The nexus approach to water–energy–food security: an option for adaptation to climate change

Developing countries face a difficult challenge in meeting the growing demands for food, water, and energy, which is further compounded by climate change. Effective adaptation to change requires the efficient use of land, water, energy, and other vital resources, and coordinated efforts to minimize trade-offs and maximize synergies. However, as in many developing countries, the policy process in South Asia generally follows a sectoral approach that does not take into account the interconnections and interdependence among the three sectors. Although the concept of a water–energy–food nexus is gaining currency, and adaptation to climate change has become an urgent need, little effort has been made so far to understand the linkages between the nexus perspective and adaptation to climate change. Using the Hindu Kush Himalayan region as an example, this article seeks to increase understanding of the interlinkages in the water, energy, and food nexus, explains why it is important to consider this nexus in the context of adaptation responses, and argues that focusing on trade-offs and synergies using a nexus approach could facilitate greater climate change adaptation and help ensure food, water, and energy security by enhancing resource use efficiency and encouraging greater policy coherence. It concludes that a nexus-based adaption approach – which integrates a nexus perspective into climate change adaptation plans and an adaptation perspective into development plans – is crucial for effective adaptation. The article provides a conceptual framework for considering the nexus approach in relation to climate change adaptation, discusses the potential synergies, trade-offs, and offers a broader framework for making adaptation responses more effective.

Policy relevance

This article draws attention to the importance of the interlinkages in the water, energy, and food nexus, and the implications for sustainable development and adaptation. The potential synergies and complementarities among the sectors should be used to guide formulation of effective adaptation options. The issues highlight the need for a shift in policy approaches from a sectoral focus, which can result in competing and counterproductive actions, to an integrated approach with policy coherence among the sectors that uses knowledge of the interlinkages to maximize gain, optimize trade-offs, and avoid negative impacts.     

Validation of the ESA CCI soil moisture product in China

The quality of a newly merged soil moisture product (ECV_SM v0.1) from active and passive microwave sensors has attracted widespread international attention. The performance evaluation of this product will benefit studies on climate, meteorology, agriculture, hydrology, ecology and the environment. In this study, meteorological station data and the Noah soil moisture product were used to validate the ECV_SM product in China. First, some conventional statistical measures, such as correlation coefficients, bias, root mean square difference (RMSD) and mean relative error (MRE), were computed to describe the level of agreement between the meteorological station data and ECV_SM values. The accuracy was moderately high (the correlation was significant at the 0.05 level), although the two datasets differed slightly for various types of land cover. Compared with cropland and urban and built-up areas, the performance of ECV_SM was best in grassland regions. Second, the triple collocation technique was used to assess the random error in the meteorological station data, Noah soil moisture product and ECV_SM product. The mean errors in these three datasets were 0.108, 0.079 and 0.075 m³ m⁻³, respectively, on July 8, 2010 and 0.099, 0.061 and 0.059 m³ m⁻³, respectively, on October 8, 2010. Only two days of data were used for the triple collocation test as a representative, but this cannot precisely indicate that the test results on any other day correspond with the test results on these two days. Additionally, a trend analysis of ECV_SM during 2003–2010 was carried out using the Mann–Kendall trend test.     

Great new insights from failed experiments,unanticipated results and embracing controversial observations

Experimental data and observations, whether telescopic or analytical, are never wrong, though data derived from such sources can be misinterpreted or applied inappropriately to derive conclusions that are incorrect. Given that nature always behaves according to the laws of physics and chemistry, rather than according to currently popular models and theories, experimental results should always be considered correct even when the results are far from those that one might initially expect. We discuss a number of cases where the results of experiments, even one carried out as a simple calibration measure, produced wildly different results that generally required many years of effort or contemplation to understand. On the positive side, exploration of the circumstances that produced the “errant” results often led to new and interesting insights concerning processes that might occur in natural environments and that were well worth the effort involved.Specifically, we show how an experiment that “failed” due to a broken conductor led to experiments that made the first refractory oxide solids containing mass independently fractionated oxygen isotopes and to 1998 predictions of the oxygen isotopic composition of the sun that were confirmed by the analysis of Genesis samples in 2011. We describe a calibration experiment that unexpectedly produced single magnetic domain iron particles. We discuss how tracking down a persistent source of “contamination” in experiments intended to produce amorphous iron and magnesium silicate smokes led to a series of studies on the synthesis of carbonaceous grain coatings that turn out to be very efficient Fischer–Tropsch catalysts and have great potential for trapping the planetary noble gases found in meteorites. We describe how models predicting the instability of silicate grains in circumstellar environments spurred new measurements of the vapor pressure of SiO partially based on previous experiments showing unexpected but systematic non-equilibrium behavior instead of the anticipated equilibrium products resembling meteoritic minerals. We trace the process that led from observations of the presence of crystalline minerals detected in the comae of some comets to the 1999 prediction of large-scale circulation of materials from the hot, innermost regions of the solar nebula out to the cold dark nebular environments where comets form. This large-scale circulation was ultimately confirmed by analyses of highly refractory Stardust samples collected from the Kuiper Belt Comet Wild 2. Finally we discuss a modern and still unresolved conflict between the assumptions built into three well known processes: the CO Self Shielding Model for mass independent isotopic fractionation of oxygen in solar system solids, rapid and thorough mixing within the solar nebula, and the efficient conversion of CO into organic coatings and volatiles on the surfaces of nebular grains via Fischer–Tropsch-type processes.     

Geographies of high frequency trading – Algorithmic capitalism and its contradictory elements

This paper investigates the geographies of high frequency trading. Today shares shift hands within microseconds, giving rise to a form of financial geographies termed algorithmic capitalism. This notion refers to the different spatio-temporalities produced by high frequency trading, under the valuation of time. As high frequency trading accelerates financial markets, the paper examines the spatio-temporalities of automated trading by the ways in which the speed of knowledge exploitation in financial markets is not only of interest, but also the expansion between different temporalities. The paper demonstrates how the intensification of time–space compression produces radical new dynamics in the financial market and develops information rent in HFT as convertible to a time rent and a spatio-temporal rent. The final section discusses whether high frequency trading only responds to crises in microseconds or constitutes them. It argues that automated trading will not only contribute to accelerate crises, but also deepen them by the ways in which it differentiates the dynamics between financial, fixed and productive capital.     

Spectral characteristics of the Gawler Range Volcanics in drill core Myall Creek RC1

Traditional core-logging methods in conjunction with spectral scanning techniques have been used to log volcanic successions of the lower Gawler Range Volcanics. The open-file drill core Myall Creek RC 1 was re-logged and scanned using HyLogger? core scanning technologies as a part of the Geological Survey of South Australia's Southern Gawler Rangers mapping program and the Mineral System Drilling Program. Myall Creek RC 1 is one of the key stratigraphic drill cores for the region, owing to the intersection of a large section of the Gawler Range Volcanics. Spectral characterisation of the Eucarro Rhyolite revealed differential weathering of plagioclase phenocrysts, while high-resolution imagery and spectral results were used to log new basaltic flows and small flow features in the Roopena Basalt. The composition and distribution of feldspars in the unnamed lower Gawler Range Volcanic units were used to aid traditional logging of visually similar lithologies. A spectral scalar, the felsic–mafic index, was used to identify unusual features in the unnamed sequence and was found to identify iron oxides as either fracture coatings or finely disseminated in the matrix of the sample. Iron oxides were also used to identify features within lithological units, which were difficult to discern visually, especially the layers in the deepest layered ignimbrite at the end of the drill core.     

National Virtual Core Library HyLogging data and Ni–Co laterites: a mineralogical model for resource exploration,extraction and remediation

The National Virtual Core Library (NVCL) HyLogging core-scanning system generates mineralogical information from visible, short-wave infrared and thermal infrared spectroscopic data. Currently, HyLogging data are freely available for more than 1500 drill holes via the AuScope Discovery Portal and various Geological Survey websites. With any new technology, there is commonly a lag between provision and take-up by users that can be aided by the publication of case studies in the scientific literature. This paper uses the Mt Davies nickel–cobalt (Ni–Co) laterite deposits, located in northwest South Australia, as a case study to assess the accessibility and representation of HyLogger data and provides an example of its application to all aspects of resource mining: exploration, extraction and processing, and remediation. In this study, we combine HyLogger-derived scalars indicating Fe-oxide and clay mineralogy with historical geological logs and assay data. In general, background Ni grades (<0.1 wt%) are linked to the presence of montmorillonite + hematite ± goethite, moderate grades (0.1–1.0 wt%) are associated with goethite ± nontronite ± saponite ± kaolinite ± montmorillonite, and higher grades (1.0–2.0 wt%) are coincident with goethite and minimal clay alteration, suggesting that goethite hosts Ni mineralisation. Gibbsite, where it occurs, is found immediately above zones of moderate to high Ni grades and may be an important proximal indicator mineral of nickeliferous laterite. Such a case study serves to suggest opportunities for further data modelling and search and query functionality that could facilitate increased use of this important digital geoscience data resource by the Australian minerals industry for all aspects of resource exploitation: exploration, extraction, processing, and environmental remediation.     

Numerical simulations of wave–current flow in an ocean basin

Wave–current flow is a phenomenon that is present in many practical engineering situations. Over the past several decades, this type of flow has been increasingly investigated under controlled laboratory conditions. This paper presents a numerical study of wave–current flow in the ocean basin of the LabOceano (COPPE/UFRJ). A homogeneous multiphase model based on the RANS equations and the k–ɛ turbulence model implemented in ANSYS-CFX code were used. A cross section of the ocean basin was represented. A regular wave with a height of 0.08 m and a period of 1.80 s (i.e., a wave steepness of H/L = 0.016), propagating on favourable currents, was simulated. The behaviour of the free surface elevation over time and the streamlines along the basin for wave and wave–current flows were presented. The numerical results were compared to the non-viscous theory given by the Rayleigh equation applied to the problem of wave–current interaction. Good agreement was found between the wave length estimated by the numerical results and the analytical solutions, with a deviation of less than 2%.     

Fatigue analysis of offshore well conductors: Part II – Development of new approaches for conductor fatigue analysis in clays and sands

This paper, Part II, presents two soil modelling approaches developed specifically for fatigue analysis of well conductors. The first approach uses Winkler springs and can account for soil damping. The second approach is based on continuum soil mechanics and uses the kinematic hardening principles. They focus on cyclic soil behaviour at the steady-state condition. The paper demonstrates appropriateness of the approaches in predicting fatigue damage through comparisons with the centrifuge fatigue lives measured from the Series 1 tests in NC to lightly OC kaolin clay. It also presents and discusses the analyzed data and the fatigue lives measured from the Series 2 (medium-dense sand), Series 3 (NC to lightly OC GoM clay), and Series 4 (OC natural clay) tests. Finally, soil models (based on the first approach) are presented for fatigue analysis of well conductors installed in NC to lightly OC clays, over-consolidated (OC) clays and medium-dense sands, and their ability to predict conductor fatigue damage under wide range of loading conditions is demonstrated. Overall, the accuracy of fatigue life predictions using these novel soil models is very high – generally within about a few percentages of the measured values.     

Fatigue analysis of offshore well conductors: Part I – Study overview and evaluation of Series 1 centrifuge tests in normally consolidated to lightly over-consolidated kaolin clay

An important aspect of deepwater well integrity assurance is conductor fatigue analysis under environmental loads acting on the riser system during drilling operation. Fatigue damage arises from stress changes in a structure due to cyclic loading. In practice, the lateral cyclic soil response is typically modelled using Winkler p–y springs. An appropriate soil model for conductor–soil interaction analysis is the one based on which the absolute magnitudes of stresses and their changes can accurately be predicted for well integrity evaluation. The API recommendations for p–y curves, which are often used for conductor–soil interaction analysis, have originally been developed for piled foundation and are inappropriate for well fatigue analysis. To that end, an extensive study involving four series of centrifuge model tests and FE numerical analyses was conducted to fundamentally study conductor–soil interaction under a wide spectrum of loading conditions. The tests simulated conductor installations in normally to over consolidated clays, and medium-dense clean sands. Soil models were developed specifically for conductor fatigue analysis for each of the soil types. The test results and soil models are presented in two papers. The first paper, Part I, presents an overview of the study and first series tests in normally to lightly over-consolidated kaolin clay and discusses the observations made with regards to monotonic and cyclic soil resistances and their relationship to conductor fatigue modelling. The second paper, Part II, presents centrifuge test results in normally to lightly over-consolidated Golf of Mexico (GoM) clay, over-consolidated natural clay and medium-dense clean sands along with the respective soil models developed for conductor fatigue damage prediction. Overall, the accuracy of fatigue life predictions using these novel soil models is very high – generally within about a few percentage of the measured values.     

The emplacement of in situ greenstones in the northern Hidaka belt: The tectonic relationship between subduction of the Izanagi–Pacific ridge and Hidaka magmatic activity

Greenstone bodies emplaced upon or into clastic sediments crop out ubiquitously in the Hidaka belt (early Paleogene accretionary and collisional complexes exposed in the central part of northern Hokkaido, NE Japan), but the timing and setting of their emplacement has remained poorly constrained. Here, we report new zircon U–Pb ages for the sedimentary complexes surrounding these greenstones. The Hidaka Supergroup in the northern Hidaka belt is divided into four zones from west to east: zones S, U, and R, which contain in situ greenstones; and zone Y, which does not. Detrital zircons in zones S, U, and R have early Eocene U–Pb ages (55–47 Ma) and these strata are intruded by early Eocene granites (46–45 Ma), indicating that they were deposited between 55 and 46 Ma. Therefore, in situ greenstones in the northern Hidaka belt can only be explained by the subduction of the Izanagi–Pacific Ridge during 55–47 Ma. In contrast, the deposition of zone Y (the Yubetsu Group, younging to the west) began by 73–71 Ma, indicating that the accretionary prism in front of the paleo-Kuril arc formed at the same time as that in the Idonnappu zone and grew continuously until 48 Ma. The plutonic rocks that intruded the Hidaka belt are roughly divided into three stages: (1) early Eocene granites intruded the northern Hidaka belt at 46–45 Ma, during subduction of the Izanagi–Pacific Ridge; (2) the upper sequence of the Hidaka metamorphic zone was metamorphosed by magmatism at 40–37 Ma associated with the collision of the paleo-Kuril arc and NE Asia; and (3) younger granites intruded the entire Hidaka belt at 20–17 Ma in association with asthenospheric upwelling caused by back-arc expansion.