Dear EarthTalk: Has anyone been tracking whether climate change is causing more loss of human life as it gets more pronounced? – Gordon Gould, Compton, Calif.
Researchers think global warming already is responsible for about 150,000 deaths each year and fear that the number may double by 2030, even if we get serious about emissions reductions now.
A team of health and climate scientists from the World Health Organization and the University of Wisconsin at Madison published these findings last year in the science journal Nature. Besides killing people, global warming contributes to about 5 million human illnesses every year, the researchers found. Some of the ways global warming hurts human health include speeding the spread of infectious diseases such as malaria and dengue fever; creating conditions that lead to potentially fatal malnutrition and diarrhea; and increasing the frequency and severity of heat waves, floods and other disasters.
Backing up WHO’s findings is a study by Stanford University civil and environmental engineer Mark Jacobson. It shows a link between rising levels of carbon dioxide in the atmosphere and increased human mortality.
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But global warming skeptics such as atmospheric physicist Fred Singer say cold-weather snaps are responsible for more deaths than warm weather and heat waves. Singer, the founder of the Science and Environmental Policy Project, says that because global warming would raise maximum summer temperatures modestly while raising winter minimum temperatures significantly, it “should help reduce human death rates.”
A team of Harvard researchers found otherwise.
Their July 2007 study, published in the Occupational and Environment Medicine journal, found that global warming is likely to cause more deaths in summer because of higher temperatures, but not fewer deaths in milder winters.
In analyzing weather data related to the deaths of 6.5 million people in 50 U.S. cities between 1989 and 2000, the researchers found that during two-day cold snaps there was a 1.59 percent increase in deaths because of the extreme temperatures. In similar periods of extremely hot weather, mortality rates increased 5.74 percent.
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