Evaluating the Global Environment Facility: A goodwill gesture or a serious attempt to deliver global benefits?

Over its 17 years, the UN's Global Environment Facility (GEF) has allocated US $7.5 billion intended to develop and implement scientifically and socially credible solutions to key global environmental problems such as climate change, biological diversity loss and degradation of transboundary aquatic systems. We studied 906 GEF projects to analyse the challenges that it is facing in delivering solutions that are likely to be sustainable in the long-term. The research included desk reviews of relevant documents and follow-up interviews with a wide range of stakeholders. Some of the challenges the GEF faces are deeply rooted in temporal and spatial mismatches of scale between human economies and their environmental consequences and the strongly sectoral way current society is managed. We conclude that the GEF obtained impressive results for tackling problems of limited complexity and easily quantified benefits but progress is slower on more complex and less tangible problems impeding sustainable development. Potentially, the GEF could enable adaptive management through a ‘learning by doing’ process, transforming it into an innovative mechanism for delivering global benefits. Continued emphasis on ‘easy wins’ would not allow it to achieve this goal.     

Modeling Uranium Transport in Koongarra, Australia: The Effect of a Moving Weathering Zone

Natural analogues are an important source of long-term data and may be viewed as naturally occurring experiments that often include processes, phenomena, and scenarios that are important to nuclear waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region of Australia is one of the best-studied natural analogue sites. The deposit has been subjected to chemical weathering over several million years, during which many climatological, hydrological, and geological changes have taken place, resulting in the mobilization and spreading of uranium. Secondary uranium mineralization and dispersed uranium are present from the surface down to the base of the weathering zone, some 25 m deep. In this work, a simple uranium transport model is presented and sensitivity analyses are conducted for key model parameters. Analyses of field and laboratory data show that three layers can be distinguished in the Koongarra area: (1) a top layer that is fully weathered, (2) an intermediate layer that is partially weathered (the weathering zone), and (3) a lower layer that is unweathered. The weathering zone has been moving downward as the weathering process proceeds. Groundwater velocities are found to be largest in the weathering zone. Transport of uranium is believed to take place primarily in this zone. It appears that changes in the direction of groundwater flow have not had a significant effect on the uranium dispersion pattern. The solid-phase uranium data show that the uranium concentration does not significantly change with depth within the fully weathered zone. This implies that uranium transport has stopped in these layers. A two-dimensional vertically integrated model for transport of uranium in the weathering zone has been developed. Simulations with a velocity field constant in time and space have been carried out, taking into account the downward movement of this zone and the dissolution of uranium in the orebody. The latter has been modelled by a nonequilibrium relationship. In these simulations, pseudo-steady state uranium distributions are computed. The main conclusion drawn from this study is that the movement of the weathering zone and the nonequilibrium dissolution of uranium in the orebody play an important role in the transport of uranium. Despite the fact that the model is a gross simplification of what has actually happened in the past two million years, a reasonable fit of calculated and observed uranium distributions was obtained with acceptable values for the model parameters.     

Exposed sandy beaches as semi-closed ecosystems

On the basis of various lines of evidence, mostly coming from exposed sandy beaches in Southern Africa, it is postulated that under certain conditions high energy sandy beaches and their adjacent surf zones may function as viable ecosystems. Where surf zones are reasonably broad and shallow, cellular circulation patterns predominate and these tend to retain nutrients generated by the macrofauna and interstitial fauna of the beach. These nutrients may then cause blooms of surf zone phytoplankton which in turn serve as food for macrofauna filter feeders. With the perimeter of the circulation cells of the surf zone forming its marine boundary, the beach and surf zone may together be considered an ecosystem with surf phytoplankton the primary producers, beach macrofauna the consumers and interstitial fauna the decomposers.     

The Interstitial Environment of Sandy Beaches

Abstract. The interstitial system of sandy beaches is lacunar and has its dimensions defined by the sand granulometry. It can be described by features such as pore size, porosity, permeability, and water content. The most important process occurring in this system, water filtration, is driven by inputs of freshwater from groundwater discharge, and inputs of seawater by tides, wave run-up, and subtidal wave pumping. Reflective beaches have seawater input effected mainly by waves; they filter large water volumes with short residence times. Dissipative beaches display the opposite patterns, slowly filtering small volumes input by tides. Flow patterns and their effects on interstitial climate are described. The water table of the beach moves in response to groundwater discharge, tides, and waves and influences erosion/accretion processes on the beach face: a high water table promotes erosion. A series of moisture zones can be recognised from the dry surface sand at upper tide levels, to permanently saturated sand below the low tide water table, namely: a stratum of dry sand, a stratum of retention, a stratum of resurgence, and stratum of saturation. Interstitial chemistry is briefly described in terms of salinity changes, organic loads, oxygen content, and nutrient cycling. It is concluded that the interstitial environment of sandy beaches spans a continuum between physically and chemically controlled extremes: the former condition occurs on coarse sand reflective beaches, which experience low organic inputs and high filtration rates of large water volumes — resulting in powerful hydrodynamic forces; the latter occurs on dissipative beaches of fine sand, which are subject to high organic inputs and low filtration volumes — resulting in stagnation and steep vertical chemical gradients. Many intermediate situations occur and these are more favourable to interstitial life than either of the extremes.     

Deformation and fault activity in space and time in high-resolution numerical models of doubly vergent thrust wedges

A discrete-element model is used to investigate the manner in which deformation and fault activity change in space and time during the development of a doubly vergent thrust wedge in the upper crust. Deformation is a result of shortening at a subduction slot in the base of the model, a configuration which produces a dynamic backstop within the cohesionless, frictional cover material. A series of experiments with differing basal (decollement) friction are performed. The distinct manners in which thrust wedges grow, and the variability of fault development and activity in space and time, are then examined. Both predicted large-scale wedge geometries and individual fault-fold structures are similar to those observed in sandbox models, and show the complex manner in which shortening is accommodated and localized during the development of the thrust wedge. When compared to a sandbox model with similar boundary conditions, model results are strikingly similar. In all cases, deformation initiates above the subduction slot with the formation of an axial zone; the wedge is then developed by displacement on a retro-wedge thrust and propagation of deformation into the pro-wedge region. Models with low coefficients of basal friction typically develop wide, shallow wedges with distributed, spaced deformation and rather symmetric, box-like structures; whereas those with high coefficients of basal friction develop narrower, steeper wedges, consisting of a series of stacked, pro-wedge thrust sheets, and a high-displacement retro-wedge thrust. In general, fault initiation and linkage is extremely complex in our models, with several smaller faults operating until linkage occurs to form a major through-going structure. Of particular interest is the observation that many of the faults do not develop at the basal decollement and propagate upwards through the cover but rather initiate at high levels in the cover and propagate/link downwards with other, deeper structures. Results also indicate the utility of the discrete-element approach in modelling large-displacement, complex deformation of geological materials.     

Landscape change analysis and assessment (case studies in Slovakia and Bulgaria)

Landscape change assessment was conducted in selected areas of Slovakia and Bulgaria in 1990–2000 using CORINE land cover (CLC) data layer analysis. Assessment of causes that led to these changes was undertaken, with an emphasis on those that determined the extensification of agriculture. The LC data were obtained under the CLC90 and I&CLC2000 projects, jointly managed by the European Environment Agency in Copenhagen, Denmark and the Joint Research Centre of the European Commission in Ispra, Italy. The CLC1990-2000-changes data layer was generated by overlaying the CLC90 and CLC2000 data layers for change in areas of a minimum 5 ha. The analysed causes of changes (driving forces) were then classified. Land cover (LC) changes characterizing urbanization processes occurred only in the Trnava and Tatras areas. Intensification of agriculture was also higher in these two areas. LC changes characterizing the extensification of agriculture were dominant in Plovdiv and Trnava. Deforestation and forestation were identified in all areas (Trnava, Tatras, Plovdiv, and Burgas). The basic reasons of these changes were related to the transformation of national economies from being centrally planned to market controlled, following the fall of socialism and before the countries joined the European Union.     

Broadband convex impedance ground planes for multi-system GNSS reference station antennas

Common choke ring ground planes are known to contribute to undesirable antenna pattern narrowing in the elevation plane which is associated with difficulties of tracking low elevation satellites. Also known is the comparatively narrow frequency bandwidth of the choke grooves structure. As an alternative, using a convex impedance ground plane has been suggested for full-spectrum GNSS applications. With such ground planes a pin structure is utilized instead of choke grooves to allow a frequency bandwidth increase. A semi-spherical shape of the ground plane is shown to provide increased antenna gain for low elevation angles. Theoretical performance estimates along with experimental test data have been provided.     

Experimental impact features in Stardust aerogel: How track morphology reflects particle structure,composition, and density

Abstract– The Stardust collector shows diverse aerogel track shapes created by impacts of cometary dust. Tracks have been classified into three broad types (A, B, and C), based on relative dimensions of the elongate “stylus” (in Type A “carrots”) and broad “bulb” regions (Types B and C), with occurrence of smaller “styli” in Type B. From our experiments, using a diverse suite of projectile particles shot under Stardust cometary encounter conditions onto similar aerogel targets, we describe differences in impactor behavior and aerogel response resulting in the observed range of Stardust track shapes. We compare tracks made by mineral grains, natural and artificial aggregates of differing subgrain sizes, and diverse organic materials. Impacts of glasses and robust mineral grains generate elongate, narrow Type A tracks (as expected), but with differing levels of abrasion and lateral branch creation. Aggregate particles, both natural and artificial, of a wide range of compositions and volatile contents produce diverse Type B or C shapes. Creation of bulbous tracks is dependent upon impactor internal structure, grain size distribution, and strength, rather than overall grain density or content of volatile components. Nevertheless, pure organic particles do create Type C, or squat Type A* tracks, with length to width ratios dependent upon both specific organic composition and impactor grain size. From comparison with the published shape data for Stardust aerogel tracks, we conclude that the abundant larger Type B tracks on the Stardust collector represent impacts by particles similar to our carbonaceous chondrite meteorite powders.