Dynamical downscaling of CMIP5 1 Global Circulation Models over CORDEX-Africa with COSMO-CLM: evaluation over the present climate and analysis of the added value.

In this work we present the results of the application 8 of the Consor- tium for Small-scale Modeling (COSMO) Regional Climate Model (COSMO-CLM, hereafter, CCLM) over Africa in the context of the Coordinated Regional Climate Downscaling Experiment (CORDEX). An ensemble of climate change projections has been created by downscaling the simulations of four Global ClimateModels (GCM), namely:MPI-ESM-LR, HadGEM2- ES, CNRM-CM5, and EC-Earth. Here we compare the results of CCLM to those of the driving GCMs over the present climate, in order to investigate whether RCMs are effectively able to add value, at regional scale, to the performances of GCMs. It is found that, in general, the geographical distribution of mean sea level pressure, surface temperature and seasonal precipitation is strongly affected by the boundary conditions (i.e. driving GCMs), and seasonal statistics are not always improved by the downscaling. However, CCLM is generally able to better represent the annual cycle of precipitation, in particular over Southern Africa and the West Africa Monsoon (WAM) area. By performing a Singular Spectrum Analysis (SSA) it is found that CCLM is able to reproduce satisfactorily the annual and sub-annual principal components of the precipitation time series over the Guinea Gulf, whereas the GCMs are in general not able to simulate the bimodal distribution due to the passage of the WAM and show a unimodal precipitation annual cycle. Furthermore, it is shown that CCLM is able to better reproduce the Probability Distribution Function (PDF) of precipitation and some impact-relevant indices such as the number of consecutive wet and dry days, and the frequency of heavy rain events.JRC.H.7-Climate Risk Managemen

Frequency analysis of critical meteorological conditions in a changing climate - Assessing future implications for railway transportation in Austria

Meteorological extreme events have great potential for damaging railway infrastructure and posing risk to the safety of train passengers. In the future, climate change will presumably have serious implications on meteorological hazards in the Alpine region. Hence, attaining insights on future frequencies of meteorological extremes with relevance for the railway operation in Austria is required in the context of a comprehensive and sustainable natural hazard management of the railway operator. In this study, possible impacts of climate change on the frequencies of so-called critical meteorological conditions (CMCs) between the periods 1961-1990 and 2011-2040 are analysed. Thresholds for such CMCs have been defined by the railway operator and used in its weather monitoring and early warning system. First, the seasonal climate change signals for air temperature and precipitation in Austria are described on the basis of an ensemble of high-resolution Regional Climate Model (RCM) simulations for Europe. Subsequently, the RCM-ensemble was used to investigate changes in the frequency of CMCs. Finally, the sensitivity of results is analysed with varying threshold values for the CMCs. Results give robust indications for an all-season air temperature rise, but show no clear tendency in average precipitation. The frequency analyses reveal an increase in intense rainfall events and heat waves, whereas heavy snowfall and cold days are likely to decrease. Furthermore, results indicate that frequencies of CMCs are rather sensitive to changes of thresholds. It thus emphasizes the importance to carefully define, validate and – if needed – to adapt the thresholds that are used in the weather monitoring and warning system of the railway operator. For this, continuous and standardized documentation of damaging events and near-misses is a pre-requisite.JRC.H.7-Climate Risk Managemen

Mean and extreme climate in Europe under 1.5, 2, and 3°C global warming

Based on high-resolution regional climate models, the change over Europe in mean climate and extremes, including impact-relevant indicators, are investigated under different levels of global warming (1.5°C, 2°C, and 3°C). A suit of indices describing both hot and cold events are employed and, for precipitation, wet and dry conditions; in particular, we examine the evolution of threshold-based indices, such as the number of frost days or tropical nights, which may be relevant for impact assessment on specific sectors.JRC.E.1-Disaster Risk Managemen

Forest Fires and Adaptation Options in Europe

This paper presents a quantitative assessment of adaptation options in the context of forest fires in Europe under projected climate change. A standalone fire model (SFM) based on a state-of-the-art large-scale forest fire modelling algorithm is used to explore fuel removal through prescribed burnings and improved fire suppression as adaptation options. The climate change projections are provided by three climate models reflecting the SRES A2 scenario. The SFM’s modelled burned areas for selected test countries in Europe show satisfying agreement with observed data coming from two different sources (European Forest Fire Information System and Global Fire Emissions Database). Our estimation of the potential increase in burned areas in Europe under ‘‘no adaptation’’ scenario is about 200 % by 2090 (compared with 2000–2008). The application of prescribed burnings has the potential to keep that increase below 50 %. Improvements in fire suppression might reduce this impact even further, e.g. boosting the probability of putting out a fire within a day by 10 % would result in about a 30 % decrease in annual burned areas. By taking more adaptation options into consideration, such as using agricultural fields as fire breaks, behavioural changes, and long-term options, burned areas can be potentially reduced further than projected in our analysis.JRC.H.7-Climate Risk Managemen

Quantifying the effect of Tmax extreme events on local adaptation to climate change of maize crop in Andalusia for the 21st century

Extreme events of Tmax can threaten maize production on Andalusia (Ruiz-Ramos et al., 2011). The objective of this work is to attempt a quantification of the effects of Tmax extreme events on the previously identified (Gabaldón et al., 2013) local adaptation strategies to climate change of irrigated maize crop in Andalusia for the first half of the 21st century

PESETA III – Task1: Climate change projections, bias-adjustment, and selection of model runs

Global warming will greatly affect the climate at regional and local scale through, e.g., the increase of intensity and frequency of extreme weather events (floods, droughts, heat waves, etc.). In order to assess the impact of climate change at such scale (on, e.g., the hydrological cycle or crop production) it is necessary to attain meteorological information with a spatial detail much finer than that provided by global climate models (GCMs). High-resolution climate projections are usually obtained by employing regional climate models (RCMs), which are able to better resolve small-scale features such as topography and heterogeneous land use. When compared to present-day observations, however, the results of climate models can present large biases; in order to be used as an input for process-based impact models (like in PESETA III) outputs from RCMs are usually further post-processed by means of statistical techniques known as bias-correction (or bias-adjustment). Here, we describe the projections of climate change used in PESETA III and the bias-adjustment method applied to them, focusing on the analysis of a series of climate change indices for both the mean climate and extreme events (such as the number of frost days, of the number of consecutive dry days) relevant for impact assessment studies. Results show that, under the RCP8.5 emission scenario, at the end of the Century, maximum temperature is expected to increase, in winter, between about 2.5∘C over the British Isles and 4.8∘C over Scandinavia. In summer, the projected change ranges between 2.5∘C over Britain and 4.7∘C over the Iberian Peninsula. Winter precipitation is projected to increase over most of central and northern Europe in both frequency, and intensity, with a consequent increase of the number of consecutive wet days, and reduction of consecutive dry days. The change in precipitation frequencies distribution is not uniform, though, and a reduction in low precipitation intensity is accompanied by an increase of extreme events, even for the Mediterranean regions where total precipitation is projected to decrease. In summer, a general reduction in precipitation is projected for all regions except Scandinavia and Eastern Europe; as for winter, there is a tendency toward less frequent but more severe precipitation episodes. A set of 12 RCMs’ bias-adjusted climate change projections is provided to the PESETA III impact modellers; the use of such a large ensemble of runs is essential to quantify the uncertainty in climate projections (the so-called inter-model variability). In fact, each model’s run (driven by the same emission scenario) represents an equally plausible projection of the future evolution of the climate. However, due to differences in the models’ formulation and physical parameterization, the climate change signal projected by different models may present significant differences. Due to resource limitations, some impact model groups may not be able to use all the 12 provided runs; in this case, a sub-set of 5 runs is selected to be used by all impact models (compulsory core runs). The sub-set of core runs needs to be able to reproduce, as accurately as possible, the inter-model variability of the entire ensemble. The selection of the sub-set has been performed by means of Principal Component Analysis (PCA) on the bias adjusted climate change indices. Finally, the PESETA III protocol also requires investigating the impacts of a 2ᵒC global warming, compared to the preindustrial period. Here for each RCM run, the timing of reaching 2ᵒC warming is provided following the same procedure used in the FP7 project IMPACT2C, namely: - It is assumed that the climate in a +2ᵒC world is comparable irrespective of when and how fast this warming is reached - An RCM is defined to project a 2ᵒC global warming when the corresponding driving GCM reaches the 2ᵒC threshold, under RCP8.5 emission scenario - For each GCM-RCM run, the +2ᵒC period is defined as the 30 year period centred around the year when the 2ᵒC global warming is first reachedJRC.E.1-Disaster Risk Managemen

Modelling water demand and availability scenarios for current and future land use and climate in the Sava River Basin

170 Simulations with the LISFLOOD water resources for 30-year periods with various combinations of land use change and climate change have been evaluated for their impact on the water-food-energy-environment nexus in the Sava river basin. For the Sava river basin, we found in this study that more intense irrigated agriculture does have the potential to increase crop yields considerably, but there are not sufficient water resources available to realise this. Also, if irrigation would be increased drastically, other sectors would be negatively influenced, such as the energy sector (reduced cooling water availability, potentially less water at times produce hydropower), navigation (more frequent and lower low-flows), and the environment (breaches of environmental or minimum flow conditions). Effects on water resources would be more significant with increased irrigation to increase the crop yield of e.g maize. This would lead to an increase in water demand from 2216 Mm3/year to 3337 Mm3/year. Overall water demand in the Sava basin would further increase to around 6000 Mm3/year if we combine both increased irrigation and climate projections until 2100. The average simulated maize yield could increase from 5.7 tons/ha at present conditions to 9.9 tons/ha in case of increased and optimum irrigation. These substantial increases in irrigation, which would lead to substantial crop yield increases as well, would lead to water scarcity in parts of the Sava basin. Also, there just is not sufficient water to irrigate all areas which are water-limited for crop growth. Existing irrigation plans and irrigating the areas which were previously equipped for irrigation (according to FAO) seems more feasible from a water resources perspective. Flood peaks are projected to remain unchanged as a consequence of projected land use changes until 2050 for the Sava basin. However, with climate change projections we do simulate an overall increase in the flood peaks with 13% for the 2011-2040 period and a 23% increase for the 2071-2100 period. River low-flows decrease moderately for the 2011-2040 scenarios. For the end of the century 2071-2100, lowflow values are projected to moderately increase as compared to the control 1981-2010 climate. Excessive irrigation would result in a severe decrease of the lowflow discharges with 50-60%. As for ecological flows, similar observations can be made. Navigation in the main Sava river may be affected by these trends. Water availability for energy production - hydropower and cooling water for thermal and nuclear power stations – is projected to decrease by an average of 3.3% for 2030 under RCP4.5, whereas RCP8.5 would result in a 1.3% increase. End of the century simulations yield a 17.6% higher Q50 for RCP4.5 and 23.1% higher for RCP8.5. Excessive irrigation could affect the water availability for power production, especially for cooling thermal power stations. Hydropower reservoirs could be turned into multi-functional reservoirs, also serving downstream irrigation needs and flood control, and thus serve multiple purposes.JRC.D.2-Water and Marine Resource

Projections of indices of daily temperature and precipitation based on bias-adjusted CORDEX-Africa regional climate model simulations

AbstractWe present a dataset of daily, bias-adjusted temperature and precipitation projections for continental Africa based on a large ensemble of regional climate model simulations, which can be useful for climate change impact studies in several sectors. We provide guidance on the benefits and caveats of using the dataset by investigating the effect of bias-adjustment on impact-relevant indices (both their future absolute value and change). Extreme threshold-based temperature indices show large differences between original and bias-adjusted values at the end of the century due to the general underestimation of temperature in the present climate. These results indicate that when biases are accounted for, projected risks of extreme temperature-related hazards are higher than previously found, with possible consequences for the planning of adaptation measures. Bias-adjusted results for precipitation indices are usually consistent with the original results, with the median change preserved for most regions and indices. The interquartile and full range of the original model ensemble is usually well preserved by bias-adjustment, with the exception of maximum daily precipitation, whose range is usually greatly reduced by the bias-adjustment. This is due to the poor simulation and extremely large model range for this index over the reference period; when the bias is reduced, most models converge in projecting a similar change. Finally, we provide a methodology to select a small subset of simulations that preserves the overall uncertainty in the future projections of the large model ensemble. This result can be useful in practical applications when process-based impact models are too expensive to be run with the full ensemble of model simulations

Summary of the Meeting on 11 December 2015 on Adaptation of Structural Design to Climate Change

The objectives of the meeting were as follows: 1. Discuss the feasibility and needs for creating snow map for structural design which accounts for the climate change: • availability of methodology and data; • scope of a snow map project – geographic, time span; • support / resources needed. 2. Set-up a group to create a document on the rational and needs for a snow map for structural design which accounts for the climate change. 3. Discuss the interaction with CEN/TC 250 Project Team (PT) on SC1.T5 (the Project Team on the CEN report on adaptation of the Eurocodes to the climate change, Task 5 of SC1, under Mandate M/515). 4. Identify other actions on structures whose effect on structures shall be consideredJRC.G.4-European laboratory for structural assessmen

The snow load in Europe and the climate change

It is often assumed that, as a consequence of global warming, a reduction of snow load on the ground should be expected. In reality, snow load is often depending on local orographic situations that can determine an increase of its height, even when the average snow height over the surrounding areas is reduced. Large snow loads on roofs during the winter season of 2005–2006 led to over 200 roof collapses in Central Europe. To proceed with the adaptation of the European standards for important buildings and infrastructures to the implications of climate change, the expected changes in the climatic loading shall be assessed in terms of the Eurocodes concept for characteristic values of variable climatic actions. The paper presents a procedure for derivation of snow load on ground from data on daily temperatures and precipitation. In addition, it allows to derive the characteristic snow loads from climate change projections and thus to evaluate the future trends in variation of snow loading. Analysis of these trends for the Italian territory is performed by comparing the results for several subsequent time periods of thirty years, with those obtained for the reference period 1951–1980. Results presented show a significant increase in the snow loading for the period 1981–2010 in many regions in north and east Italy in comparison with the reference period. It is suggested that a European project on snow load map shall be started, in order to help National Competent Authorities to redraft the national snow load maps for design with the Eurocodes