Soil control on runoff response to climate change in regional climate model simulations

Simulations with seven regional climate models driven by a common control climate simulation of a GCM carried out for Europe in the context of the (European Union) EU-funded Prediction of Regional scenarios and Uncertainties for Defining European Climate change risks and Effects (PRUDENCE) project were analyzed with respect to land surface hydrology in the Rhine basin. In particular, the annual cycle of the terrestrial water storage was compared to analyses based on the 40-yr ECMWF Re-Analysis (ERA-40) atmospheric convergence and observed Rhine discharge data. In addition, an analysis was made of the partitioning of convergence anomalies over anomalies in runoff and storage. This analysis revealed that most models underestimate the size of the water storage and consequently overestimated the response of runoff to anomalies in net convergence. The partitioning of these anomalies over runoff and storage was indicative for the response of the simulated runoff to a projected climate change consistent with the greenhouse gas A2 Synthesis Report on Emission Scenarios (SRES). In particular, the annual cycle of runoff is affected largely by the terrestrial storage reservoir. Larger storage capacity leads to smaller changes in both wintertime and summertime monthly mean runoff. The sustained summertime evaporation resulting from larger storage reservoirs may have a noticeable impact on the summertime surface temperature projections

Escalating environmental summer heat exposure - a future threat for the European workforce

Heat exposure constitutes a major threat for European workers, with significant impacts on the workers' health and productivity. Climate projections over the next decades show a continuous and accelerated warming over Europe together with longer, more intense and more frequent heatwaves on regional and local scales. In this work, we assess the increased risk in future occupational heat stress levels using the wet bulb globe temperature (WBGT), an index adopted by the International Standards Organization as regulatory index to measure the heat exposure of working people. Our results show that, in large parts of Europe, future heat exposure will indeed exceed critical levels for physically active humans far more often than in today?s climate, and labour productivity might be largely reduced in southern Europe. European industries should adapt to the projected changes to prevent major consequences for the workers? health and to preserve economic productivity.Financial support for this work is provided by the HEAT-SHIELD Project (European Commission HORIZON 2020, research and innovation programme under the grant agreement 668786). The authors wish to thank the Swiss National Supercomputing Centre (CSCS) for providing the technical infrastructure

Prenatal Methylmercury Exposure and Developmental Outcomes: Review of the Evidence and Discussion of Future Directions

I conducted a review of the published literature to assess the strength of the evidence for an association between prenatal exposure to methylmercury (MeHg) and subsequent child development. I identified 12 studies on this subject published since 1980. Of these, 3 were longitudinal studies—2 conducted in the Seychelle Islands, and 1 in the Faroe Islands. Nine were cross-sectional studies conducted in different countries where seafood, a source of MeHg, constituted a major part of the diet. The ages of the children studied ranged from 2 weeks to 12 years. The results of the longitudinal studies were contradictory. Researchers in the Faroe Islands identified an association between MeHg exposure and developmental effects, whereas those in the Seychelle Islands identified no such association. This inconsistency was mirrored in the results of the cross-sectional studies where there were some positive and some negative findings. It was concluded that it was not possible from currently available data to determine whether there is an association between prenatal MeHg exposure and adverse developmental effects in children. In advance of future research, consideration should be given to resolving the uncertainties surrounding exposure assessment and outcome measurement, as both elements varied between studies. It was suggested that questions of exposure assessment would benefit from the application of an expert review process. Outcome assessment would benefit from the development of theoretically based measures of specific aspects of cognitive functioning to replace the relatively crude measures of attainment and IQ currently employed in most studies. This would assist in the development of classic longitudinal studies by allowing repeated assessment over the full age range and providing data that are more readily interpretable and comparable between studies

Use of expert elicitation to assign weights to climate and hydrological models in climate impact studies

Various methods are available for assessing uncertainties in climate impact studies. Among such methods, model weighting by expert elicitation is a practical way to provide a weighted ensemble of models for specific real-world impacts. The aim is to decrease the influence of improbable models in the results and easing the decision-making process. In this study both climate and hydrological models are analysed, and the result of a research experiment is presented using model weighting with the participation of six climate model experts and six hydrological model experts. For the experiment, seven climate models are a priori selected from a larger EURO-CORDEX (Coordinated Regional Downscaling Experiment - European Domain) ensemble of climate models, and three different hydrological models are chosen for each of the three European river basins. The model weighting is based on qualitative evaluation by the experts for each of the selected models based on a training material that describes the overall model structure and literature about climate models and the performance of hydrological models for the present period. The expert elicitation process follows a three-stage approach, with two individual rounds of elicitation of probabilities and a final group consensus, where the experts are separated into two different community groups: a climate and a hydrological modeller group. The dialogue reveals that under the conditions of the study, most climate modellers prefer the equal weighting of ensemble members, whereas hydrological-impact modellers in general are more open for assigning weights to different models in a multi-model ensemble, based on model performance and model structure. Climate experts are more open to exclude models, if obviously flawed, than to put weights on selected models in a relatively small ensemble. The study shows that expert elicitation can be an efficient way to assign weights to different hydrological models and thereby reduce the uncertainty in climate impact. However, for the climate model ensemble, comprising seven models, the elicitation in the format of this study could only re-establish a uniform weight between climate models

Mid-Holocene European climate revisited: new high-resolution regional climate model simulations using pollen-based land-cover

International audienceLand-cover changes have a clear impact on local climates via biophysical effects. European land cover has been affected by human activities for at least 6000 years, but possibly longer. It is thus highly probable that humans altered climate before the industrial revolution (AD1750e1850). In this study, climate and vegetation 6000 years (6 ka) ago is investigated using one global climate model, two regional climate models, one dynamical vegetation model, pollen-based reconstruction of past vegetation cover using a model of the pollen-vegetation relationship and a statistical model for spatial interpolation of the reconstructed land cover. This approach enables us to study 6 ka climate with potential natural and reconstructed land cover, and to determine how differences in land cover impact upon simulated climate. The use of two regional climate models enables us to discuss the robustness of the results. This is the first experiment with two regional climate models of simulated palaeo-climate based on regional climate models. Different estimates of 6 ka vegetation are constructed: simulated potential vegetation and recon- structed vegetation. Potential vegetation is the natural climate-induced vegetation as simulated by a dynamical vegetation model driven by climate conditions from a climate model. Bayesian spatial model interpolated point estimates of pollen-based plant abundances combined with estimates of climate- induced potential un-vegetated land cover were used for reconstructed vegetation. The simulated potential vegetation is heavily dominated by forests: evergreen coniferous forests dominate in northern and eastern Europe, while deciduous broadleaved forests dominate central and western Europe. In contrast, the reconstructed vegetation cover has a large component of open land in most of Europe. The simulated 6 ka climate using reconstructed vegetation was 0-5° C warmer than the pre-industrial (PI) climate, depending on season and region. The largest differences are seen in north-eastern Europe in winter with about 4e6 C, and the smallest differences (close to zero) in southwestern Europe in winter. The simulated 6 ka climate had 10-20% more precipitation than PI climate in northern Europe and 10 -20% less precipitation in southern Europe in summer. The results are in reasonable agreement with proxy-based climate reconstructions and previous similar climate modelling studies. As expected, the global model and regional models indicate relatively similar climates albeit with regional differences indicating that, models response to land-cover changes differently

Methylmercury exposure in a subsistence fishing community in Lake Chapala, Mexico: an ecological approach

<p>Abstract</p> <p>Background</p> <p>Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated.</p> <p>Methods</p> <p>Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age.</p> <p>Results</p> <p>Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm). Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations.</p> <p>Conclusions</p> <p>Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.</p

Human impacts and their interactions in the Baltic Sea region

Coastal environments, in particular heavily populated semi-enclosed marginal seas and coasts like the Baltic Sea region, are strongly affected by human activities. A multitude of human impacts, including climate change, affect the different compartments of the environment, and these effects interact with each other. As part of the Baltic Earth Assessment Reports (BEAR), we present an inventory and discussion of different human-induced factors and processes affecting the environment of the Baltic Sea region, and their interrelations. Some are naturally occurring and modified by human activities (i.e. climate change, coastal processes, hypoxia, acidification, submarine groundwater discharges, marine ecosystems, non-indigenous species, land use and land cover), some are completely human-induced (i.e. agriculture, aquaculture, fisheries, river regulations, offshore wind farms, shipping, chemical contamination, dumped warfare agents, marine litter and microplastics, tourism, and coastal management), and they are all interrelated to different degrees. We present a general description and analysis of the state of knowledge on these interrelations. Our main insight is that climate change has an overarching, integrating impact on all of the other factors and can be interpreted as a background effect, which has different implications for the other factors. Impacts on the environment and the human sphere can be roughly allocated to anthropogenic drivers such as food production, energy production, transport, industry and economy. The findings from this inventory of available information and analysis of the different factors and their interactions in the Baltic Sea region can largely be transferred to other comparable marginal and coastal seas in the world