Thomas E. Downing

Climate change and social vulnerability: Toward a sociology and geography of food insecurity

Abstract Coping with climatic variations or future climate change must be rooted in a full understanding of the complex structures and causes of present vulnerability, and how it may evolve over the coming decades. A theory of the social vulnerability of food insecurity draws upon explanations in human ecology, expanded entitlements and political economy to map the risk of exposure to harmful perturbations, ability to cope with crises, and potential for recovery. Vulnerable socio-economic groups in Zimbabwe and the potential effects of climate change illustrate some of the applications of the theory.

Adapting to climate change in Africa

The intersection of present vulnerability and the prospect of climate change in Africa warrants proactive action now to reduce the risk of large-scale, adverse impacts. The process of planning adaptive strategies requires a systematic evaluation of priorities and constraints, and the involvement of stakeholders. An overview of climate change in Africa and case studies of impacts for agriculture and water underlie discussion of a typology of adaptive responses that may be most effective for different stakeholders. The most effective strategies are likely to be to reduce present vulnerability and to enhance a broad spectrum of capacity in responding to environmental, resource and economic perturbations. In some cases, such as design of water systems, an added risk factor should be considered.

Societal Vulnerability to Climate Change and Variability

Institutions in many wealthy industrialised countries are robust and their societies appear to be relatively well insulated against the impacts of climate variability, economic problems elsewhere and so on. However, many countries are not in this position, and there is a growing group of humanity which is not benefiting from the apparent global adaptive trends. Worst case scenarios reinforce the impact of this uneven distribution of adaptive capacity, both between and within countries. Nevertheless, at the broad global scale human societies are strongly adaptive and not threatened by climate change for many decades. At the local level the picture is quite different and the survival of some populations at their present locations is in doubt. In the absence of abatement, the longer term outlook is highly uncertain. Adaptation research needs to begin with an understanding of social and economic vulnerability. It requires a different approach to the traditional IPCC impacts assessment, as human behaviour, institutional capacity and culture are more important than biophysical impacts. This is consistent with the intellectual history of the IPCC which has gradually embraced an increasing range of disciplines.

Vulnerability to hunger in Africa: A climate change perspective☆

Abstract Limitations of present assessments of climate change impacts on food supplies are addressed, and a new approach is proposed. This uses the concept of vulnerability to hunger as a point of departure. A typology of vulnerability indices is developed and several measures of vulnerability are explored using information from case studies reported in the literature and research coordinated by the authors research group. An initial synthesis of data about climate change and vulnerability to hunger is illustrated for Africa.

Getting the scale right: a comparison of analytical methods for vulnerability assessment and household-level targeting.

This paper introduces broad concepts of vulnerability, food security and famine. It argues that the concepts and theories driving development and implementation of vulnerability assessment tools are related to their utility. The review concludes that socio-geographic scale is a key issue, and challenge. It analyses three vulnerability assessment (VA) methods, using Ethiopia as a case study. Facing the challenges of vulnerability assessment and early warning requires providing accurate information at the required scale, useful for multiple decision-makers within realistic institutional capacities.

Agent-based integrated assessment modelling: the example of climate change

Current approaches to deal with the socio-economic implications of climate change rely heavily on economic models that compare costs and benefits of different measures. We show that the theoretical foundations underpinning current approaches to economic modelling of climate change are inappropriate for the type of questions that are being asked. We argue therefore that another tradition of modelling, social simulation, is more appropriate in dealing with the complex environmental problems we face today.

Understanding climate policy using participatory agent-based social simulation

Integrated assessment models (IAMs) have been widely applied to questions of climate change policy--such as the effects of abating greenhouse gas emissions, balancing impacts, adaptation and mitigation costs, understanding processes of adaptation, and evaluating the potential for technological solutions. In almost all cases, the social dimensions of climate policy are poorly represented. Econometric models look for efficient optimal solutions. Decision making perspectives might reflect broadscale cultural theory, but not the diversity of cognitive models in practice. Technological change is often ignored or exogenous, and without understanding of stakeholder strategies for innovation and diffusion. Policy measures are proposed from idealised perspectives, with little understanding of the constraints of individual decision makers. We suggest a set of criteria for IAMs that can be used to evaluate the choice and structure of models with respect to their suitability for understanding key climate change debates. The criteria are discussed for three classes of models-- optimising econometric models, dynamic simulation models and a proposed agent-based strategy. A prototype agent-based IAM is reported to demonstrate the usefulness and power of the agent based approach and to indicate concretely how that approach meets the criteria for good IAMs and to complex social issues more generally.

Scaling-up the AFRCWHEAT2 model to assess phenological development for wheat in Europe

Abstract A method was developed for scaling-up the AFRCWHEAT2 model of phenological development from the site to the continental scale. Four issues were addressed in this methodology: (i) the estimation of daily climatic data from monthly values, (ii) the estimation of spatially variable sowing dates, (iii) the simulation of multiple cultivars, and (iv) the validation of broad-scale models. Three methods for estimating daily minimum and maximum temperatures from monthly values were compared using AFRCWHEAT2: a sine curve interpolation, a sine curve interpolation with random daily variability, and two stochastic weather generators (WGEN and LARS-WG). The sine curve interpolation was selected for the continental scale application of AFRCWHEAT2 because computational time was short and errors were acceptably small. The average root mean square errors (RMSEs) for the dates of double ridges, anthesis and maturity were 6.4, 2.2 and 2.1 days, respectively. The spatial variability of European sowing dates was reproduced using a simple climatic criterion derived from the AFRCWHEAT2 vernalization curve. The use of several cultivar calibrations enabled the broad-scale model to capture current responses and compare responses to future climate change. Results from the continental scale model were validated using a geographically-referenced database of observed phenological dates, output from other site-based models and sensitivity analysis. The spatial model was able to emulate a similar spatial and temporal variability in phenological dates to these sources under the present climate. The predominant effect of an increase in mean temperature was a reduction in the emergence to double ridges phase. The shift in the timing of subsequent development stages to earlier in the season meant that changes in their duration were relatively minor. Changes in inter-annual temperature variability resulted in only small changes in the mean date of development stages, but their standard deviation altered significantly.

Seasonal forecasting for climate hazards: Prospects and responses

One of the most promising developments for early warning of climate hazards is seasonal climate forecasting. Already forecasts are operational in many parts of the tropics and sub-tropics, particularly for droughts and floods associated with ENSO events. Prospects for further development of seasonal forecasting for a range of climatichazards are reviewed, illustrated with case studies in Africa, Australia, the U.S.A. and Europe. A critical evaluation of the utility of seasonal forecasts centres on vulnerability, communicationchannels, and effective responses. In contrast to short-term prediction, seasonal forecasts raise new issues of preparedness and the use of information.

Climate Change and Food Insecurity: Toward a Sociology and Geography of Vulnerability

Global climate change presents a serious challenge to future livelihood strategies of third world peoples, especially for those social groups which are currently poor and vulnerable. Relatively modest adverse changes in community resource availability and/or economic output imply critical shifts in food security. Feasible strategies for coping with future climate change must be rooted in a full understanding of the complex structure and causes of presentday social vulnerability. In the case of global warming and its human implications, sophisticated models forecasting climate change and impacts, in our view, must begin with a compelling theory of contemporary vulnerability to hunger and famine.