Chapter 9 challenges the IPCC’s claim that CO2-induced global warming is harmful to human health. The IPCC blames high-temperature events for increasing the number of cardiovascular-related deaths, enhancing respiratory problems, and fueling a more rapid and widespread distribution of deadly infectious diseases, such as malaria, dengue and yellow fever. However, a thorough examination of the peer-reviewed scientific literature reveals that further global warming would likely do just the opposite and actually reduce the number of lives lost to extreme thermal conditions. We also explain how CO2-induced global warming would help feed a growing global population without major encroachment on natural ecosystems, and how increasing production of biofuels (a strategy recommended by the IPCC) damages the environment and raises the price of food.

Chapter 9 Key Findings

• The IPCC alleges that “climate change currently contributes to the global burden of disease and premature deaths” and will “increase malnutrition and consequent disorders.” In fact, the overwhelming weight of evidence shows that higher temperatures and rising CO2 levels have played an indispensible role in making it possible to feed a growing global population without encroaching on natural ecosystems.

• Global warming reduces the incidence of cardiovascular disease related to low temperatures and wintry weather by a much greater degree than it increases the incidence of cardiovascular disease associated with high temperatures and summer heat waves.

• Mortality due to respiratory diseases decrease as temperatures rise and as temperature variability declines.

• Claims that malaria and tick-borne diseases are spreading or will spread across the globe as a result of CO2-induced warming are not supported in the scientific literature.

• Total heat-related mortality rates have been shown to be lower in warmer climates and to be unaffected by rising temperatures during the twentieth century.

• The historical increase in the air’s CO2 content has improved human nutrition by raising crop yields during the past 150 years on the order of 70 percent for wheat, 28 percent for cereals, 33 percent for fruits and melons, 62 percent for legumes, 67 percent for root and tuber crops, and 51 percent for vegetables.

• The quality of plant food in the CO2-enriched world of the future, in terms of its protein and antioxidant (vitamin) contents, will be no lower and probably will be higher than in the past.

• There is evidence that some medicinal substances in plants will be present in significantly greater concentrations, and certainly in greater absolute amounts, than they are currently.

• The historical increase of the air’s CO2 content has probably helped lengthen human lifespans since the advent of the Industrial Revolution, and its continued upward trend will likely provide more of the same benefit.

• Higher levels of CO2 in the air help to advance all three parts of a strategy to resolve the tension between the need to feed a growing population and the desire to preserve natural ecosystems: increasing crop yield per unit of land area, increasing crop yield per unit of nutrients applied, and increasing crop yield per unit of water used.

• Biofuels for transportation (chiefly ethanol, biodiesel, and methanol) are being used in growing quantities in the belief that they provide environmental benefits. In fact, those benefits are very dubious. By some measures, “the net effect of biofuels production ... is to increase CO2 emissions for decades or centuries relative to the emissions caused by fossil fuel use.”

• Biofuels compete with livestock growers and food processors for corn, soybeans, and other feedstocks, leading to higher food prices. Rising food prices in 2008 led to food riots in several developing countries. The production of biofuels also consumes enormous quantities of water compared with the production of gasoline.

• There can be little doubt that ethanol mandates and subsidies have made both food and energy more, not less, expensive and therefore less available to a growing population. The extensive damage to natural ecosystems already caused by this poor policy decision, and the much greater destruction yet to come, are a high price to pay for refusing to understand and utilize the true science of climate change.

Chapter 9: Human Health Effects (PDF, 322 kb)

     9.1. Diseases (PDF, 105 kb)
            9.1.1. Cardiovascular Diseases
            9.1.2. Respiratory Diseases
            9.1.3. Malaria
            9.1.4. Tick-Borne Diseases
            9.1.5. Heat-Related Morbidity

     9.2. Nutrition (PDF, 148 kb)
            9.2.1. Food Quantity
            9.2.2. Food Quality
            9.2.3. Medicinal Constituents

     9.3. Human Longevity (PDF, 63 kb)

     9.4. Food vs. Nature (PDF, 76 kb)

     9.5. Biofuels (PDF, 72 kb)
            9.5.1. About Biofuels
            9.5.2. Costs and Benefits
            9.5.3. Net Emissions
            9.5.4. Impact on Food Prices
            9.5.5. Use of Water
            9.5.6. Conclusion