These triumphs have their roots in the germ theory of the 1880s, which advocated control of specific infectious agents as opposed to collective sanitation or ecological stability as the itinerary of good health. For example, in Honduras, a fragile ecosystem has rendered the population increasingly vulnerable to changing climate, as reflected in the shifting pattern of insect vectors and infectious diseases ( 4).Įpidemiology has been a major contributing factor to successes in disease control in the past century, highlighted by achievements such as the global eradication of smallpox and the elimination of polio from the Western Hemisphere.
Today, several endangered regions around the globe have been identified where such life support systems as soil fertility and water supplies are threatened ( 82).
During this century, environmentally related calamities, such as drought-induced famines of the Sahel, the spread of the cholera pandemic to Africa and Latin America, and the devastating damage of tropical storms in Bangladesh, highlight the critical ecological balance between humans, climate, infectious agents, and the environment. Throughout history, disasters afflicting human populations, such as floods, famines, and plagues, have been reflections of local ecological disruptions, often the result of adverse weather conditions. Only those species protected from the ravaging waters by Noah's ark survived the flood ( Genesis, chapter 6). The story of Noah reminds us of the awesome capacity of weather to affect human and animal life.
PREVAILING WEATHER IN THE CONTEXT OF GLOBAL ECOSYSTEM CHANGE AND HUMAN HEALTHĬlimate and its effects on many natural processes are fundamental components that allow life to exist on Earth. The field of public health will need to address the potential health risks posed by current and projected hazardous exposures stemming from climate change. As the scale of humankind's impact on biophysical systems rises, the extent of health impacts may grow to affect widely disparate populations. The ecological perspective on population health recognizes that the foundations of good long-term population health depend on the stability and functioning of ecological systems. Human interactions with each other as well as with other living creatures can have important effects on the health of all partners in the complex closed ecosystem of our planet ( 103). During the past 2 decades, population growth and the spread of industrialization, which are unprecedented in human history, have resulted in accumulations of greenhouse gases in the atmosphere that are beginning to affect the world's climate. As we enter the next millennium, it is becoming ever more evident that disturbances of natural ecological systems pose new risks to health. Better understanding of the linkages between climate variability as a determinant of disease will be important, among other key factors, in constructing predictive models to guide public health prevention.Įnvironmental health concerns have traditionally focused on toxicological or infectious risks to human health from local factors. climate or environmentally induced migration or population dislocation. response of vector- and waterborne diseases, and food production and (d) sociodemographic impacts, e.g. atmospheric transport and formation of air pollutants (c) physical/biological consequences, e.g. heat mortality or drowning (b) physical/chemical sequelae, e.g. Health outcomes of climate change can be grouped into those of: (a) direct physical consequences, e.g. The regional impacts of climate change will vary widely depending on existing population vulnerability. Extreme weather variability associated with climate change may especially add an important new stress to developing nations that are already vulnerable as a result of environmental degradation, resource depletion, overpopulation, or location (e.g. This century, the Earth has warmed by about 0.5 degrees centigrade, and the mid-range estimates of future temperature change and sea level rise are 2.0 degrees centigrade and 49 centimeters, respectively, by the year 2100. There are three projected physical consequences of climate change: temperature rise, sea level rise, and extremes in the hydrologic cycle. Projections of future climate change have, therefore, compelled health scientists to re-examine weather/disease relationships. ▪ AbstractMany diseases are influenced by weather conditions or display strong seasonality, suggestive of a possible climatic contribution.