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Abstract Ground source heat pump (GSHP) systems can provide cost effective and sustainable heating and cooling for buildings while using considerably less fossil fuel than conventional heating and cooling systems. This benefit can be further enhanced by adopting hybrid GSHP (HGSHP) systems wherein the GSHP component provides the baseload thermal energy with the balance provided by conventional systems. This study compares the costs of GSHP and HGSHP systems against conventional systems under a variety of climatic conditions, exemplified by those encountered across Australia, but including conditions encountered elsewhere. The results indicate that the comparative performance of GSHP and HGSHP systems depend on many parameters including climatic conditions, ground conditions, drilling prices and prices of electricity and gas in the regions where the systems are installed. Here we show that in general, adopting GSHP or HGSHP systems over conventional systems allow property owners to pay lower lifetime costs under most climatic conditions and gas to electricity energy price ratios. The results also indicate that conventional systems may be preferred in highly heating or cooling dominant climates and at locations with high drilling costs or low energy prices. In contrast, GSHP and HGSHP systems are preferred in locations with a more balanced climate, lower drilling costs and/or higher energy prices. There is no “one size fits all” rule given the many factors that can influence the lifetime costs. The paper shows that climatic conditions, ground conditions, drilling and energy costs must all be carefully considered when assessing the most cost effective sustainable energy technologies for space heating and cooling.

CO2 emissions from industrial processes and their adverse implications on the climate is of major concern. Carbon capture and storage (CCS), especially using chemical-absorption-based processes, ha...

Abstract The primary objective of this paper is to make a connection between the Singapore story of land transport policy development and the pathway towards sustainable transport planning. Its innovation is to allow a parallel growth in motorization and public transit. The Singapore experience shows how a range of well-coordinated policies including efforts to control the number of cars in both ownership and usage, and at the same time increase the availability and rider-ship of public transit contribute to a sustainable transport system. The Singapore model provides a valuable reference for not only developing an alternative approach towards sustainable transport in countries where motorization is desired but also for understanding the various parameters important to the formulation of management policies. In particular, the paper contends the Singapore experience provides a model for Asian nations and cities.

We present a simple alternative pathway to transform carbon dioxide to perpetually stored solid carbon.

Countries around the world suffer the dramatic impact of earthquakes and other natural hazards reflected in casualties, infrastructure damage, service interruptions, and recovery costs. Although disaster exposure consciousness of electric power systems has increased in recent years, mitigation and adaptation actions, such as reserve scheduling and infrastructure investments, are usually performed without quantitative tools to account for the underlying stochasticity of these events. This article first discusses why an integrated assessment, which incorporates sources of uncertainty (risk) and manages the time-dependency of the recovery process (resilience), should be used to assess the impact of seismic events on electric power systems. Thereafter, a probabilistic methodology that considers the hazard, vulnerability, operation, and recovery of the system is presented. As a case study, the probabilistic seismic resilience of the electric power system of Northern Chile is assessed using different risk measures, including expected annual loss, value at risk, and conditional value-at-risk. Finally, a novel criticality assessment based on these metrics is developed to demonstrate that, for certain networks such as the study case, retrofit of selective components can notably improve the resilience of the complete system to seismic events. For example, if one specific component from the 152 components of the study system is assumed invulnerable, expected annual interruption costs decrease by 8%.

AbstractChromosomal inversion polymorphisms are common in animals and plants, and recent models suggest that alternative arrangements spread by capturing different combinations of alleles acting additively or epistatically to favour local adaptation. It is also thought that inversions typically maintain favoured combinations for a long time by suppressing recombination between alternative chromosomal arrangements. Here, we consider patterns of linkage disequilibrium and genetic divergence in an old inversion polymorphism in Drosophila melanogaster (In(3R)Payne) known to be associated with climate change adaptation and a recent invasion event into Australia. We extracted, karyotyped and sequenced whole chromosomes from two Australian populations, so that changes in the arrangement of the alleles between geographically separated tropical and temperate areas could be compared. Chromosome‐wide linkage disequilibrium (LD) analysis revealed strong LD within the region spanned by In(3R)Payne. This genomic region also showed strong differentiation between the tropical and the temperate populations, but no differentiation between different karyotypes from the same population, after controlling for chromosomal arrangement. Patterns of differentiation across the chromosome arm and in gene ontologies were enhanced by the presence of the inversion. These data support the notion that inversions are strongly selected by bringing together combinations of genes, but it is still not clear if such combinations act additively or epistatically. Our data suggest that climatic adaptation through inversions can be dynamic, reflecting changes in the relative abundance of different forms of an inversion and ongoing evolution of allelic content within an inversion.

Blue carbon ecosystems (BCEs), such as mangroves, tidal marshes, and seagrasses, are attracting interest for their potential to mitigate climate change arising from their high rates of carbon accumulation and the significant carbon stocks in their sediments. However, current sediment carbon sampling methods present a mixture of approaches adopted from paleoenvironmental methods focused on historical reconstruction of carbon accumulation, and from soil science methods developed to provide highly accurate and spatially representative carbon stock measurements. Currently, no international standard method for sediment carbon stock analysis exists. Consequently, current estimates of sediment carbon stock values for BCEs may have large uncertainties due to variable methodology. We reviewed and analysed the methods used 217 studies included in two recent global syntheses of carbon stocks in mangrove forest ecosystems to illustrate a lack of consistency in sediment sampling. We then outline how the choice of study design and field sampling methods can introduce inaccuracies and uncertainties in sediment carbon stock analysis. We conclude with examples of how each of these challenges can be resolved and how greater carbon stock quantification accuracy and higher spatial integration can be achieved for blue carbon ecosystems in the future.

Studies suggest that many species are already living close to their upper physiological thermal limits. Phenotypic plasticity is thought to be an important mechanism for species to counter rapid environmental change, yet the extent to which plastic responses may buffer projected climate change - and what limits the evolution of plasticity - is still unclear. The tolerance-plasticity trade-off hypothesis predicts that the evolution of plasticity may be constrained by a species' thermal tolerance. Empirical evidence is equivocal, but we argue that inconsistent patterns likely reflect problems in experimental design/analysis, limiting our ability to detect and interpret trade-off patterns. Here, we address why we may, or may not see tolerance-plasticity trade-offs and outline a framework addressing current limitations, focusing on understanding the underlying mechanisms.

Abstract The building sector is responsible for significant energy demands. An understanding of where this occurs across the building life cycle is critical for optimal targeting of energy reduction efforts. The energy embodied in a building can be significant, yet is not well understood, especially the on-going ‘recurrent’ embodied energy associated with material replacement and building refurbishment. A key factor affecting this ‘recurrent’ embodied energy is a building's service life. The aim of this study was to investigate the relationship between the service life and the life cycle embodied energy of buildings. The embodied energy of a detached residential building was calculated for a building service life range of 1–150 years. The results show that variations in building service life can have a considerable effect on the life cycle embodied energy demand of a building. A 29% reduction in life cycle embodied energy was found for the case study building by extending its life from 50 to 150 years. This indicates the importance of including recurrent embodied energy in building life cycle energy analyses as well as integrating building service life considerations when designing and managing buildings for improved energy performance.