution of the mammoth bones to a unit of dark grey clayey sandy silt, although they may have lived at the time of the overlying green detritus mud. The palaeobiological data supports the correlation of these sediments to the Devensian Late‐glacial. The mammoths entered this basin at the start of the Late‐glacial Interstadial (Greenland Interstadial 1e) (ca. 14 830—3930 cal. year BP; 12 300 ± 110 14C year BP) and became mired in soft cohesive sediments. Palaeotemperature reconstructions, based on the Coleopteran assemblages, from the time when the mammoths actually became mired, show that the climate was temperate with mean July temperatures between 15 and 19°C and mean January temperatures between −13 and +6°C. Biological indicators from the sediments encasing the mammoths indicate that the landscape surrounding the basin was treeless and dry, contrasting with rich vegetation within the basin itself that had possibly attracted the mammoths to the site. Evidence of sedimentary disturbance suggests that the mammoths caused large‐scale bioturbation of the deposits making palaeoenvironmental interpretations difficult. Fossils of terrestrial blowflies, carcass and dung beetles show that some of the decaying corpses must have lain exposed on the land surface for sufficient time for the soft parts to have rotted away and skin and bones to have become desiccated before many of them sank into the dark grey clayey sandy silt. Copyright © 2009 John Wiley &amp; Sons, Ltd.