9 Human Health Effects 9. Human Health Effects 9.1. Diseases 9.2. Nutrition 9.3. Human Longevity 9.4. Food vs. Nature

The idea that CO2-induced global warming is harmful to people’s health has become entrenched in popular culture, with the reports of the Intergovernmental Panel on Climate Change (IPCC) being the source of much of this concern. In the Working Group II contribution to the Fourth Assessment Report, the authors claim to have “very high confidence” that “climate change currently contributes to the global burden of disease and premature deaths” (IPCC, 2007-II, p. 393). They also claim climate change will “increase malnutrition and consequent disorders ... increase the number of people suffering from death, disease and injury from heatwaves, floods, storms, fires and droughts ... continue to change the range of some infectious disease vectors ... increase the burden of diarrhoeal diseases ... increase cardiorespiratory morbidity and mortality associated with ground-level ozone ... [and] increase the number of people at risk of dengue.” The IPCC admits that warming weather would “bring some benefits to health, including fewer deaths from cold,” but says those benefits “will be outweighed by the negative effects of rising temperatures worldwide, especially in developing countries” (Ibid.). Some of these claims have been shown in previous chapters to be counterfactual. For example, research cited in Chapter 6 showed the global warming that occurred in the twentieth century did not cause more “heatwaves, floods, storms, fires and droughts,” and that a warmer world is likely to see fewer episodes of these extreme weather events than a cooler world. We will not repeat that analysis in this chapter. This chapter reviews data on the relationships between temperature and CO2 and diseases, heatrelated mortality, nutrition, and human longevity. We find in each case that global warming is likely to improve human health. Section 9.4 explains how rising CO2 concentrations in the air will play a positive role in solving the conflict between the need to raise food for a growing population and the need to protect natural ecosystems. Section 9.5 describes the negative role played by increased use of biofuels, which the IPCC advocates in the Working Group III contribution to the Fourth Assessment Report (IPCC, 2007-III), in this same conflict.