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Atmospheric carbon dioxide enrichment (eCO 2 ) can enhance plant carbon uptake and growth 1-5 , thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO 2 concentration 6 . Although evidence gathered from young aggrading forests has generally indicated a strong CO 2 fertilization effect on biomass growth 3-5 , it is unclear whether mature forests respond to eCO 2 in a similar way. In mature trees and forest stands 7-10 , photosynthetic uptake has been found to increase under eCO 2 without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO 2 unclear 4,5,7-11 . Here using data from the first ecosystem-scale Free-Air CO 2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responded to four years of eCO 2 exposure. We show that, although the eCO 2 treatment of +150 parts per million (+38 per cent) above ambient levels induced a 12 per cent (+247 grams of carbon per square metre per year) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for half of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO 2 , and challenge the efficacy of climate mitigation strategies that rely on ubiquitous CO 2 fertilization as a driver of increased carbon sinks in global forests.

At Barangaroo South on Sydney's central business district waterfront, Australia, Lend Lease is working with the New South Wales government on the A$6 billion (£4 billion) transformation of a former container port into a thriving business, residential and leisure precinct. The vision is that Barangaroo South will enhance Sydney's position as an internationally appealing, globally competitive, environmentally sustainable city. The development will be Australia's first large-scale carbon dioxide neutral precinct. Barangaroo South will feature three commercial towers ranging in height from 39 to 49 storeys, sharing a common, two-level basement to be retained around its perimeter by an approximately 770 m long diaphragm wall, socketed into Sydney sandstone. As the basement excavation will be below sea level, it is essential that the site retention wall for the basement also acts as a cut-off against groundwater ingress. This paper provides an overview of the design and construction challenges facing the installation of the diaphragm wall and the innovative solutions adopted to overcome these challenges. [ABSTRACT FROM AUTHOR]

This paper evaluates the teaching and learning outcomes from a first-year project-based engineering course at the University of New South Wales. The students worked in teams to design and build a device to sequester "CO2" into a reservoir. We present our observation of the peer assessments, performance prediction and diversity of the students. We found that some teams collaborated more effectively than others. We quantified this effectiveness using an online peer assessment that enables students to rate the performance of their teammates. These ratings were incorporated into the assignment of individual marks for group assignments. The analysis of the marks students achieved for various assessments and components of the course is presented. We observed that female students tended to out-perform their peers in both individual and team assessments, and students who did well in individual components of the course also did well in the team components. The use of early assessments to predict performance in later assessments seems to be difficult. However, there is a strong connection between students' results for their design proposal and their results for the final design work. We are able to show statistically a signifi cant improvement for marks for presentations but not for report writing. Anonymous surveys showed that about 90% of students were satisfied with their experience of the course. Students found this course to be challenging and enjoyable, giving them a good start in developing their skills as engineers. [ABSTRACT FROM AUTHOR]

• Scoping economic comparison of pipeline and ship CO2 transport in eastern australia. • CO2 captured from iron and steel plant located in port Kembla, NSW. • Estimated costs are lowest for the hub pipeline transport. • The shipping transport option presented highest cost. • There is still a case to be made for ship transport if the project duration is short. The main source of CO 2 emissions in an integrated steel manufacturing plant comes from the need to use a carbon source, often coal, in the steel making process. Amongst the pathways for reducing CO 2 emissions is the application of carbon capture, transport and storage (CCS) technologies. This paper presents a scoping-level economic evaluation of transport and storage location options for CO 2 captured from an iron and steel plant located in Port Kembla, NSW, Australia. Pipeline (single and hub) and ship transport of CO 2 , and two injection locations are considered. Estimated costs are lowest for the hub transport case injecting at the Gippsland basin (∼35% lower than for single source cases) and highest for the shipping case. For the single-source cases, transport via pipeline to the Darling basin is slightly more attractive in terms of unit costs. The hub transport cases were between two-thirds and half of the cost of the shipping case. Although the shipping transport option presented the highest cost of the cases considered, there is still a case to be made for ship transport if the project duration is short. [ABSTRACT FROM AUTHOR]

Abstract: The efficacy of technologies to reduce enteric CH4 emissions from ruminants are typically evaluated on individual animals with little consideration of enterprise scale impacts. While impacts of the many rumen manipulations being studied are hard to anticipate, there is adequate information to assess impacts of farm management changes and potential animal genetic changes on whole farm productivity and enteric CH4 emissions. Seven common sheep production systems grazing an annual pasture in central New South Wales, Australia, were modelled using GrassGro® (version 3.1.2). A range of animal management and animal genetic strategies were examined for their impact on total enteric emissions, emission intensity (i.e., kg CO2 equivalent/kg live weight (LW) of animal sold) and profit. Within enterprises, mitigation options were compared at their respective sustainable economic optimum stocking rate as it was assumed that farmers would seek to achieve the highest sustainable profit achievable from a finite land resource. Management options considered were choice of lambing time, mating ewes for the first time as lambs rather than yearlings, and feeding lambs to reduce time to slaughter. The potential for using selective animal breeding was also tested, with sheep physiological parameters being altered in GrassGro® to represent genetic improvement in fecundity, LW gain, residual feed intake and CH4 yield. In general, the management choices delivering lowest emission intensity were also the most profitable within sustainability constraints. Mating maiden ewes as lambs was only effective in reducing enterprise emissions intensity in self-replacing flocks (i.e., no purchased replacements). When stocking rates were at the sustainable economic optimum, choice of enterprise or management had little influence on total enteric emissions from the enterprise. If decisions are guided solely by economics, farmers are likely to continue with similar levels of production (and emissions) until a price on enteric CH4 emissions makes the sheep enterprise unprofitable, or an alternative more profitable enterprise than sheep grazing emerges. Improving animal genetics for residual feed intake or CH4 yield offers opportunity to reduce enterprise emissions, but industry progress toward higher genetic merit for these traits is expected to be slow due to relatively low heritability and competing economic imperatives for progress in other traits. This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. [Copyright &y& Elsevier]

Advancing our understanding of the ocean's role in modulating atmospheric carbon dioxide interannual variability is important but limited by the lack of temporal ocean CO2 observations throughout most of the world's oceans. In particular, the role of the coastal ocean for interannual variability of CO2 is unknown, but expected to be large given the dynamics of land to ocean CO2 exchanges. Two coastal hydrographic time series stations at Port Hacking off Sydney, Australia, have collected and measured hydrographic properties (temperature, salinity, nitrate, phosphate, and silicate) since 1942. Here I examine the potential to use empirical relationships derived from nearby discrete CO2 measurements to diagnose CO2 interannual variability at the Port Hacking time series station. I test the approach by predicting interannual variability of CO2 at the Bermuda Time Series Station (BATS) in the North Atlantic between 1988 and 2008 and show the method captures 78% of the observed interannual variability found at BATS. I further use oxygen as a tracer to diagnose the length scales of variability in the southwest Pacific to provide insight into the applicability of the method. After applying the approach at Port Hacking, significant CO2 interannual variability was found (up to ± 30 ppm) that was largely driven by local regional variability in nutrients (nitrate) and temperature with little link to larger modes of variability (SAM or ENSO). Oceanic CO2 was diagnosed to be almost always lower than atmospheric CO2 levels (ΔpCO2 ∼ 10-55 μatm), indicating a quasi-permanent coastal ocean CO2 sink during winter off Sydney. Direct pCO2 measurements taken along the NSW coastline in April and August 2008 confirm the empirical predictions and a wider CO2 sink along Australia's east coast. If extrapolating the Port Hacking CO2 results to the New South Wales coastline, the annual coastal CO2 sink would be about -0.05 Tg C/yr. Both the empirical predictions and direct measurements of CO2 presented here along the Australian east coast support recent reviews suggesting continental shelves act as a significant CO2 sink, at least during autumn and winter. [ABSTRACT FROM AUTHOR]

Existing buildings present the best opportunity for reducing greenhouse gas emissions in developed economies, given that only 2-3% of the building stock is newly built each year. Insights from a post-occupancy evaluation of a large-scale refurbishment project of a head office building in Sydney, Australia, are presented to inform future refurbishment strategies. The study evaluates occupant satisfaction and energy performance, and elicits influencing factors arising from the design process and interventions, ongoing building management, and operational performance. Occupants returned a high level of satisfaction across the range of environmental variables for overall comfort, temperature, lighting, and air quality as well as perceived productivity and health. These outcomes highlight the importance of improving indoor environmental quality for occupants particularly through increased fresh air, daylight, glare control, access to views, and noise management. The positive results reinforce the value of an integrated and user-responsive approach that was adopted for building design, development, and management. The reduction in operational energy (in this project, coupled with carbon reduction) as a consequence of refurbishment and positive user feedback demonstrates the potential to future-proof existing buildings in the context of climate change. Les batiments existants offrent la meilleure possibilite de reduction des emissions de gaz a effet de serre dans les economies developpees, etant donne que les constructions neuves ne representent chaque annee que 2 a 3% du parc bati. Les enseignements retires d'une evaluation apres occupation d'une operation de renovation a grande echelle realisee dans l'immeuble d'un siege social de Sydney, en Australie, sont presentes afin d'inflechir les futures strategies en matiere de renovation. L'etude evalue la satisfaction des occupants et les performances energetiques, et met au jour les facteurs d'influence qui decoulent du processus de conception et des interventions realisees, de la gestion en cours du batiment et des performances de fonctionnement. Les occupants ont exprime un degre de satisfaction eleve sur l'ensemble des variables environnementales concernant le confort global, la temperature, l'eclairage et la qualite de l'air, aussi bien que la productivite et la sante telles qu'ils les ont percues. Ces resultats mettent en evidence le fait qu'il est important d'ameliorer la qualite environnementale interieure pour les occupants, tout particulierement en apportant davantage d'air frais et de lumiere du jour, un plus grand controle de l'eblouissement, un acces accru a des panoramas et une gestion renforcee du bruit. Ces resultats positifs renforcent l'utilite d'une approche integree et sensible aux besoins des utilisateurs, telle qu'elle a ete adoptee pour concevoir, amenager et gerer ce batiment. La reduction de l'energie de fonctionnement (dans cette operation, conjointement avec la reduction du carbone) en consequence de la renovation et du feedback positif des utilisateurs demontre le potentiel de cette approche pour permettre aux batiments existants de bien affronter l'avenir dans le contexte du changement climatique. Mots cles: adaptation, changement climatique, confort, energie, qualite environnementale interieure, conception integree, occupants, evaluation apres occupation, renovation [ABSTRACT FROM AUTHOR]