Holocene Palaeoenvironmental Changes in North-West Europe: Climatic Implications and the Human Dimension

Effective climate change adaptation requires a thorough understanding of whether and how affected populations perceive climatic and environmental changes. Existing research has been inconclusive regarding the consistency of these perceptions compared to objective meteorological indicators. Moreover, no systematic comparison has been done for the perception of discrete environmental events such as floods or erosion. This study relies on novel panel survey data of approximately 1700 households residing along the Jamuna River in Bangladesh as well as on unique individual-level, satellite-based erosion data. It compares respondents’ perceptions of environmental events, namely riverbank erosion, and three climate change indicators, specifically long-term temperature change and changes in precipitation during wet and dry seasons, to objective measurements using satellite imagery and climatic time-series data (CRU TS). I find that long-term temperature change is perceived more accurately than long-term changes in precipitation. Given that educational attainment and climate change literacy among the study population are low, this indicates that global temperature increases are felt even by remote populations who have never heard the term climate change. Erosion is strongly overestimated, especially by those respondents who had been personally affected by it. Since human behavior is guided by perceptions rather than objective data, this has important policy implications, underlining the importance of considering people’s perceptions if the goal is to assist them in adapting to environmental changes.

rom the plagues of biblical times to the HIV pandemic of today, infectious diseases have played an indisputably major role in human history. The continual expansion of human populations since prehistoric times has led to successive invasions of the human population by increasing numbers of different pathogens. Today many people's worries about emerging pathogens have been sharply focused by the Ebola virus outbreak in Kikwit, Zaire, and by Lyme disease and hantavirus outbreaks throughout the United States (Garrett 1994, Levins et al. 1994). In this article, we examine the infectious diseases of humans from an ecological perspective. Understanding pathogens at the population level is as important in disease prevention and control as understanding pathogens at the microscopic or molecular level. Three ecological processes are crucial in determining the impact, persistence, and spread of pathogens and parasites: the size and spatial distribution of the host population, the movement of infected and susceptible hosts and vectors, and the nutritional status of the human host population. Although medical ad-

Vegetation and land-surface hydrology are intrinsically linked under long-term climate change. This paper aims to evaluate the dynamics of potential natural vegetation arising from 21st century climate change and its possible impact on the water budget of the Hanjiang River basin in China. Based on predictions of the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC-SRES) A1 scenario from the PRECIS (Providing Regional Climates for Impact Studies) regional climate model, changes in plant functional types (PFTs) and leaf area index (LAI) were simulated via the Lund-Potsdam-Jena dynamic global vegetation model. Subsequently, predicted PFTs and LAIs were employed in the Xinanjiang vegetation-hydrology model for rainfall–runoff simulations. Results reveal that future long-term changes in precipitation, air temperature and atmospheric CO2 concentration would remarkably affect the spatiotemporal distribution of PFTs and LAIs. These climate-driven vegetation changes would further influence regional water balance. With the decrease in forest cover in the 21st century, plant transpiration and evaporative loss of intercepted canopy water will tend to fall while soil evaporation may rise considerably. As a result, total evapotranspiration may increase moderately with a slight increase in annual runoff depth. This indicates that, for long-term hydrological prediction, climate-induced changes in terrestrial vegetation cannot be neglected as the terrestrial biosphere plays an important role in land-surface hydrological responses.

Troublesome Reflection:Racism as the Blind Spot in the Scientific Critique of Race Charles C. Roseman A Troublesome Inheritance: Genes, Race and Human History, by Nicholas Wade. New York: Penguin Press, 2013. 288 pp. 978-1-5942-0446-3 (hardcover). US $27.95. In A Troublesome Inheritance, Nicholas Wade seeks to use advances in genomics and comparative human biology to revivify hereditarian racialist notions about the ways in which differences among human societies are shaped by evolutionary forces acting on genetic variation. The arc of the argument consists of three claims: (1) human evolution has produced some unspecified number of races; (2) differences among these races in social dispositions have a strong genetic component; and (3) an oppressive academic environment keeps this kind of research out of the intellectual mainstream. These claims form the core of a world view that I refer to as "hereditarian racialism." Recent examples of this genera include The Bell Curve (Herrnstein and Murray 1994) and Race, Evolution, and Behavior (Rushton 1995), with examples extending back for some time (e.g., Grant 1970 [1912]). None of these claims are true. The book is neither good popular science writing nor all that new or interesting by the standards of the hereditarian racialist literature. (Rushton [1995] and Miele and Sarich [2005] are far more interesting examples of this genera.) Troublesome Inheritance, however, is a useful foil for a critical examination of the mainline scientific critique of hereditarian racialism, which, as it stands, is weak and scattered. To recuperate a useful scientific critique of race, we need to come to grips with ways in which the political processes of racism have shaped human organisms over the last few hundred years. Genomic Variation and Human Population History and Structure Contrary to Wade's assertion, all parties to controversies surrounding human variation agree that humans show genomic and phenotypic variation that is structured in geographic space, through time, and across many social divisions. The disagreement is over how best to describe and model the evolutionary causes of this variation. Ignoring for the moment the large changes in the distribution of human genetic variation over the last few centuries (more on that below under Evolutionary Consequences of Racism), we can build a range of evolutionary models and statistically compare their fit to available genomic data. [End Page 189] In this idiom, racial models of variation like the one advocated in Troublesome Inheritance take the form of something like the tree diagram in Figure 1A (Hunley et al. 2009; Long and Kittles 2003). Groups within a race share common ancestry with one another more recently than they do with groups in other races. In contrast, most narrative accounts of recent human evolution feature population fissioning and founding events reflecting the movement of groups into different regions (previously occupied or not; see, e.g., Henn et al. 2012). Out-of-Africa dispersals and the spread of agriculture are two examples of these kinds of events. In this case, we might start with an estimate of a tree of patterns of common ancestry among groups under the expectation that groups with more recent common ancestry should be more genetically similar than those with distant common ancestry (Long and Kittles 2003; Long et al. 2009; Pickrell and Pritchard 2012). We can then add in admixture (episodic mixing of previously isolated groups) and gene flow between groups to produce a more elaborate model (Hunley et al. 2009; Pickrell and Pritchard 2012; Prüfer et al. 2014). The result is something like the elaborate model sketched out in Figure 1B, which is far and away the best fit to population genomic data. The relative importance of the different processes that make up these models are still a matter for further research, but it is certain that the racial model is a poor fit to the data and does not allow us to generate new and interesting questions. Click for larger view View full resolution Figure 1. Models of population structure and history. Black lines indicate evolving lineages and recency of common ancestry, with time going from left to right. The numbered tips of the lineages are operationally defined groups of individuals. The length of a line segment reflects...

Do farmers care about climate change? Evidence from five major grain producing areas of China

This review addresses the causes of observed climate variations across the industrial period, from 1750 to present. It focuses on long-term changes, both in response to external forcing and to climate variability in the ocean and atmosphere. A synthesis of results from attribution studies based on palaeoclimatic reconstructions covering the recent few centuries to the 20th century, and instrumental data shows how greenhouse gases began to cause warming since the beginning of industrialization, causing trends that are attributable to greenhouse gases by 1900 in proxy-based temperature reconstructions. Their influence increased over time, dominating recent trends. However, other forcings have caused substantial deviations from this emerging greenhouse warming trend: volcanic eruptions have caused strong cooling following a period of unusually heavy activity, such as in the early 19th century; or warming during periods of low activity, such as in the early-to-mid 20th century. Anthropogenic aerosol forcing most likely masked some global greenhouse warming over the 20th century, especially since the accelerated increase in sulphate aerosol emissions starting around 1950. Based on modelling and attribution studies, aerosol forcing has also influenced regional temperatures, caused long-term changes in monsoons and imprinted on Atlantic variability. Multi-decadal variations in atmospheric modes can also cause long-term climate variability, as apparent for the example of the North Atlantic Oscillation, and have influenced Atlantic ocean variability. Long-term precipitation changes are more difficult to attribute to external forcing due to spatial sparseness of data and noisiness of precipitation changes, but the observed pattern of precipitation response to warming from station data supports climate model simulated changes and with it, predictions. The long-term warming has also led to significant differences in daily variability as, for example, visible in long European station data. Extreme events over the historical record provide valuable samples of possible extreme events and their mechanisms.

During the last few years, the debate over the changes in the global average temperature has been one of the most important political issues. A better understanding of the effects of the temperature increase on other variables is one of the main challenges in climate. In the last IPCC report, due in part to the limited rainfall data in the tropics, there is no reliable conclusion about the observed and expected long-term precipitation changes in association with the global temperature increase. Since water resources are essential for energy generation and food production in the Department of Antioquia, Colombia, a better understanding of changes in rainfall in the long term becomes a vital tool for decision making. This research presents an assessment of rain variability at different temporal and spatial scales over Colombia, and more specifically over Antioquia. The data used was corresponds to long-term records of 86 rain gauges, in addition to 9 temperature stations, and TRMM precipitation products. The use of in-situ rain gauge information allows focusing on a spatial scale useful not only for a general understanding of precipitation changes but also for engineering and other practical applications. Analyses reveal that while there are no long-term trends in precipitation at the monthly or longer timescales, relatively short-lived extreme events show long-term changes in intensity and frequency. Results show that the shorter the duration of the intense events, the higher the magnitude of the increasing intensity trend. Similarly, for more intense events, the trends are also larger and more significant from a statistical point of view. Analysis of temperatures shows a clear relationship with extreme precipitation events with scaling features explained via the Clausius-Clapeyron relation, controlling the intensification of precipitation. The long-term rainfall trends are compared with modeling results from the different scenarios of a small set of CMIP runs given that most models do not adequately represent Colombia´s precipitation climatology. The results indicate a substantial reduction of return period of extreme events with implications in engineering: the current hydraulic designs would be obsolete in less than 50 years if the increment in the frequency of intense events is not considered in the design.

Расположенные в Юго-Восточном Забайкалье на границе с Монголией в зоне недостаточного увлажнения и резко континентального климата Торейские озера, представленные соединенными между собой бессточными озерами Барун-Торей и Зун-Торей, периодически наполняются, затапливая десятки тысяч гектаров территории, а спустя несколько лет полностью высыхают. Анализ изменений их уровня воды с начала 1700-х до 1960-х годов, выполнен преимущественно на качественном уровне на основе картографических материалов XVIII века, свидетельств путешественников и ученых, фондовых геологических и гидрометеорологических данных. За последние 55 лет использовались инструментальные данные и снимки искусственных спутников Земли. Показано, что средняя годовая температура воздуха в Юго-Восточном Забайкалье с середины XX века повысилась в среднем на 2°С. До начала 1990-х годов это повышение обусловливалось потеплением в холодный период года, а позже – ростом температуры теплого периода. В частности, это сказалось на существенном увеличении испаряемости в последние 20 лет. В южных районах исследуемой территории, в том числе в котловине Торейских озер, произошло значимое уменьшение атмосферных осадков, обусловившее, наряду с увеличением испаряемости, усиление аридизации этих районов. В многолетнем режиме осадков преобладают внутривековые циклы продолжительностью 25–30 лет. Цикличность характерна и для многолетних изменений стока рек. Наиболее устойчивыми за весь период наблюдений за стоком в Забайкалье, начиная с конца XIX века, являются 25–30-летние циклы. Цикличность атмосферных осадков и речного стока обусловила соответствующий уровенный режим Торейских озер. Отмечаемая слабая выраженность влажной фазы цикла, которая должна была начаться примерно с 2011 года, обусловлена усилением аридизации южных районов исследуемой территории в последние годы. Сделан вывод, что Торейские озера в полной мере могут считаться индикатором многолетних изменений увлажненности Юго-Восточного Забайкалья и Северо-Восточной Монголии. The Torey Lakes, represented by the interconnected Barun-Torey and Zun-Torey lakes in Southeastern Transbaikalia on the Russia-Mongolia border, have global ecological significance. We aimed to assess the dependence of the Torey Lakes' water level fluctuations on climatic factors by using cartographic materials, scientists’ evidence and observations, and a geological and hydrometeorological databases from the early 1700s to the 1960s, and instrumental data and satellite imagery over the past 55 years. The average annual air temperature from the middle of the 20th century increased by an average of 2°C. Until the early 1990s this growth was due to warming during the cold period; after the 1990s due to an increase in temperature during the warm period, causing significantly higher evaporation over the past 20 years. We revealed a significant decrease in atmospheric precipitation in the south of the study area, including the Torey Lakes depression, causing an increase in evaporation and aridization in these areas. However, a reliable relationship between long-term changes in atmospheric precipitation and air temperature was not found. Intrasecular cycles of 25–30 years prevail in the multiyear precipitation regime. Cyclicity is also typical for long-term changes in rivers' runoff. The cyclical nature of atmospheric precipitation and river runoff determined the Torey Lakes level regime. We noted a weak manifestation of the wet phase of the cycle due to the increased aridization in recent years. We concluded that the Torey Lakes can be considered an indicator of long-term changes in moisture in Southeastern Transbaikalia and Northeastern Mongolia.

Response of the Amazon rainforest to late Pleistocene climate variability

The results of the analysis of long-term changes in precipitation over the Siberian region territory for the past 50 years (from 1969 to 2018) based on the observations of 62 weather stations are presented. The study of long-term changes in annual and seasonal average values of total precipitation was carried out using interannual variation curves, as well as linear trends and their intensity (mm/decade).

Abstract. Here we present the first empirical evidence for changes in groundwater drought associated with anthropogenic warming in the absence of long-term changes in precipitation. Analysing standardised indices of monthly groundwater levels, precipitation and temperature, using two unique groundwater level data sets from the Chalk aquifer, UK, for the period 1891 to 2015, we show that precipitation deficits are the main control on groundwater drought formation and propagation. However, long-term changes in groundwater drought are shown to be associated with anthropogenic warming over the study period. These include increases in the frequency and intensity of individual groundwater drought months, and increases in the frequency, magnitude and intensity of episodes of groundwater drought, as well as an increasing tendency for both longer episodes of groundwater drought and for an increase in droughts of less than 1 year in duration. We also identify a transition from a coincidence of episodes of groundwater drought with precipitation droughts at the end of the 19th century, to an increasing coincidence with both precipitation droughts and with hot periods in the early 21st century. In the absence of long-term changes in precipitation deficits, we infer that the changing nature of groundwater droughts is due to changes in evapotranspiration (ET) associated with anthropogenic warming. We note that although the water tables are relatively deep at the two study sites, a thick capillary fringe of at least 30 m in the Chalk means that ET should not be limited by precipitation at either site. ET may be supported by groundwater through major episodes of groundwater drought and, hence, long-term changes in ET associated with anthropogenic warming may drive long-term changes in groundwater drought phenomena in the Chalk aquifer. Given the extent of shallow groundwater globally, anthropogenic warming may widely effect changes to groundwater drought characteristics in temperate environments.

The amount of genetic diversity in a population is determined by demographic and selection events in its history. Human populations which exhibit greatly reduced overall genetic diversity, presumably resulting from severe bottlenecks or founder events, are particularly interesting, not least because of their potential to serve as valuable resources for health studies. Here, we present an unexpected case, the human population of Nias Island in Indonesia, that exhibits severely reduced Y chromosome (non-recombining portion of the Y chromosome [NRY]) and to a lesser extent also reduced mitochondrial DNA (mtDNA) diversity as compared with most other populations from the Asia/Oceania region. Our genetic data, collected from more than 400 individuals from across the island, suggest a strong previously undetected bottleneck or founder event in the human population history of Nias, more pronounced for males than for females, followed by subsequent genetic isolation. Our findings are unexpected given the island's geographic proximity to the genetically highly diverse Southeast Asian world, as well as our previous knowledge about the human history of Nias. Furthermore, all NRY and virtually all mtDNA haplogroups observed in Nias can be attributed to the Austronesian expansion, in line with linguistic data, and in contrast with archaeological evidence for a pre-Austronesian occupation of Nias that, as we show here, left no significant genetic footprints in the contemporary population. Our work underlines the importance of human genetic diversity studies not only for a better understanding of human population history but also because of the potential relevance for genetic disease-mapping studies.

About 850,000 years ago, the period of the glacial cycles changed from 41,000 to 100,000 years. This mid-Pleistocene climate transition has been attributed to global cooling, possibly caused by a decrease in atmospheric carbon dioxide concentrations. However, evidence for such cooling is currently restricted to the cool upwelling regions in the eastern equatorial oceans, although the tropical warm pools on the western side of the ocean basins are particularly sensitive to changes in radiative forcing. Here we present high-resolution records of sea surface temperatures spanning the past 1.75 million years, obtained from oxygen isotopes and Mg/Ca ratios in planktonic foraminifera from the western Pacific warm pool. In contrast with the eastern equatorial regions, sea surface temperatures in the western Pacific warm pool are relatively stable throughout the Pleistocene epoch, implying little long-term change in the tropical net radiation budget. Our results challenge the hypothesis of a gradual decrease in atmospheric carbon dioxide concentrations as a dominant trigger of the longer glacial cycles since 850,000 years ago. Instead, we infer that the temperature contrast across the equatorial Pacific Ocean increased, which might have had a significant influence on the mid-Pleistocene climate transition.

Contemporary climate dynamics of the circum-Caribbean region are characterised by significant precipitation variability on interannual and interdecadal timescales controlled primarily by El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO). However, our understanding of pre-industrial climate variability in the region is hampered by the sparse geographic distribution of palaeoclimate archives. Here, we present a high-resolution reconstruction of effective precipitation for Barbuda since the mid-16th century, based on biostratigraphic and stable isotope analyses of fossil ostracods and gastropods recovered from lake sediment cores from Freshwater Pond, the only freshwater lake on the island. We interpret episodic fluctuations in shell accumulation in the sediment record to represent changes in the balance between precipitation and evaporation during the ‘Little Ice Age’ (LIA; ~1400–1850 CE) and Industrial (1850–present) periods. Comparisons between indices of reconstructed ENSO and AMO variability, the abundance of the freshwater gastropod Pyrgophorus parvulus and the δ18O records from ostracod calcite suggest that the relative influence of ENSO and AMO on long-term rainfall patterns in Barbuda has changed over the last 400 years. Our findings are in agreement with other high-resolution palaeoclimate studies that suggest that long-term changes in effective precipitation during the LIA were much more variable, temporally and spatially, than previously suggested.

Understanding long-term changes in precipitation is crucial for climate research, as it plays a key role in shaping water availability, ecosystem stability, and the occurrence of extreme weather phenomena. However, it is a well-established fact that different data types (station, gridded, and reanalyses) can yield varied results in statistical analyses of extremes and trends. This study investigates the long-term changes in precipitation characteristics across various data sources, focusing on the European land area. We analyze station data from the European Climate Assessment and Dataset (ECA&D) project. Station data interpolated onto a regular grid are represented by the gridded version of the ECA dataset [European Daily High-Resolution Observational Gridded Dataset (E-OBS)] and the Rainfall Estimates on a Gridded Network (REGEN) and the reanalyses data include NCEP/NCAR, the Twentieth Century Reanalysis (20CR) dataset, and the high-resolution fifth generation ECMWF atmospheric reanalysis (ERA5). The objective is to explore the seasonal trends in precipitation total amounts, intensity, and probability from 1961 to 2010, with a focus on winter and summer. The trends of winter precipitation totals and probabilities show a substantial north–south gradient, with positive trends in the north. All data sources underestimate the spatial extent of positive trends and overestimate the spatial extent of negative trends compared to ECA&D. Precipitation intensity trends lack clear geographic patterns, but statistically significant positive trends prevail in northeastern Europe. In general, a similar trend pattern is evident within the ECA&D, E-OBS, and ERA5 datasets. Conversely, the NCEP/NCAR and 20CR reanalyses exhibit the most significant disparities in trends for all precipitation characteristics.