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The aim of the study is to analyze and discuss possible climate change impacts on flood damages in Germany. The study was initiated and supported by the German insurance sector whereby the main goal was to identify general climate-related trends in flood hazard and damages and to explore sensitivity of results to climate scenario uncertainty. The study makes use of climate scenarios regionalized for the main river basins in Germany. A hydrological model (SWIM) that had been calibrated and validated for the main river gauges, was applied to transform these scenarios into discharge for more than 5000 river reaches. Extreme value distribution has been fitted to the time series of river discharge to derive the flood frequency statistics. The hydrological results for each river reach have been linked using the flood statistics to related damage functions provided by the German Insurance Association, considering damages on buildings and small enterprises. The result is that, under the specific scenario conditions, a considerable increase in flood related losses can be expected in Germany in future, warmer, climate.

The mean climatic development for Germany was investigated within the period 2031/60 in comparison to the situation in the observational period 1981/2010. The RCP8.5-Scenario of the IPCC was used because it reflects the actual CO2-emissions very well. On this basis the temperature trend for Germany was estimated using 21 GCM runs up to the year 2100. This temperature trend was the driving force for the statistical regional climate model STARS. 100 ensemble runs of the model STARS were compared with the scenario period and with the observational period. Temperature, precipitation, climatic water balance and some additional parameters were analyzed. One important result is the change in the distribution of precipitation in Germany during the year – decrease in summer, increase in winter. Finally the future climate development leads to a negative climatic water balance over the whole year.

We present projections of winter storm-induced insured losses in the German residential building sector for the 21st century. With this aim, two structurally most independent downscaling methods and one hybrid downscaling method are applied to a 3-member ensemble of ECHAM5/MPI-OM1 A1B scenario simulations. One method uses dynamical downscaling of intense winter storm events in the global model, and a transfer function to relate regional wind speeds to losses. The second method is based on a reshuffling of present day weather situations and sequences taking into account the change of their frequencies according to the linear temperature trends of the global runs. The third method uses statistical-dynamical downscaling, considering frequency changes of the occurrence of storm-prone weather patterns, and translation into loss by using empirical statistical distributions. The A1B scenario ensemble was downscaled by all three methods until 2070, and by the (statistical-) dynamical methods until 2100. Furthermore, all methods assume a constant statistical relationship between meteorology and insured losses and no developments other than climate change, such as in constructions or claims management. The study utilizes data provided by the German Insurance Association encompassing 24 years and with district-scale resolution. Compared to 1971–2000, the downscaling methods indicate an increase of 10-year return values (i.e. loss ratios per return period) of 6–35 % for 2011–2040, of 20–30 % for 2041–2070, and of 40–55 % for 2071–2100, respectively. Convolving various sources of uncertainty in one confidence statement (data-, loss model-, storm realization-, and Pareto fit-uncertainty), the return-level confidence interval for a return period of 15 years expands by more than a factor of two. Finally, we suggest how practitioners can deal with alternative scenarios or possible natural excursions of observed losses.

The development of winter storm- and summer thunderstorm-related loss events within the next decades in Germany was investigated with regard to change in frequency and intensity caused by climate changes. As a first step, observed meteorological data were connected with insurance data on a statistical basis. A regional climate model was then used to estimate future climate development. Using the statistical relations between meteorological and insurance data, the development of climate-driven damages was calculated. Results show that an increase of loss events can be expected within the next decades. These results show loss ratios shifting from higher return periods to smaller ones. In progressive decades, all these loss events become regionally more differentiated.

In this article, the authors examine the effect of a high-resolution grid (grid resolution lower than 3 km) in the context of a realistic climate simulation. For this purpose global simulation results of the German Weather Service were dynamically downscaled in a one-way nesting approach to 2.8 km using the regional forecast model of the Consortium for Small-Scale Modeling (COSMO) of the German Weather Service. The simulations were performed for the region of central Europe in 2003. In particular, the authors investigate whether COSMO adequately handles extreme events such as the persistent drought and heat of the summer of 2003. Comparisons of the simulated atmospheric conditions in terms of 2-m temperature, mean sea level pressure, and precipitation demonstrated a good correspondence to their associated observational data. Simulation results and observed data are both given as time series at locations such as grid cells or station locations. By cluster analysis a representation of the spatial structure for observation data and simulation results is found. The kappa statistic evaluates how well the two spatial structures correspond to each other. The different kappa variants are helpful to diagnose where shortcomings of the simulation results are located.

This study presents a newly compiled dataset of modern pollen and climate data from 798 sites across Japan and the Russian Far East. This comprehensive reference dataset combined with the modern analogue technique (MAT) provides a powerful tool for pollen-based reconstruction of the Quaternary Northwest Pacific climate. Pollen-derived reconstruction of the modern climate at the reference pollen-sampling sites matches well with the estimated modern climate values (R2 values vary between 0.79 and 0.95, and RMSEP values vary between 5.8 and 9.7% of the modern climatic range for all nine tested variables). The successful testing of the method encourages its application to the fossil pollen records. We used a coarse-resolution pollen record from Lake Biwa to reconstruct glacial–interglacial climate dynamics in central Japan since ~ 438 kyr and compared it to the earlier reconstruction based on a less representative reference dataset. The current and earlier results consistently demonstrate that the coldest glacial intervals experienced pronounced cooling in winter and moderate cooling in summer, supporting the growth of cool mixed forest (COMX) where warm mixed forest (WAMX) predominates today. During the last glacial, maximum (~ 24 kyr BP) mean temperatures of the coldest (MTCO) and warmest (MTWA) month were about − 13 °C (RMSEP = 2.34 °C) and 21 °C (RMSEP = 1.66 °C) respectively, and annual precipitation (PANN) was about 800 mm (RMSEP = 158.06 mm). During the thermal optimums of the interglacial intervals, the temperatures of the coldest and warmest month were above 0 °C and 25 °C respectively, leading to the reconstruction of WAMX and temperate conifer forest (TECO). Although both these vegetation types grow in the southern part of Japan today, WAMX requires warmer space. The presence of WAMX during marine isotope stages (MIS) 11 and 1, and its absence during MIS 9 and MIS 5 contradict the marine isotope and Antarctic ice records, suggesting that the latter two interglacials were the warmest of the last 800 kyr. The apparent contradiction allows at least three different explanations including low temporal resolution of the pollen record; different trends in CO2 concentrations during ‘short’ and ‘long’ interglacials; and regional climate variability and non-linear response of different regions to the global forcing. More definitive conclusions will be possible on the basis of forthcoming high-resolution pollen records from central Japan.

In most of Europe, an increase in average annual surface temperature of 0·8 °C is observed, and a further increase is projected. Precipitation tends to increase in northern Europe and decrease in southern Europe, with variable trends in central Europe. The climate scenarios for Germany suggest an increase in precipitation in western Germany and a decrease in eastern Germany, and a shift of precipitation from summer to winter. When investigating the effects of climate change, impacts on water resources are among the main concerns. In this study, the first German-wide impact assessment of water fluxes dynamics under climate change is presented in a spatially and temporally distributed manner using the state-of-the-art regional climate model, Statistical Regional (STAR) model and the semi-distributed process-based eco-hydrological model, soil and water integrated model (SWIM). All large river basins in Germany (lower Rhine, upper Danube, Elbe, Weser and Ems) are included. A special focus of the study was on data availability, homogeneity of data sets, related uncertainty propagation in the model results and scenario-related uncertainty. After the model calibration and validation (efficiency from 0·6 to 0·9 in 80% of cases) the water flow components were simulated at the hydrotope level, and the spatial distributions were compared with those in the Hydrological Atlas of Germany. The actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions. The results for the second scenario period 2051–2060 show that water discharge in all six rivers would be 8–30% lower in summer and autumn compared with the reference period, and the strongest decline is expected for the Saale, Danube and Neckar. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). However, the uncertainty of impacts, especially in winter and for high water flows, remains high. Copyright © 2010 John Wiley & Sons, Ltd.

Anomalies of mean air temperature of 12 consecutive months were detected recently at a number of spatial scales: from local via national and continental, to hemispheric. At all these spatial scales, pre-2007 records were exceeded by considerable margins. The recent rise in the mean temperature of 12 consecutive months at several scales has remained largely unnoticed, because the 12-month means are seldom analyzed. Broad attention is typically focused on monthly, seasonal and annual temperatures. Analysis of shifted 12-month periods helps spot peculiar 12-month episodes with remarkable temperature anomalies that do not coincide with a calendar year. Introducing 12-month running mean temperatures into the global warming debate can prove useful.

Annual precipitation for the last 2,500 years was reconstructed for northeastern Qinghai from living and archaeological juniper trees. A dominant feature of the precipitation of this area is a high degree of variability in mean rainfall at annual, decadal, and centennial scales, with many wet and dry periods that are corroborated by other paleoclimatic indicators. Reconstructed values of annual precipitation vary mostly from 100 to 300 mm and thus are no different from the modern instrumental record in Dulan. However, relatively dry years with below-average precipitation occurred more frequently in the past than in the present. Periods of relatively dry years occurred during 74–25 BC, AD 51–375, 426–500, 526–575, 626–700, 1100–1225, 1251–1325, 1451–1525, 1651–1750 and 1801–1825. Periods with a relatively wet climate occurred during AD 376–425, 576–625, 951–1050, 1351–1375, 1551–1600 and the present. This variability is probably related to latitudinal positions of winter frontal storms. Another key feature of precipitation in this area is an apparently direct relationship between interannual variability in rainfall with temperature, whereby increased warming in the future might lead to increased flooding and droughts. Such increased climatic variability might then impact human societies of the area, much as the climate has done for the past 2,500 years.

Climate should be regarded as a complex system, thus requiring an investigation of its complex changes. For this purpose, it is obvious to define climate types that are determined by a number of factors to be able to afterwards investigate the way they are changing. The most popular procedure so far consists in defining threshold values – as a rule for temperature and precipitation for the seasons – to determine those areas as a climate type that are within these threshold values. A popular example of this procedure is the frequently used Koppen climate classification (Koppen, 1931; Fraedrich et al., 2001). The drawback of this methodology consists in the fact that the threshold values can be absolutely plausible but need to be given subjectively in any case. The first question is: Can be a methodology developed here for the identification of climate changes in an objective way? First, all regions with a structural behavior as similar as possible are combined in one climate type and the pertaining threshold values of the meteorological parameters used are determined afterwards. Regions or areas with the same structure can be determined by means of a pattern recognition method. An extended non-hierarchic cluster analysis will be used for this purpose in the investigation. This cluster analysis provides a number of statistically separated patterns (climate types) for the climate classification on earth. So the characteristics of each climate type can be described. The second question that needs to be answered now can be formulated as follows: Are there any changes in the location and dimension of individual climate types due to the global climate changes presently observed? In order to answer this question, the shifting of the climate types during the observed period must be calculated. After calculation, an analysis of the results follows, first for the global scale as a whole and second more detailed for each continent and selected regions. So the chapter gives an overview on the actual climate changes for different scales. Section 2 describes the basis of the data and its validation. The methodology can be found in section 3 followed by the analysis of the actual climate changes for the whole earth and each continent in section 4. Finally some conclusions are made in section 5.

We analyze century-long daily temperature and precipitation records for stations in Europe west of 60 degrees E. A set of climatic indices derived from the daily series, mainly focusing on extremes, is defined. Linear trends in these indices are assessed over the period 1901-2000. Average trends, for 75 stations mostly representing Europe west of 20 degrees E, show a warming for all temperature indices. Winter has, on average, warmed more (similar to 1.0 degrees C/100 yr) than summer (similar to 0.8 degrees C), both for daily maximum (TX) and minimum (TN) temperatures. Overall, the warming of TX in winter was stronger in the warm tail than in the cold tail (1.6 and 1.5 degrees C for 98th and 95th, but similar to 1.0 degrees C for 2nd, 5th and 10th percentiles). There are, however, large regional differences in temperature trend patterns. For summer, there is a tendency for stronger warming, both for TX and TN, in the warm than in the cold tail only in parts of central Europe. Winter precipitation totals, averaged over 121 European stations north of 40 degrees N, have increased significantly by similar to 12% per 100 years. Trends in 90th, 95th and 98th percentiles of daily winter precipitation have been similar. No overall long-term trend occurred in summer precipitation totals, but there is an overall weak (statistically insignificant and regionally dependent) tendency for summer precipitation to have become slightly more intense but less common. Data inhomogeneities and relative sparseness of station density in many parts of Europe preclude more robust conclusions. It is of importance that new methods are developed for homogenizing daily data.

This research topic has two main goals. The first is to supply spatially and temporally consistent data for a drought period in the northeast of Brazil, generated by a dynamic mode1ing approach. The second is to elaborate a state-of-the-art regional-scale climate model, which can be applied to simulate scenarios of future climatic developments in the northeast of Brazil. For this, two different types of such models were adapted to the region of interest and were investigated for their ability to reproduce present-day extreme weather conditions. To assess a model’s performance here in terms of the specific drought conditions in the WAVES project area under agricultural aspects, a new validation algorithm has been developed and applied. With this method, errors can be quantified on a statistical basis and can then be accumulated to form general quality measures. Possible sources of inaccuracies were identified as being linked to the representation of hydrological soil processes. On the basis of these results, sensitivity experiments were designed and carried out to investigate the effect of implementing various modified descriptions of the soil hydrology on the accuracy of the model simulations. Finally, a regional climate model version was elaborated which is able to reproduce present-day climatic conditions within a range of errors as characteristic for coarser-scale dynamic modeling approaches, but with a better representation of smaller scales. Remarkable improvements were achieved regarding the representation of drought conditions by the dynamic climate model. It is, however, still a challenging task for the future to further reduce the range of errors for regional-scale features in the simulation results to such an order of magnitude as is known from gridded observations. To reach this objective, further investigations on soil—water and energy balances and near-surface vertical exchange processes are required.