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The European Commission Flood Risk Directive review shows that while many nations have embraced the concepts of flood risk management, there is still quite more to do in delineating risk–cost-effective measures and developing cost estimates and financing of those measures. Not mentioned are the necessary changes to existing design standards and protocols which will have to change in order to properly encompass climate change and variability, with associated uncertainties. Adjustments in engineering design standards and changes in hazards are examined, based on trend detection in observational records and projections for the future. Issues of urban and transport (motorways and railways) drainage design are also examined. Furthermore, risk reduction strategies are discussed. Finally, a way of accounting for non-stationarity in determining design precipitation and design floods is tackled. Climate change adjustments in engineering design standards, such as design precipitation and design floods, are reviewed via examples from Europe. [ABSTRACT FROM AUTHOR]

This study presents the analysis of bias-corrected projections of changes in temperature and precipitation in the Vistula and Odra basins, covering approximately 90?% of the Polish territory and small parts of neighbouring countries in Central and Eastern Europe. The ensemble of climate projections consists of nine regional climate model simulations from the EURO-CORDEX ensemble for two future periods 2021–2050 and 2071–2100, assuming two representative concentration pathways (RCPs) 4.5 and 8.5. The robustness is measured by the ensemble models' agreement on significant changes. We found a robust increase in the annual mean of daily minimum and maximum temperature, by 1–1.4?°C in the near future and by 1.9–3.8?°C in the far future (areal-means of the ensemble mean values). Higher increases are consistently associated with minimum temperature and the gradient of change goes from SW to NE regions. Seasonal projections of both temperature variables reflect lower robustness and suggest a higher future increase in winter temperatures than in other seasons, notably in the far future under RCP 8.5 (by more than 1?°C). However, changes in annual means of precipitation are uncertain and not robust in any of the analysed cases, even though the climate models agree well on the increase. This increase is intensified with rising global temperatures and varies from 5.5?% in the near future under RCP 4.5 to 15.2?% in the far future under RCP 8.5. Spatial variability is substantial, although quite variable between individual climate model simulations. Although seasonal means of precipitation are projected to considerably increase in all four combinations of RCPs and projection horizons for winter and spring, the high model spread reduces considerably the robustness, especially for the far future. In contrast, the ensemble members agree well that overall, the summer and autumn (with exception of the far future under RCP 8.5) precipitation will not undergo statistically significant changes.

The damage (in real terms after adjusting for inflation) caused by extreme weather events globally has increased dramatically over the past few decades. This is a result of an increase in the amplitude and frequency of weather extremes, as well as of human factors causing a widespread increase in levels of exposure and vulnerability. There are a number of reasons to consider that, in many regions of the globe, weather extremes (e.g. heat waves, droughts, forest fires, intense rainfall, floods and landslides) are becoming both yet more extreme and more frequent. Projections for the future based on climate and impact models point to a further strengthening of this trend. There has already been an increase in rainfall intensity in conditions of a warmer climate, and a continuation of this trend is expected, with adverse consequences for flood risk. However, the development of flood-prone areas and increase in damage potential are often the dominant factors underpinning growing flood damage and flood risk. In warmer climates, an increased risk of river and flash flooding caused by heavy rainfall, as well as an increasing risk of coastal flooding associated with sea level rise can be expected over large areas. By the same token, a reduction in the risk of snowmelt flooding events is projected in the warmer climate. Projections also indicate an increased risk of drought in many areas. The projections for climate change in Poland point to several risks associated with an increase in the frequency, intensity and severity of weather extremes (heat waves, intensive rainfall, flooding and landslides, coastal surges, drought during the growing season and winter, strong winds and pathogens associated with warming). Heat waves will become more frequent, more intense and more troublesome for the ageing population of Poland.

A review of findings contained in the IPCC AR5 Synthesis Report, of particular relevance to the Polish audience, is offered. Polish perspectives on coal-climate nexus are discussed in a broader, universal, context. Positive examples of climate policies in other countries are provided. The title of this paper refers to a public conference organized in Warsaw by the Embassies of France, Germany, and the UK and the Polish Academy of Sciences.

The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) is now available. It provides policymakers with an assessment of information on climate change, its impacts and possible response options (adaptation and mitigation). Summaries for policymakers of three reports of IPCC working groups and of the Synthesis Report have now been approved by IPCC plenaries. This present paper reports on the most essential findings in AR5. It briefly informs on the contents of reports of all IPCC working groups. It discusses the physical science findings, therein observed changes (ubiquitous warming, shrinking cryosphere, sea level rise, changes in precipitation and extremes, and biogeochemical cycles). It deals with the drivers of climate change, progress in climate system understanding (evaluation of climate models, quantification of climate system responses), and projections for the future. It reviews impacts, adaptation and vulnerability, including observed changes, key risks, key reasons for concern, sectors and systems, and managing risks and building resilience. Finally, mitigation of climate change is discussed, including greenhouse gas emissions in the past, present and future, and mitigation in sectors. It is hoped that the present article will encourage the readership of this journal to dive into the AR5 report that provides a wealth of useful information.

Flooding is the most destructive natural hazard in the Baltic Sea Basin in general and in Poland in particular. The notion includes floods from rivers and mountain torrents, as well as floods from sea surges in coastal areas, and floods from sewage systems. There have been several large floods in Poland in the last century and in recent decades, with damage exceeding 1% of the Polish GDP. The spatial and temporal characteristics of the flood risk in Poland are reviewed and observations and projections of changes in the flood hazard in the country are discussed. Furthermore, flood defences and flood preparedness systems in Poland are examined, with particular reference to the European Union (EU) Floods Directive, which is being implemented in Poland, an EU country. Finally, the public debate on flood risk and flood preparedness is reviewed.

Poland is a country where a climate change warming signal can be detected in temperature, but observed changes in other variables, and especially in precipitation, are complex. Temperature projections indicate further warming, but models do not agree as to seasonal distribution of changes in precipitation. This article reviews evidence for climate change and its impacts in Poland, in the context of observations and projections. It also reviews various aspects of climate change mitigation policy in the country whose energy supply is more coal‐dominated than any other country. This is one reason why climate change mitigation efforts are modest and climate policy largely passive. The dramatic decline of industrial production involving a rapid decline in CO2emissions during 1989–1992 was the crucial element of the Poland's position in the negotiations of international agreements. The European Union (EU) accession in 2004 tied Poland to EU climate policy. This cautious approach is largely in harmony with public attitudes. Poles are aware of climate change, but it is not considered as a priority issue and public opinion is divided about the issues of mitigation. Adaptation to climate change impacts in Poland is driven by the fact that observed impacts are not very large and there is no persuasive attribution of these impacts to greenhouse gas emissions. Reactive adaptation to climate change is preferred over anticipatory adaptation. There are several ‘special care’ areas in Poland in terms of adaptation: the mountains; the coastal zone of the Baltic Sea; and the river valleys. WIREs Clim Change2012 doi: 10.1002/wcc.175

Abstract In Central Europe, river flooding has been recently recognized as a major hazard, in particular after the 1997 Odra /Oder flood, the 2001 Vistula flood, and the most destructive 2002 deluge on the Labe/Elbe. Major recent floods in central Europe are put in perspective and their common elements are identified. Having observed that flood risk and vulnerability are likely to have grown in many areas, one is curious to understand the reasons for growth. These can be sought in socio-economic domain (humans encroaching into floodplain areas), terrestrial systems (land-cover changes – urbanization, deforestation, reduction of wetlands, river regulation), and climate system. The atmospheric capacity to absorb moisture, its potential water content, and thus potential for intense precipitation, are likely to increase in a warmer climate. The changes in intense precipitation and high flows are examined, based on observations and projections. Study of projected changes in intense precipitation, using climate models, for several areas of central Europe, and in particular, for drainage basins of the upper Labe/Elbe, Odra/Oder, and Vistula is reported. Significant changes have been identified between future projections and the reference period, of relevance to flood hazard in areas, which have experienced severe recent floodings.

AbstractAbstractOne of the important practical problems in the analysis of long time series of hydrological records is the evaluation of detectability of trends. This is not a trivial task, especially where the change is weak, while the natural variability is considerable (e.g. in the case of river flow records). The results of a study of a run-up effect allow experts to assess how strong a change (gradual trend or abrupt jump) must be and how long it must take in order to be detected by statistical tests. A set of generated, trend-free data mimicking river flow records, has been contaminated by the controlled addition of a gradual change or an abrupt jump. Analysis of detectability of change for different conditions of natural variability of the river flow process and for different properties of the contaminating component (its amplitude, intensity and run-up time) has been made, and the performance of different tests has been compared. The results are of broad applicability in the search for a climate change signature in hydrological data. Tests are not able to detect weak changes or changes which have not lasted long, but this cannot be interpreted as a demonstration of absence of a change. With the enhanced climate change, the changes of hydrological processes may be stronger and last longer, so that the likelihood of change detection may grow.

AbstractAbstractGeneral guidance is offered as to the methodology of change detection in time series of hydrological data, embracing stages such as preparing a suitable data set, exploratory analysis, application of adequate statistical tests and interpretation of results. Although the paper cannot go into full details of the many existing tests, it gives an easy-to-follow overview, offering practical hints and describing caveats and misconceptions. It serves as a refresher, raising attention to essential things that have often been ignored. A particular recommendation of the paper is that greater use of distribution-free testing methods, particularly resampling methods, should be made. These methods are recommended because they are particularly suited to hydrological data, which are often strongly skewed (non-normal), seasonal and serially correlated. Resampling techniques are flexible, robust and powerful, and require only minimal assumptions to be made about the data.

AbstractThe full text of this Editorial is at http://www.cig.ensmp.fr/~iahs/hsj/491/49191.htm

AbstractIn the last decade, there have been many destructive floods in various parts of the world. Despite the extensive investment in flood control works, neither flood occurrences nor damages are decreasing. A possible consequence of climate change is an increased frequency of extreme meteorological events that may cause floods. Discussion is offered of some recent large floods in the world and of the experiences in combating floods in Japan. Floods change over time as societies change. There is no single universal remedy against floods and site-specific local efforts are necessary. It is essential to undertake damage mitigation measures together with physical control measures for flood management in an integrated approach, using a mixture of structural and non-structural means. A more disaster conscious society needs to be built with better preparedness and safe-fail (safe in failure) rather than, unrealistic, fail-safe (safe from failure) design of flood defences.

AbstractThe flood that occurred in summer 1997 in Poland, affecting the drainage basins of the Odra and the Vistula, caused 54 fatalities and material losses of the order of billions of US$. The flood struck a large part of the country and caused inundation of 665 000 ha of land. The number of evacuees was 162 thousand. The rhetoric commonly used in Poland refers to the Great Flood of 1997 as an event whose scale exceeded all imagination about the possible size of the disaster. Indeed, historic maxima of river stage and flow rate were considerably exceeded. From the hydrological point of view, this flood was a very rare event, with a return period in some river cross-sections of the order of a thousand years and more. As this natural disaster, striking a dynamically developing country-in-transition, attracted much international interest, a holistic view of it is presented. Attempts to answer the questions: “Could the disaster have been avoided?” and “What lessons can be learnt from the flood?” are also made.

AbstractA river flow regime describes an average seasonal behaviour of river flow, usually representing a set of long-term monthly mean values. Seasonal patterns of flow can be regular, repeating in principle the same pattern from year to year, or irregular, i.e. alternating between a couple of different regime types during individual years. By tradition, a river flow regime has been considered as a static characteristic that does not change in large temporal scale, yet this may be an oversimplification with regard to constantly changing environmental conditions. Such a “static” description of a flow regime, based on long-term mean values is in discrepancy with the dynamic character of the system described. The dimension of this system in terms of fractal and intrinsic dimensions has been investigated on an example of Scandinavian runoff series by different methods: from a simple graphic method to determine the fractal dimension to empirical orthogonal function (EOF) and entropy-based aggregation to outline the number of patterns necessary for representing the regimes of different intrinsic dimension of a set of point data. The series studied demonstrated a variety of fractal and intrinsic dimensions that were well in agreement with the stability character of the investigated regime types. The less stable the regime, the higher were its fractal and intrinsic dimensions and the number of variables required for its description.

AbstractThere has been much recent emphasis on sustainable development of water resources in that the needs of the present generation are fulfilled without compromising future generations to meet their needs. Also, systems of flood protection and management are being increasingly considered in the context of sustainable development. Destructive floods have jeopardized settlements located near rivers since the dawn of human history. Now, the global flood losses have grown worldwide to the level of billions of US dollars per year. The issue of climate variability and change and the possibility of their adverse impacts on the severity and frequency of flooding, introduces an additional uncertainty to difficult sustainability issues. There are several examples of technical infrastructure related to flood protection, which are being criticized in the context of sustainable development because they close options for future generations and introduce unacceptable disturbances in ecosystems. Large structural flood defences like dams, storage reservoirs and embankments are often listed in this category. The means of coping with floods are looked at in the sustainability context. A change of paradigm is needed, as a flood protection system guaranteeing complete safety is an illusion. It is necessary to be aware of the possibility of floods, that is the attitude: “living with floods” seems more sustainable than a hopeless striving to “combat floods”.

The system concepts of importance to hydrological sciences are reviewed. The epochs of the development of systems sciences are discussed and their links with hydrological and water resources research are illustrated. Potentials and limitations of the system approach are discussed and the perspectives of further applications are sketched.

AbstractResults of a study on change detection in hydrological time series of annual maximum river flow are presented. Out of more than a thousand long time series made available by the Global Runoff Data Centre (GRDC) in Koblenz, Germany, a worldwide data set consisting of 195 long series of daily mean flow records was selected, based on such criteria as length of series, currency, lack of gaps and missing values, adequate geographical distribution, and priority to smaller catchments. The analysis of annual maximum flows does not support the hypothesis of ubiquitous growth of high flows. Although 27 cases of strong, statistically significant increase were identified by the Mann-Kendall test, there are 31 decreases as well, and most (137) time series do not show any significant changes (at the 10% level). Caution is advised in interpreting these results as flooding is a complex phenomenon, caused by a number of factors that can be associated with local, regional, and hemispheric climatic processes. Moreover, river flow has strong natural variability and exhibits long-term persistence which can confound the results of trend and significance tests.

View article at http://www.cig.ensmp.fr

AbstractThe full text of this Editorial is at http://www.cig.ensmp.fr/~iahs/hsj/496/49600.htm