The Impacts of Global Warming
While precisely when and where the effects of global warming will occur is uncertain, each of us will face the impacts in one
way or another. Some of the impacts are:
Increasing illness and death from diseases such as malaria, cholera, and dengue fever, whose range will spread as
mosquitoes and other disease vectors migrate.
Rising sea levels resulting from warming oceans and melting glaciers, causing massive flooding in coastal areas, where
over half of the U.S. population lives and which provide significant revenues and jobs.
Greater extremes in temperatures and precipitation, which will create greater variability in agricultural production. These
swings will disrupt markets for food and other agricultural commodities with potentially devastating consequences.
Warming waters and changing water flows, which will place numerous fish species at risk, affecting both commercial
and recreational fishermen, the availability of food on the market, and the ecosystems in which the fish play an important
role.
This section highlights these and other potential effects of global warming on numerous sectors of society based on existing
literature on the subject. We identify effects on human health; coastal communities; agriculture; forests; hurricanes; the
insurance industry; population migration; species and ecosystems; water resources and fisheries; energy demand and supply;
air quality; and infrastructure investment. The information presented here is by no means comprehensive. But it illustrates the
degree to which quantitative cost-benefit studies fail to include the full costs of global warming.
Health Impacts: Increased Illness and Death from Tropical Diseases and Heat Waves
Changes in climate due to global warming are expected to have a major impact on human health. More extreme temperatures
and precipitation and greater frequency and severity of storms, floods, and droughts will likely lead to increased deaths,
illnesses and injuries.
Global warming will directly kill hundreds of Americans from exposure to extreme heat during summer months. The U.S.
Centers for Disease Control and Prevention have found that extreme heat is currently responsible for an average of at least
240 deaths annually in the United States (Colburn, July 18, 1995). Yet, according to Anthony J. McMichael, Professor of
Epidemiology at the London School of Hygiene and Tropical Medicine, that higher summer temperatures in both temperate
and tropical countries could increase the rates of serious illness and death from heat-related causes by as much as six times the
current level, with the greatest impact falling on the sick and elderly (McMichael, 1993, p. 143).
The record heat wave in July of 1995 killed at least 669 people in the U.S., exemplifying the risk that extreme heat places on
human mortality (Star-Ledger Wire Services, July 19, 1995). Increased illness and deaths as a result of the heat could cost
society billions of dollars in health care expenditures, diminished worker productivity, and increased use of air conditioning —
not to mention the social costs associated with pain and suffering and the loss of loved ones.
Global warming will also expand the ranges of many infectious diseases, including malaria, dengue fever, and cholera, as the
vectors that carry such diseases expand their ranges in a warmer world and as human populations migrate. The World Health
Organization projects tens of millions more cases of malaria and other infectious diseases (Stone, February 17, 1995). The
Dutch health ministry predicts that more than a million people may die annually as a result of the impact of global warming on
malaria transmission in North America and Northern Europe (Epstein, February 3, 1995, p. 7).
The effects of the recent El Niño provide an indication of how sensitive diseases can be to changes in climate. According to a
recent Harvard University study, warming waters in the Pacific Ocean likely contributed to the severe outbreak of cholera that
led to thousands of deaths in Latin American countries (Allen, March 6, 1995). And since 1981, the number of cases of
dengue fever has risen significantly in South America and has begun to spread into the U.S. (See Figure 1). According to
health experts, "The current outbreak [of dengue], with its proximity to Texas, is at least a reminder of the risks that a warming
climate might pose." (Dawson, October 24, 1995).
Another striking example of how climate can affect disease is the deadly 1993 outbreak of hantavirus pulmonary syndrome in
the Southwestern U.S. A six year drought killed off most predators of the rodents that carry the hantavirus. Without
interference from predators, rodent populations swelled. The population ballooned further as an extraordinary wet season
ended the drought and caused the rodents' food supply to grow, bringing the rodents — and the virus — into contact with
humans (Morse, September 11-12, 1995).
While it is difficult to prove that any particular outbreak was caused or exacerbated by global warming, such incidents provide
a hint of what might occur as global warming escalates. Dr. Paul Epstein on the Harvard School of Public Health and a
member of the IPCC has concluded that this hantavirus outbreak and other recent disease outbreaks are a harbinger of things
to come. Dr. Epstein states that "If tropical weather is expanding it means that tropical diseases will expand. We're seeing
malaria in Houston, Texas" (Allen, March 6, 1995).
Treatments for some of these diseases exist, but at a cost. The global market for antimalarial drugs, for example, is estimated at
over $100 million (Foster, June 1994). And over time, research into new drugs will be necessary if warmer temperatures
enable parasites to evolve greater resistance to pesticides and medicine (McMichael, 1993, p. 158). In many regions of the
world, malaria is already resistant to the least expensive, most widely distributed drugs (Foster, June 1994). The increased
incidence of diseases will also add to society's expenditures for hospitalization and other health care, the cost of lost
productivity, and the trauma of illness and death. The U.S. spent $751.8 billion in 1991 on health care (according to SAUS
1994, Table 148). Even a 0.5 percent increase in health care expenditures as a result of global warming would impose
additional annual costs of over $3.8 billion (Cline, 1992, p.118). In addition, epidemics create numerous secondary costs,
including losses in tourism, business travel, and international trade. For example, the 1994 outbreak of plague in India cost $2
billion in lost revenues to hotels, airlines, and other businesses (Epstein, September 11-12, 1995).
Well beyond these dollar costs are the incalculable losses in human lives and the enormous suffering that health problems such
as physical injuries, starvation, and tropical diseases can bring. |
