But anthropogenic change of Earth’s climate is altering the means and extremes of these factors so that this paradigm of stationarity no longer applies, researchers report in the latest issue of “Science”. The headline of the article by Christopher Milly, US Geological Survey (USGS), and others reads “Stationarity is dead: Whither Water Management?”.
Model-projected percentage change (2041-2060 vs. 1900-1970) in mean annual runoff volume for ice-free land, under the Intergovernmental Panel on Climate Change “SRES A1B” scenario. Copyright: Science
Water professionals around the world have always had to balance water supply and demand and to minimize risks to life and property without knowing what future events nature has in store. Historically, looking back at past observations has been a good way to estimate future conditions. “But climate change magnifies the possibility that the future will bring droughts or floods never seen in old measurements,” says Christopher Milly.
“When planning grand investments in water infrastructure area, one has to consider the uncertain and changing climate,” says Zbigniew Kundzewicz, leader of the hydrology group at the Potsdam Institute for Climate Impact Research and co-author of the Science article. Annual global investment in water infrastructure, e.g. canalization, dams or power stations, exceeds 500 billion US dollars. When planning new infrastructure and renewing decaying one non-stationarity has to be taken into account. “Large projected changes in runoff push hydroclimate beyond the range of historical behavior,” says Kundzewicz.
As the authors point out in their article, warming augments atmospheric humidity and water transport. This increases precipitation, and possibly flood risk, where prevailing atmospheric water-vapor fluxes converge. Glacial meltwater temporarily enhances water availability, but glacier and snow-pack losses diminish natural storage of freshwater. In coastal regions the supplies are endangered by rising sea levels. The risk of contamination with seawater is heightened, the authors state.
From projections of future water availability a picture emerges of regional gainers and losers. The paper by Milly et al. contains a global map illustrating the projected changes at the level of countries, and partly states or provinces. Climate models show where the runoff changes are projected to be largest. The global pattern of already visible annual streamflow trends is unlikely to have arisen by chance and is consistent with modeled response to climate forcing. Water availability will probably increase substantially in high latitudes of the northern Hemisphere and some tropical regions and decrease substantially in the Mediterranean basin, southern Africa and south-western North America. “These drying regions are likely to experience increasing drought frequency in the future,” says Milly.
“Stationarity cannot be revived,” says Kundzewicz. Even with aggressive mitigation of climate change, continued warming is very likely, given the residence time of atmospheric carbon dioxide and the thermal inertia of the earth system. However, the rational water resources planning framework can be adapted to the changing climate. The information base changes rapidly with climate science advances. A rapid exchange of climate-change information between the scientific realm and water managers will be critical, the authors state. New, higher-resolution models could then represent surface- and ground-water processes more explicitly. These models need to include water infrastructure, and water users, including the agricultural and energy sectors. Modeling should be used to synthesize observations, but it can never replace them, the authors write and suggest to update the analytical strategies used for planning under conditions of non-stationarity. “The assumption that the past is the key to the future has lost much of its value for water management,” says Kundzewicz.
Zbigniew Kundzewicz is Professor of Earth Sciences at the Polish Academy of Sciences’ RCAFE Centre in Poznan. He is leader of the hydrology group in the research domain “Climate Impacts & Vulnerabilities” at the Potsdam Institute for Climate Impact Research. Kundzewicz was recently awarded the Grand Seal of the City of Poznan for his scientific work.
Uta Pohlmann | alfa
GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center
Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy