2.4 Public health and sustainability  (Page 3/12)

Residents of sprawling counties were likely to walk less during leisure time, weigh more, and have greater prevalence of hypertension than residents of compact counties ( Ewing, Schmid, Killingsworth, Zlot,&Raudenbush , 2003 ).

While more compact development is found to have a negative impact on weight, we also find that individuals with low BMI are more likely to select locations with dense development. This suggests that efforts to curb sprawl, and thereby make communities more exercise-friendly, may simply attract those individuals who are predisposed to physical activity ( Plantinga& Bernell, 2007 ).

Impacts of climate change

Public health studies have been conducted with regard to many of the predicted environmental effects of climate change. Thus, it is somewhat easier to examine the public health implications of this outcome of unsustainable behavior. Figure How Climate Change Affects Population describes the pathways by which climate change affects public health. To the left we see the natural and anthropogenic, or human-caused activities that affect climate change, which result in climatic conditions and variability; if we can mitigate those events we can reduce climate change. These activities first result in environmental impacts such as severe weather events, disturbed ecosystems, sea-level rise, and overall environmental degradation. Those impacts can then result in a broad range of health effects that we can adapt to, to a certain extent. These impacts are generally categorized into three areas: heat induced morbidity and mortality, infectious diseases, and impacts due to the effect of extreme weather such as flooding and drought on the social welfare of the population.

Measurement of health effects from climate change can only be very approximate. One major study, by the World Health Organization (WHO), was a quantitative assessment of some of the possible health impacts that looked at the effects of the climate changes since the mid-1970s and determined that this may have resulted in over 150,000 deaths in 2000. The study concluded that the effects will probably grow in the future ( World Health Organization, 2009 ).

Extreme weather

Climate change can influence heat-related morbidity    and mortality    , generally a result of the difference between temperature extremes and mean climate in a given area. Higher temperatures in the summer increase mortality. Studies on the effects of heat waves in Europe indicate that half of the excess heat during the European heat wave of 2003 was due to global warming and, by inference, about half of the excess deaths during that heat wave could be attributed to human-generated greenhouse gas emissions (see Haines, Kovats, Campbell-Lendrum,&Corvalan, 2006 ; Hellmann, Lesht,&Nadelhoffer, 2007 ; McMichael, 2006 ). Urban centers are more susceptible due to the urban heat island effect that produces higher temperatures in urban areas as compared to the near-by suburbs and rural areas. Lack of vegetation or evaporation, and large areas of pavement, in cities result in an “Urban Heat Island,” where urban areas are warmer than the neighboring suburban and rural areas (See Figure Sketch of an Urban Heat-Island Profile ). Adaptation can help reduce mortality through greater prevention awareness and by providing more air-conditioning and cooling centers.