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Andersen, Geary, Portner, and Verner
Besides changes in temperature and precipitation, socioeconomic conditions and human behavior play a major role in spreading waterborne disease. Water storage practices, as well as lack of clean water and sanitation, are important determinants of disease incidence and can themselves be affected by weather extremes. There is evidence that water shortage causes an increase in diarrheal disease due to unsanitary water practices. Lack of access to natural capital assets, such as clean water and basic sanitation, makes the poor more vulnerable to waterborne diseases. For adaptation purposes, it is important to keep in mind that waterborne diseases are driven not only by natural events but also by socioeconomic conditions and human behavior.
Malnutrition The World Health Organization considers malnutrition the single most important risk to global health, making up 15 percent of the total disease burden in DALY (WHO 2003). According to the IPCC, the additional number of people in Latin America at risk of suffering hunger in 2020 will be 5 million under the IPCC’s A2 emission scenario (IPCC 2001a).8 However that projection does not take account of the fertilization effect of the additional carbon dioxide (CO2) in the atmosphere, which will increase yields of some crops. That effect has been estimated to reduce the additional number of people at risk from hunger by 2020 to 1 million (Parry and others 2004). Malnutrition in Latin America and the Caribbean will be affected by droughts as well as by floods, which not only destroy croplands but also cause vector- and waterborne diseases that increase the risk of malnutrition by inhibiting the body’s uptake of nutrients (World Bank 2008). Evidence from drought periods suggests that malnutrition will increase the number of children suffering from stunted growth and irreversibly impaired brain development; indeed young children are the ones most at risk from malnutrition. For them the effects can be lifelong because they are related to development, whereas adults can recover. Malnutrition also raises the risk of mortality from other diseases, especially malaria and diarrhea; it is the main source of mortality from both diseases (Parry and others 2004). Malnutrition in pregnant mothers increases the risk of subsequent infant mortality. More frequent droughts will diminish crop production in some parts of the LAC region, as discussed in chapter 4 (UNDP 2007). In Mexico, crop reductions of 30 percent, the upper end of the range projected by the IPCC by 2020 (IPCC 2007), could threaten livelihoods and food security and be exacerbated by loss of livestock. In northeast