The global dimension of water governance: Nine reasons for global arrangements in order to cope with local water problems

Where water problems extend beyond the borders of local communities, the catchment area or river basin is generally seen as the most appropriate unit for analysis, planning and institutional arrangements. In this paper it\ud is argued that addressing water problems at the river basin level is not always sufficient. It is shown that a substantial part of today’s water issues carries a (sub)continental or even global dimension, which urges for a governance approach that comprises coordination and institutional arrangements at a level above that of the river basin. This paper distinguishes and reviews nine developments that support this argument: • Local issues of water scarcity and flooding will be enhanced or weakened by human-induced global climate\ud change.\ud • Local problems of water pollution are often intrinsic to the structure of the global economy.\ud • There is a growing presence of multinationals in the drinking water sector.\ud • Several national governments are developing plans for large-scale inter-basin water transfers.\ud • An increasing number of water-short countries seek to preserve their domestic water resources through the\ud import of water in virtual form.\ud • Global trade in water-intensive commodities offers the opportunity of global water saving if this trade is\ud from countries with high to countries with low water productivity.\ud • The water footprints of individual people are increasingly externalised to other parts of the world, so that\ud many local water problems are strongly related to consumption elsewhere.\ud • Some people around the world have comparatively high water footprints, which raises the question of\ud whether this is fair and sustainable.\ud • Due to its increasing scarcity and uneven distribution across the globe, water is gradually becoming a geopolitical resource, influencing the power of nations.\ud The described developments raise the question of what kind of institutional arrangements could be developed to cope with the global dimension of water issues. A few possible directions are identified in an explorative analysis: an international protocol on full-cost water pricing, a water label for water-intensive products, a disposal tax on goods that will cause water pollution in their waste stage (to be used for pollution prevention and\ud control), international nutrient housekeeping, minimum water rights, maximum allowable water footprints, and tradable water footprint permits

The effect of distant large scale structure on weak lensing mass estimates

We quantify the uncertainty in weak lensing mass estimates of clusters of galaxies, caused by distant (uncorrelated) large scale structure along the line of sight. We find that the effect is fairly small for deep observations (20<R<26) of massive clusters (sigma=1000 km/s) at intermediate redshifts, where the bulk of the sources are at high redshifts compared to the cluster redshift. If the lensing signal is measured out to 1.5 h_{50}^{-1} Mpc the typical 1sigma relative uncertainty in the mass is about 6%. However, in other situations the induced uncertainty can be larger. For instance, in the case of nearby clusters, such as the Coma cluster, background structures introduce a considerable uncertainty in the mass, limiting the maximum achievable S/N-ratio to \sim 7, even for deep observations. The noise in the cluster mass estimate caused by the large scale structure increases with increasing aperture size, which will also complicate attempts to constrain cluster mass profiles at large distances from the cluster centre. However, the distant large scale structure studied here can be considered an additional (statistical) source of error, and by averaging the results of several clusters the noise is decreased.Comment: accepted for publication in Astronomy and Astrophysics 11 pages, 9 figure

Weak lensing constraints on galaxy halos

Weak gravitational lensing has become an important tool to study the properties of dark matter halos around galaxies, thanks to the advent of large panoramic cameras on 4m class telescopes. This area of research has been developing rapidly in the past few years, and in these proceedings we present some results based on the Red-Sequence Cluster Survey, thus highlighting what can be achieved with current data sets. We present results on the measurement of virial masses as a function of luminosity and the extent of dark matter halos. Much larger surveys are underway or planned, which will result in an impressive improvement in the accuracy of the measurements. However, the interpretation of future results will rely more and more on comparison with numerical simulations, thus providing direct tests of galaxy formation models.Comment: 8 pages, to appear in Proc. XXIst IAP Colloquium "Mass Profiles and Shapes of Cosmological Structures", Paris 4-9 July 2005 (EAS Publications Series, G. Mamon, F. Combes, C. Deffayet, B. Fort eds.

Integrated optics refractometry: sensitivity in relation to spectral shifts

A new variant of the Vernier-effect based sensor reported in ref. 1 is introduced. Both sensor types may show a huge index induced spectral shift. It will be shown in a poster presentation that with such sensors, as well as with surface plasmon based sensors, the constraints on the spectral resolution of the read out are strongly relaxed, but the sensitivity is not increased (unlike what is often reported in the literature)

An economic method for the solution of the scalar wave equation for arbitrarily shaped optical waveguides

The discrete sine method, in which the basis functions consist of sine functions defined on a set of parallel discretization lines, is discussed. The method is a combination of a scalar version of the finite difference method and sine method. The choice of the basis set leads for the eigenvalue equation to be solved, to a sparse matrix with a small bandwidth. As a consequence, the propagation constant of guided modes in optical waveguides may be calculated with short computation times and low storage needs. Results obtained with the method for three different wave guiding structures are compared with those of other method

Water Neutral: Reducing and Offsetting the Impacts of Water Footprints

During the past few years the water footprint has started to receive recognition as a useful indicator of water use, within both governments (UNESCO, 2006) and non-governmental organizations (Zygmunt, 2007; WWF, 2008), as well as within businesses (WBCSD, 2006; JPMorgan, 2008) and media (The Independent, 2008; The Economist, 2008; Discover Magazine, 2008). The increased interest in the water-footprint concept has prompted the question about what consumers and businesses can do to reduce their water footprint. Several instruments have been proposed, including a water label for water-intensive products, an international water-pricing protocol, an international business agreement on water-footprint accounting, and a Kyoto-protocol-like agreement on tradable water-footprint permits (Hoekstra, 2006; Verkerk et al., 2008). Another concept that has been proposed is that of 'water neutrality'. The idea behind the concept is to see whether humans can somehow neutralise or offset their 'water footprint'. The question is very general and interesting from the point of view of both individual consumers and larger communities, but also from the perspective of governments and companies. The aim of this report is to critically discuss the water-neutral concept. It first discusses the water-footprint concept, because water neutrality is all about reducing and offsetting the impacts of water footprints (Figure 1.1). Subsequently, the report elaborates the idea of water neutrality. After a generic discussion of the concept, it is discussed what water neutrality means for a product, an individual consumer or a business. Finally, the concept is critically analysed in terms of its strengths and weaknesses

Water Scarcity in the Zambezi Basin in the Long-Term Future: A Risk Assessment

The aim of this paper is to explore possible futures for the Zambezi basin and to estimate the risks of different water management strategies. Existing uncertainties are translated into alternative assumptions. The risk of a certain management strategy, which has been developed under a given set of assumptions, is analysed by applying alternative assumptions. For the exploration of possible futures, a dynamic simulation model is used. Three ‘utopias’ and a number of ‘dystopias’ are considered. A utopia is based on a coherent set of assumptions with respect to world-view (how does the world function), management style (how do people respond) and context (exogenous developments). A dystopia evolves if some assumptions are taken differently. Using the risk assessment method described, the paper reflects on the water policy priorities earlier proposed in an expert meeting held in Harare. It is shown that in only one out of the nine cases putting the ‘Harare priorities’ into practice will work out effectively and without large tradeoffs. It is concluded that minimising risks would require a radical shift from supply towards demand policy.\u

The global dimension of water governance: why the river basin approach is no longer sufficient and why cooperative action at global level is needed

When water problems extend beyond the borders of local communities, the river basin is generally seen as the most appropriate unit for analysis, planning, and institutional arrangements. In this paper it is argued that addressing water problems at the river basin level is not always sufficient. Many of today’s seemingly local water issues carry a (sub)continental or even global dimension, which urges for a governance approach that comprises institutional arrangements at a level beyond that of the river basin. This paper examines a number of arguments for the thesis that good water governance requires a global approach complementary to the river basin approach. Subsequently, it identifies four major issues to be addressed at global scale: Efficiency, equity, sustainability and security of water supply in a globalised world. Finally, the paper raises the question of what kind of institutional arrangements could be developed to cope with the global dimension of water issues. A few possible directions are explored, ranging from an international protocol on full-cost water pricing and a water label for water-intensive products to the implementation of water footprint quotas and the water-neutral concept

The water footprint of food

The international trade in agricultural commodities at the same time\ud constitutes a trade with water in virtual form. Water in external areas\ud has been used to produce the food and feed items that are imported.\ud The water footprint of a good or a service is the total amount of water,\ud external and internal, that is required to produce it. The concept can be\ud used to calculate and compare the strain on water resources resulting\ud from different options. It can also be extended to provide water budgets\ud for whole nations or continents