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Title: The role of climate science in understanding climate security
Author: Lewis, K.
Awarding Body: University of Exeter
Current Institution: University of Exeter
Date of Award: 2019
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Climate change is widely recognised to represent a threat to human security, but understanding how this threat may manifest itself is a non-trivial task. Climate Security spans natural and social science boundaries, where differences in analytical methods, language and scale between disciplines can result in barriers to accessing climate science knowledge. This thesis attempts to address some of these knowledge problems and demonstrate the potential to improve the integration and utilisation of climate science in understanding climate and security. Using a systems-based approach, the example of long term food insecurity in Ethiopia is explored. Despite large increases in national cereal production in recent decades, Ethiopia continues to experience regular acute food insecurity crises, often associated with drought events. However, the meteorology of these events is poorly defined and local populations frequently experience food insecurity crises in years when national rainfall and cereal production totals are high. The on-going recurrence of acute food insecurity is a feature of the heterogeneity of climate and climate variability in Ethiopia, but only in the context of a food system dominated by smallholder farming and climate-sensitive livelihoods. Over climate change timescales both the climate and the food system will be subject to change, and so information on climate change needs to be provided in the context of food system changes. To explore the potential for climate change to threaten longer term food security, a simple 'toy' model of the food system in Ethiopia was developed. The model was run with a number of climate model projections and under different scenarios of transformational change to the food system. The results showed that climate change will have a negative impact on achieving food security in Ethiopia, but that the scale of this impact is smaller than potential positive food system changes. However, climate change does substantially off-set much of the modelled improvement associated with system interventions, and without ambitious system changes the food security situation in Ethiopia will become more challenging. In addition, the model shows an increase in food system variability associated with increased climate variability, which is amplified by the multiplicative effect of the food system changes. This suggests that substantial policy interventions are required if Ethiopia is to meet its food security needs long term, and that incremental adaptation to improve resilience to climate variability is required alongside transformational system change. The simple food system model was then run over Botswana, Tanzania and Mali for comparison. For Tanzania and Mali the scale of positive system changes was again larger than the negative climate change impacts, but as in Ethiopia climate change both exacerbated system variability and made transformational change necessary. In Botswana, where there is a strong signal for drying and the potential for transformational system change is more limited, the long term food security outlook under climate change is less optimistic. The simple systems model approach shows the potential for climate model projections to be better utilised in evaluating the scale and direction of the climate security threat, and that a systems approach can facilitate trans-disciplinary research in Climate Security aimed at policy-relevance.
Supervisor: Lenton, T. ; Buontempo, C. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Climate change ; Security ; Food security ; Systems