Environmental Engineering Reference
In-Depth Information
5.6 HEALTH
Increasing temperatures alter the risk of direct and indirect weather-
related impacts on human health, from cardiovascular and respiratory ill-
nesses to infectious diseases (Patz et al., 2005). Quantifying the impact
per degree of global temperature change, however, is complicated by con-
founding factors such as human behavior and socioeconomic conditions
that affect exposure, transmission, and other aspects of risk (Patz et al.,
2005). Here, we discuss three main aspects of health-related risks likely to
be affected by climate change: heat-related illness and death, vector-borne
disease, and health concerns related to poor air and water quality.
Heat-Related Illness and Death
Temperature extremes such as heat waves and periods of extreme cold
are known to produce elevated rates of illness and death (McGeehin and
Mirabelli, 2001). Together, these accounted for 75% of all deaths due to
natural disasters from 1979-2004 (Thacker et al., 2008). From the 1970s
through the 1990s, heat-related mortality in the United States declined due
to acclimatization and increased use of air conditioning, then flattened out
during the past decade (Sheridan et al., 2009).
In the future, extreme heat days and heat wave frequency, intensity, and
duration is projected to increase with global mean temperature, while the
frequency and intensity of winter cold is projected to decrease (Tebaldi et
al., 2006; IPCC, 2007a). Under a 2°C increase in global mean temperature
by end-of-century, for example, the average number of days per year with
maximum temperatures exceeding 38°C or 100°F across much of the south
and central United States is projected to increase by a factor of 3. Under a
3.5°C increase, the number of days is projected to increase by 5 to nearly
10 times historical levels (Figure 5.15).
Although the response of illness and death rates to changing heat ex-
tremes can be modified by acclimatization and adaptation strategies (Ebi et
al., 2004), it is clear that risks of heat-related mortality increase with tem-
perature, while cold-related mortality risks decrease (Gamble et al., 2008).
Prolonged periods of extreme heat with little relief at night can have devas-
tating effects on urban populations (Basu and Samet, 2002), increasing the
risk of both illness and death due to heat stress (Martens, 1998; McGeehin
and Mirabelli, 2001; Schär et al., 2004).
Temperature-related mortality is strongly linked to a wide variety of so-
cial, economic, and behavioral factors, even in industrialized nations such
