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[en] This publication proposes a synthesis of the various actions undertaken by the Climate-Environment-Energy GIS (Group of Scientific Interest) with the objectives of promoting a dialogue between disciplines which were not or few working together, and of applying interdisciplinarity as an essential approach to researches on climate change. A first part addresses climate-economy interactions (carbon emissions, soil use). A second part addresses multidisciplinary approaches to the study of extreme events (scientific stakes and deadlocks, how to survey and model a rare event, space and time scales, assessment of coupled processes in the dynamics of extreme events, how to detect trends in extreme events). The third part addresses impact, adaptation and mitigation regarding ecosystems and water resources (benefits and drawbacks of scale downgrading, use of ecological indicators for a better understanding of impacts of past climate, improvement of the understanding and modelling of mechanisms of climate impacts on biodiversity, ecosystem and hydrology, quantification and management of uncertainty for climate adaptation and mitigation). The fourth part addresses the relationship between climate change and health (climate physical parameters, atmosphere composition and air quality, impacts related to climate change). The fifth part addresses the construction of interdisciplinarity within the Climate GIS. Several sheets present projects
[en] This study is based on monitoring data obtained from the Airparif measurement network, and partly on other investigations related to the possible influence of a reduction of nitrogen oxide emissions on a reduction of nitrogen dioxide levels in the ambient air. Thus, it aimed at providing a theoretical description of photochemical equilibria met in urban areas (more particularly the relationship between NO2 and NOx), an analysis of linear functions describing relationships between NO2 and NOx concentration according to different and complementary approaches (three statistical approaches and two analytic approaches), a calculation of NOx concentration reductions to be achieved in order to comply with reference values. For this calculation, different methods are used based on emission measurements by Airparif, on the establishment of an empirical relationship between concentrations, on the determination of the right necessary emission reduction rate to comply with objectives, and on an assessment of the implications of a strategy of NOx emission reduction on ozone concentrations
[en] Climate change contributes to a rapid and deep modification of the environment. In the same time, other factors such as population increase, ageing or urbanization increase the vulnerability to various environmental and health risks. Chains of complex interactions are impacting populations' health and well-being. Developing prevention measures is an asset to reduce the health impacts of present climate change (through adaptation measures) and to limit the intensity of future impacts (through mitigation measures). Mitigation will result in major changes in several sectors, for instance housing, transports or agriculture. Taking into account the potential health impacts is important to avoid choices impairing human health, and to maximize health co-benefits. In this paper we propose a reflection on how present and future climate change in France challenges epidemiology and public health in the next few years. While many questions remain unanswered, there is a consensus on the importance of the links between climate change and human health, that can be summarized into three points: 1) climate change already impacts human health, 2) adaptation and mitigation are needed to reduce those impacts, 3) adaptation and mitigation can rely on immediate measures that would be beneficial for health and for climate. An integrated and interdisciplinary approach is essential to tackle the complexity of the issue, of its implications for public health, for research, surveillance and intervention. (authors)
[en] A new high-resolution regional climate change ensemble has been established for Europe within the World Climate Research Program Coordinated Regional Down-scaling Experiment (EURO-CORDEX) initiative. The first set of simulations with a horizontal resolution of 12.5 km was completed for the new emission scenarios RCP4.5 and RCP8.5 with more simulations expected to follow. The aim of this paper is to present this data set to the different communities active in regional climate modelling, impact assessment and adaptation. The EURO-CORDEX ensemble results have been compared to the SRES A1B simulation results achieved within the ENSEMBLES project. The large-scale patterns of changes in mean temperature and precipitation are similar in all three scenarios, but they differ in regional details, which can partly be related to the higher resolution in EURO-CORDEX. The results strengthen those obtained in ENSEMBLES, but need further investigations. The analysis of impact indices shows that for RCP8.5, there is a substantially larger change projected for temperature-based indices than for RCP4.5. The difference is less pronounced for precipitation-based indices. Two effects of the increased resolution can be regarded as an added value of regional climate simulations. Regional climate model simulations provide higher daily precipitation intensities, which are completely missing in the global climate model simulations, and they provide a significantly different climate change of daily precipitation intensities resulting in a smoother shift from weak to moderate and high intensities. (authors)
[en] After having outlined the necessity of a development of climate services with users, this publication highlights the strengthening of existing and emerging climate services (the Drias portal, the interdisciplinary group of national contributions, the Extremoscope project). Then, it briefly presents the development of five innovative services: the impact of climate change on coastal regions and the assessment of submersion risks, the evolution of aquifers with climate change, impacts for agriculture in western Africa, the evolution of sea ecosystems in the Mediterranean Sea and the definition of marine protected areas, and a climate service for cities. It briefly addresses associated needs in terms of basic and professional training, and in terms of communication with experts, undertakers, citizen, and so on.
[en] We examine long-term trends in the historical record of extreme precipitation events occurring over the French Mediterranean area. Extreme events are considered in terms of their intensity, frequency, extent and precipitated volume. Changes in intensity are analysed via an original statistical approach where the annual maximum rainfall amounts observed at each measurement station are aggregated into a univariate time-series according to their dependence. The mean intensity increase is significant and estimated at + 22% (+ 7 to + 39% at the 90% confidence level) over the 1961–2015 period. Given the observed warming over the considered area, this increase is consistent with a rate of about one to three times that implied by the Clausius–Clapeyron relationship. Changes in frequency and other spatial features are investigated through a Generalised Linear Model. Changes in frequency for events exceeding high thresholds (about 200 mm in 1 day) are found to be significant, typically near a doubling of the frequency, but with large uncertainties in this change ratio. The area affected by severe events and the water volume precipitated during those events also exhibit significant trends, with an increase by a factor of about 4 for a 200 mm threshold, again with large uncertainties. All diagnoses consistently point toward an intensification of the most extreme events over the last decades. We argue that it is difficult to explain the diagnosed trends without invoking the human influence on climate.
[en] Climate change has increased the days of un-seasonal temperature. Although many studies have examined the association between temperature and mortality, few have examined the timing of exposure where whether this association varies depending on the exposure month even at the same temperature. Therefore, we investigated monthly differences in the effects of temperature on mortality in a study comprising a wide range of weather and years, and we also investigated heterogeneity among regions. We analyzed 38,005,616 deaths from 148 cities in the U.S. from 1973 through 2006. We fit city specific Poisson regressions to examine the effect of temperature on mortality separately for each month of the year, using penalized splines. We used cluster analysis to group cities with similar weather patterns, and combined results across cities within clusters using meta-smoothing. There was substantial variation in the effects of the same temperature by month. Heat effects were larger in the spring and early summer and cold effects were larger in late fall. In addition, heat effects were larger in clusters where high temperatures were less common, and vice versa for cold effects. The effects of a given temperature on mortality vary spatially and temporally based on how unusual it is for that time and location. This suggests changes in variability of temperature may be more important for health as climate changes than changes of mean temperature. More emphasis should be placed on warnings targeted to early heat/cold temperature for the season or month rather than focusing only on the extremes. (authors)
[en] Ambitious climate change mitigation plans call for a significant increase in the use of renewables, which could, however, make the supply system more vulnerable to climate variability and changes. Here we evaluate climate change impacts on solar photovoltaic (PV) power in Europe using the recent EURO-CORDEX ensemble of high-resolution climate projections together with a PV power production model and assuming a well-developed European PV power fleet. Results indicate that the alteration of solar PV supply by the end of this century compared with the estimations made under current climate conditions should be in the range (-14%;+2%), with the largest decreases in Northern countries. Temporal stability of power generation does not appear as strongly affected in future climate scenarios either, even showing a slight positive trend in Southern countries. Therefore, despite small decreases in production expected in some parts of Europe, climate change is unlikely to threaten the European PV sector. (authors)
[en] A global warming of 2 °C relative to pre-industrial climate has been considered as a threshold which society should endeavor to remain below, in order to limit the dangerous effects of anthropogenic climate change. The possible changes in regional climate under this target level of global warming have so far not been investigated in detail. Using an ensemble of 15 regional climate simulations downscaling six transient global climate simulations, we identify the respective time periods corresponding to 2 °C global warming, describe the range of projected changes for the European climate for this level of global warming, and investigate the uncertainty across the multi-model ensemble. Robust changes in mean and extreme temperature, precipitation, winds and surface energy budgets are found based on the ensemble of simulations. The results indicate that most of Europe will experience higher warming than the global average. They also reveal strong distributional patterns across Europe, which will be important in subsequent impact assessments and adaptation responses in different countries and regions. For instance, a North–South (West–East) warming gradient is found for summer (winter) along with a general increase in heavy precipitation and summer extreme temperatures. Tying the ensemble analysis to time periods with a prescribed global temperature change rather than fixed time periods allows for the identification of more robust regional patterns of temperature changes due to removal of some of the uncertainty related to the global models’ climate sensitivity. (paper)
[en] The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate inter-annual variability and changes expected from greenhouse gas emissions. (authors)