Health and Climate Change: Modelling the Impacts of Global Warming and Ozone Depletion

THIS BOOK DISCUSSES the potential health consequences of global change: shifts in the geography of vector-borne infectious diseases due to the anticipated changes in regional climatic conditions; alterations in exposure to thermal stress in urban populations under conditions of climate change; and increases in the incidence of skin cancer in selected populations in response to continuing losses of stratospheric ozone. The book provides a foundation for thinking about how best to tackle a varied spectrum of human health hazards posed by different aspects and combinations of global change processes. The study is based on eco-epidemiological modelling, which consists of computer simulation models dealing with the effects of climate change on vector-borne diseases and thermal-related mortality, and the effects of ozone depletion on skin cancer incidence. An important objective of the work is to provide a better understanding of the dynamics underlying the health impacts of climate change and ozone depletion, and the sensitivities and uncertainties surrounding these impact estimates.

The book begins its discussion by outlining the main differences between conventional epidemiology and an eco-epidemiological modelling analysis. The modelling systems and computer programmes utilized in the study are discussed, and some key issues in the development of integrated mathematical models in the health impact assessment of climate change and ozone depletion are reviewed.

Striking amongst the book's findings is the forecast of an increase from around 60 per cent to 70 per cent in the proportion of the population in Africa, Asia and Latin America living within the potential malaria transmission zone by the middle of the next century. Moreover, all of the predicted climatic scenarios were found to increase the populations at risk of malaria, schistosomiasis and dengue, with the additional number of people at risk estimated to reach 720 million, 40 million and 195 million, respectively. The study then uses a malaria assessment model intended to include evolutionary processes of resistance development of the parasite, in order to provide insights into this complex adaptive system and thus contribute to a better understanding of the possible effects of control programmes. The model suggests that that in highly endemic regions, the use of insecticides and drugs may lead to an increase in incidence due to enhanced resistance development. Conversely, projected climate change may lead to a limited reduction in the occurrence of malaria due to the presence of a higher percentage of immune persons in the older age class. Thus, socio-economic development such as the provision of vector-proof housing, combined with selective dosages of drugs and insecticides is advocated.

The final sections analyze the potential effects that climate change will have on mortality rates due to thermal stress, and the impact of ozone depletion on the incidence of skin cancer. Although the study recognizes that more research is needed, it concludes that global warming may cause a decrease in mortality rates, especially of cardiovascular diseases. Conclusions surrounding an increase in skin cancer incidence is difficult to predict, as personal habits, ozone depletion, and ageing of the population all contribute to skin-related illnesses.