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Abstract: In this paper, control theory is used to study the connection between human activities and global warming. A feedback model is proposed and tested against temperature and carbon dioxide concentration historical data. Four scenarios are taken into account and simulated by the model; stability analysis is also discussed. The model proposed here simulates the historical data correctly and the scenarios show that, even in the case of dramatic reduction of the anthropogenic carbon dioxide emission, the temperature will not decrease for a certain time. Stability analysis reveals a complex pole near the unit circle. This means that, although the system at the moment is stable, it is very close to becoming unstable with unpredictable consequences on climate change. [Copyright &y& Elsevier]

The term ‘vulnerability’ is used in many different ways by various scholarly communities. The resulting disagreement about the appropriate definition of vulnerability is a frequent cause for misunderstanding in interdisciplinary research on climate change and a challenge for attempts to develop formal models of vulnerability. Earlier attempts at reconciling the various conceptualizations of vulnerability were, at best, partly successful. This paper presents a generally applicable conceptual framework of vulnerability that combines a nomenclature of vulnerable situations and a terminology of vulnerability concepts based on the distinction of four fundamental groups of vulnerability factors. This conceptual framework is applied to characterize the vulnerability concepts employed by the main schools of vulnerability research and to review earlier attempts at classifying vulnerability concepts. None of these one-dimensional classification schemes reflects the diversity of vulnerability concepts identified in this review. The wide range of policy responses available to address the risks from global climate change suggests that climate impact, vulnerability, and adaptation assessments will continue to apply a variety of vulnerability concepts. The framework presented here provides the much-needed conceptual clarity and facilitates bridging the various approaches to researching vulnerability to climate change. [Copyright &y& Elsevier]