Health and Climate Change: Modelling the Impacts of Global Warming and Ozone Depletion
- Pim Martens
Modelling the effects of environmental health hazards presents scientists with unusual problems. With global climate change it is impossible to rely on empirical data as they are not readily available. In addition, even if non-alarmist projections are true, mankind may not have the time to risk standard prospective research on so potentially deleterious a set of health issues.
Pim Martens has provided a rigorous introduction to the purposes and practices of eco-epidemiology. The objective of this field is to increase competence in projecting the future effects of current trends in order to anticipate the negative effects of global atmospheric change. In developing such projections and estimates, new strategies and techniques are required to manage scientific uncertainty, and this is the focus of the book; the primary technique or tool it explores is simulation modelling. Martens sets out to look at the dynamics underlying the health effects of climate change and ozone depletion, along with their intrinsic uncertainties.
The rationale behind eco-epidemiological modelling is a need to provide a conceptual framework and analytical tools for evaluating situations and phenomena that extend beyond documented experience. Martens considers the development of multidisciplinary, integrated assessment models. His models incorporate projections of global environmental changes and extrapolations of the resulting effects on the health of individuals and populations derived from epidemiological data, biological knowledge, models of societal response, and historical experience. This brief and readable treatment is an introduction to the field and the modelling tools, and provides real-world illustrations of the use of the approach.
Martens begins by providing a succinct summary of the main differences between conventional epidemiological research methods and the systems-based assessment of global atmospheric changes. He then describes the main constructs of eco-epidemiological modelling, before moving quickly through several important areas of environmental threat.
Three potential consequences of global climate change are examined using eco-epidemiological modelling: shifts in the geography of vector-borne infectious diseases (malaria, dengue and schistosomiasis); alterations in exposure to thermal stress within urban populations and consequent thermal-related mortality (for example, cardiovascular and respiratory mortality); and increased incidence of skin cancer associated with increased ultraviolet levels resulting from ozone depletion. The progression of chapters and models builds added sensitivity and complexity into the method. For example, the second model presented on malaria refines the approach by including a simulation of adaptive processes.
Martens concludes with an attempt to translate the results of the methodology into useful information and a discussion of future lines of research.
In general, the book successfully achieves its objectives. One of its strengths is that it incorporates facets not usually covered in methodological reviews, such as a chapter providing estimates of the attributable population burdens of disease or mortality that may result from the global changes analysed. This information helps to make clear the critical link between the adverse effects modelled and their magnitude and specific health impacts.
But, if the book's breadth and effort to appeal to readers of diverse backgrounds and degrees of technical sophistication is a strength, it is also a weakness. The book seems to suffer an identity crisis, being neither introductory or interdisciplinary enough for the generalist, nor conceptually or methodologically deep enough for the expert. Is it a primer for the uninitiated or a case-studies reference for the practitioner? Nevertheless, this drawback is outweighed by a well organized and thoughtful presentation, along with an astute and effective use of graphics and tabular summaries. The book also makes extensive use of reference citations, but the topical index is so abbreviated as to have almost no value.
Martens recognizes the limitations of the models presented, including their immature stage of development, an inability to focus on local outcomes, and a lack of validation. He acknowledges the need for rapid evolution in the methodology, but points out that his case studies demonstrate the feasibility of such efforts to quantify systematically the health impacts of global climate change and ozone depletion. He has provided a solid contribution to an important, underexamined and scientifically complex discipline.