Chill unit models for blackcurrant (Ribes nigrum L.) cultivars 'Ben Gairn', 'Ben Hope' and 'Ben Tirran'

Temperate-zone crops require a period of winter chilling to terminate dormancy and ensure adequate bud break the following spring. The exact chilling requirement of blackcurrant (Ribes nigrum), a commercially important crop in northern Europe, is relatively unknown. Chill unit models have been successfully utilized to determine the optimum chilling temperature of a range of crops, with one chill unit equating to I h exposure to the optimum temperature for chill satisfaction. Two-year-old R. nigrum plants of the cultivars 'Ben Gairn', 'Ben Hope' and 'Ben Tirran' were exposed to temperatures of -10.1 degrees C. -3.4 degrees C. 0.1 degrees C, 1.5 degrees C, 2.1 degrees C, 3.4 degrees C or 8.9 degrees C (+/- 0.7 degrees C) for durations of 0, 2, 4, 6, 8 or 10 weeks and multiple regression analyses used to determine the optimum temperature for chill satisfaction. (C) 2009 Elsevier B.V. All rights reserved.

Variation in the global-scale impacts of climate change on crop productivity due to climate model uncertainty and adaptation

Crop production is inherently sensitive to fluctuations in weather and climate and is expected to be impacted by climate change. To understand how this impact may vary across the globe many studies have been conducted to determine the change in yield of several crops to expected changes in climate. Changes in climate are typically derived from a single to no more than a few General Circulation Models (GCMs). This study examines the uncertainty introduced to a crop impact assessment when 14 GCMs are used to determine future climate. The General Large Area Model for annual crops (GLAM) was applied over a global domain to simulate the productivity of soybean and spring wheat under baseline climate conditions and under climate conditions consistent with the 2050s under the A1B SRES emissions scenario as simulated by 14 GCMs. Baseline yield simulations were evaluated against global country-level yield statistics to determine the model's ability to capture observed variability in production. The impact of climate change varied between crops, regions, and by GCM. The spread in yield projections due to GCM varied between no change and a reduction of 50%. Without adaptation yield response was linearly related to the magnitude of local temperature change. Therefore, impacts were greatest for countries at northernmost latitudes where warming is predicted to be greatest. However, these countries also exhibited the greatest potential for adaptation to offset yield losses by shifting the crop growing season to a cooler part of the year and/or switching crop variety to take advantage of an extended growing season. The relative magnitude of impacts as simulated by each GCM was not consistent across countries and between crops. It is important, therefore, for crop impact assessments to fully account for GCM uncertainty in estimating future climates and to be explicit about assumptions regarding adaptation.

A global assessment of the effects of climate policy on the impacts of climate change

This study presents the first global-scale multi-sectoral regional assessment of the magnitude and uncertainty in the impacts of climate change avoided by emissions policies. The analysis suggests that the most stringent emissions policy considered here – which gives a 50% chance of remaining below a 2oC temperature rise target - reduces impacts by 20-65% by 2100 relative to a ‘business-as-usual’ pathway (A1B) which reaches 4oC, and can delay impacts by several decades. Effects vary between sector and region, and there are few noticeable effects of mitigation policy by 2030. The impacts avoided by 2100 are more strongly influenced by the date and level at which emissions peak than the rate of decline of emissions, with an earlier and lower emissions peak avoiding more impacts. The estimated proportion of impacts avoided at the global scale is relatively robust despite uncertainty in the spatial pattern of climate change, but the absolute amount of avoided impacts is considerably more variable and therefore uncertain.

The AVOID programme’s new simulations of the global benefits of stringent climate change mitigation

Quantitative simulations of the global-scale benefits of climate change mitigation are presented, using a harmonised, self-consistent approach based on a single set of climate change scenarios. The approach draws on a synthesis of output from both physically-based and economics-based models, and incorporates uncertainty analyses. Previous studies have projected global and regional climate change and its impacts over the 21st century but have generally focused on analysis of business-as-usual scenarios, with no explicit mitigation policy included. This study finds that both the economics-based and physically-based models indicate that early, stringent mitigation would avoid a large proportion of the impacts of climate change projected for the 2080s. However, it also shows that not all the impacts can now be avoided, so that adaptation would also therefore be needed to avoid some of the potential damage. Delay in mitigation substantially reduces the percentage of impacts that can be avoided, providing strong new quantitative evidence for the need for stringent and prompt global mitigation action on greenhouse gas emissions, combined with effective adaptation, if large, widespread climate change impacts are to be avoided. Energy technology models suggest that such stringent and prompt mitigation action is technologically feasible, although the estimated costs vary depending on the specific modelling approach and assumptions.

The impacts of climate change across the globe: a multi-sectoral assessment

The overall global-scale consequences of climate change are dependent on the distribution of impacts across regions, and there are multiple dimensions to these impacts.This paper presents a global assessment of the potential impacts of climate change across several sectors, using a harmonised set of impacts models forced by the same climate and socio-economic scenarios. Indicators of impact cover the water resources, river and coastal flooding, agriculture, natural environment and built environment sectors. Impacts are assessed under four SRES socio-economic and emissions scenarios, and the effects of uncertainty in the projected pattern of climate change are incorporated by constructing climate scenarios from 21 global climate models. There is considerable uncertainty in projected regional impacts across the climate model scenarios, and coherent assessments of impacts across sectors and regions therefore must be based on each model pattern separately; using ensemble means, for example, reduces variability between sectors and indicators. An example narrative assessment is presented in the paper. Under this narrative approximately 1 billion people would be exposed to increased water resources stress, around 450 million people exposed to increased river flooding, and 1.3 million extra people would be flooded in coastal floods each year. Crop productivity would fall in most regions, and residential energy demands would be reduced in most regions because reduced heating demands would offset higher cooling demands. Most of the global impacts on water stress and flooding would be in Asia, but the proportional impacts in the Middle East North Africa region would be larger. By 2050 there are emerging differences in impact between different emissions and socio-economic scenarios even though the changes in temperature and sea level are similar, and these differences are greater in 2080. However, for all the indicators, the range in projected impacts between different climate models is considerably greater than the range between emissions and socio-economic scenarios.

Remembering Doreen

Remembering Doreen

Migrant mothers: family photographs and the intra-active fashioning of a visual-material ethics

Migrant mothers play crucial roles within the social landscape of schools, particularly in providing care, education and a transition between home and school for their children. My research considers the relevance of theories of space, place, temporality and mobility in Iranian migrant mothers’ production of subjectivity for themselves and their children in and through their family photograph collections. Gillian Rose’s anthropological approach to visual objects is put to use in an exploration of the co-constitution of migrant women and their photographs. In this paper, I trace the shaping of a visual-material ethics within the research context and appropriate to the sensibilities and needs of the participant women who each moved from Iran to Australia with their children. Karen Barad’s notion of a posthumanist ‘ethics of mattering’ is drawn upon in conceptualising a visual-material ethics as fashioned in the intra-actions of people and visual objects. Specific ethical issues considered include the collaborative process of producing a family photograph, and the shaping and reshaping of images from photograph to line drawing to hybridised photograph-line drawing. A research ethics committee’s application of a liberal individualist, utilitarian and positivist biomedical paradigm in considering the research project is discussed as not only inadequate but also incompatible with the fashioning of a visual-material ethics in concert with the participant women and their photographs.

An Iranian migrant mother's production of selves through her family photograph collection

In researching migrant identities, visual methodology offers much promise and yet there is a marked lack of recent research that makes use of visual methods. Previous studies of migrant identities have privileged verbal representations of identities. Gillian Rose's (2010) work with mothers and their family photographs in the United Kingdom, in which she describes the role of family photographs in both producing social subject positions and in maintaining family togetherness across distances, is a useful model for research into the construction and negotiation of migrant identities.

The literature on family photography suggests that it is usually the woman/mother who takes on the role of making the family photograph album; of narrating the family's story (Rose, 2010; Holland, 2009; 1991; Chambers, 2003). The family photograph collection, together with the participant's interwoven verbal interpretation, is a particularly relevant data source for use in identity research as there is the potential for key themes of place, mobilities and space to be explored at new depth and from a feminist perspective.

This paper will report on an ethics approved study of one Iranian migrant mother and her family photograph collection, focusing on her representation of the identities and subjectivities of herself and her children through photographs taken following migration to Australia. The paper will consider the participant's family photographs as both visual objects and visual-verbal narratives produced within historically and culturally situated discourses. It will explore how photographs and oral interpretations cohere to enable migrant mothers to re/produce selves. The paper will examine the production of subject positions specifically in relation to place, mobilities and space.

The research is situated within critical visual ethnography and is informed by a reflexive feminist approach. The meaning making of the photographs under study will be explored at the sites of production, image, and audience. The combined visual-verbal methods used in this study aim to provide a new contribution to the literature on migrant identities and form the basis of a scaled up research design of a larger cohort of mothers.