Environmental Engineering Reference
In-Depth Information
BOX 5.4 HEAT-RELATED MORTALITY IN CHICAGO
The Chicago heat wave of 1995 is estimated to have been responsible for 692 heat-related
deaths within the city of Chicago itself (Kaiser et al., 2007). As global mean temperatures in-
crease, 1995-like conditions are projected to become more frequent in Chicago. Under a 2°C
change in global mean temperature, annual average mortality rates are projected to equal those
of 1995. Under a 4°C change in global mean temperature, annual average mortality is projected
to be twice 1995 levels, with 1995-like heat waves occurring as frequently as three times per
year (Hayhoe et al., 2010).
as the United States (e.g., Basu, 2009; Ekamper et al., 2009). Since observed
mortality rates are more responsive to changes in high temperature than low
temperature extremes, at the global scale an overall increase in heat-related
deaths is expected to exceed the projected decrease in cold-related deaths
(Medina-Roman and Schwartz, 2007).
Several recent severe heat waves have focused public attention on the
health risks associated with extreme heat, including a 1995 heat wave in
Chicago (see Box 5.4) and the unprecedented European heat wave of 2003,
estimated to be responsible for approximately 70,000 excess deaths across
16 European countries (Robine et al., 2008). Past events such as these can
be used as case studies for evaluating the potential impacts of future climate
conditions. For example, observations of the health effects of a heat wave
in California in July 2006 showed that heat-related mortality increased 9%
for every 5.5°C increase in apparent temperature, with that specific event
causing an estimated 160-505 deaths, a 6-fold increase in the number of
heat-related visits to the emergency room, and 10-fold increase in heat-
related hospitalizations (Knowlton et al., 2009; Ostro et al., 2009).
Using an analogue approach, Kalkstein et al. (2008) estimated the num-
ber of heat-related deaths that might occur in U.S. cities if they experienced
conditions similar to the severe Paris heat wave of 2003. Compared to the
hottest summers on record, heat-related deaths in St. Louis and New York are
projected to increase by 29% and 155%, respectively. Other cities, including
Washington, Philadelphia, and Detroit, could experience 2-11% more heat-
related deaths, compared to their hottest summers on record. This range of
response illustrates the variation among cities in their sensitivity to extreme
heat, which might result from factors such as baseline climate conditions
(cooler cities may be more susceptible to heat), demographic patterns, and
acclimatization measures such as air conditioning.
Heat watch-warning systems presently in operation in major U.S.,
