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Reprinted with permission of the author, this article appeared in the Fall/Winter 1999 issue of NATIVE AMERICAS, pp. 69-71.

The Tropics Move North
The Prospects Aren't Pretty

Bruce E. Johansen

While I was reviewing John T. Houghton's Global Warming: the Complete Briefing, I was haunted by a conversation my mother had with her sister a few months before. It was springtime. The sister, who has lived in Florida or Georgia most of her life, had just returned from weeding the lawn of her suburban Tallahassee home -- and found her arms covered with poison ivy rash. She had been weeding the same lawn for decades, and it had never before been invaded by poison ivy, Aunt Magel said.
          My aunt was perplexed, but her gardener's senses took her straight to the cause of the infestation: the weather had been hotter and more humid than usual. Her unexpected encounter with an especially noxious weed is one small part of a tapestry of anecdotal evidence indicating that we are already experiencing some of the health effects of living in a warmer (and often more humid) world. Most of these effects are negative. The world of the future will not only be hotter and more humid, but more disease-ridden as well.
          My colleagues in the social sciences tell me (as we stand in air-conditioned hallways) not to get co-relation confused with causation, so my own experiences obviously are not enough to declare a world health emergency in the making, due to global warming. A few statistics, however, may help to build a case for the correlation.
          To check my impressions against a broader array of data, I took a look at the environmental-health news around the world at the time my aunt was surprised by poison ivy in Tallahassee. As my aunt was telling that story, an explosion of termites, mosquitoes and cockroaches hit New Orleans, following an unprecedented five years without frost. As my aunt was nursing her poison ivy, dengue fever spread from Mexico across the border into Texas for the first time since records have been kept. Dengue fever, like malaria, is carried by a mosquito which is limited by temperature. At the same time, Colombia was experiencing plagues of mosquitoes and outbreaks of the diseases they carry, including dengue fever and encephalitis, triggered by a record heat wave followed by heavy rains.
          The global temperature is undeniably rising. According to the National Oceanic and Atmospheric Administration, July of 1998 was the hottest month since reliable worldwide records have been kept, or about 150 years. As this is being written, a glance at the world weather table in the Omaha World-Herald tells me this July may beat it. The year 1998 eclipsed 1997. The previous record-holder had been 1995.
          It's been hot this summer in Moscow, and hot in Beijing and Tokyo, as well as across much of the United States. As I write, the ocean water in the Gulf of Mexico near Tampa has reached 90 degrees. The Weather Service has just announced that New York City's July of 1999 was that city's warmest month on record.
          I am particularly interested in the rising incidence of respiratory diseases and their relationship to a warmer and more humid environment. My wife's older sister Mimi died recently of asthma at age 53. Her husband Paul Marshall recalled that the spring she died was unusually warm and humid, giving rise to an unusual abundance of pollen-producing flowers around their home northeast of Seattle. Since Mimi's death, my wife Pat Keiffer and I have been noting the increasing number of young people who die of this disease.
          According to the American Lung Association, more than 5,600 people died of asthma in the United States during 1995, a 45.3 per cent increase in mortality over ten years, and a 75 per cent increase since 1980. Roughly a third of those cases occurred in children under the age of 18. Shortly after I found these statistics, my eye was drawn to an obituary in the Omaha World-Herald: a local child of 14 had died of asthma, which is now a leading disease among the young. Since 1980, there has been a 160 percent increase in asthma in children under age five.
          Global warming seems to be bringing higher humidities as well as temperatures, and this aggravates health problems, including asthma. Omaha is a particularly interesting case study of increasing humidity, because it lies relatively close to an area, the high plains, where summer heat is usually dry. When I first came to Omaha, during the early 1980s, we seemed to have more dry heat. Some days we got the heat of the desert, and on others we got the heat of the jungle. During the 1990s, dry heat has become a rarity, replaced by higher humidities and higher night-time temperatures. The most obvious indicator of heat -- the afternoon temperature -- hasn't changed as much as the level of misery reflected by the dewpoint. Someone at the National Weather Service should feed summer humidity readings for the last few decades into a computer and see what they get.
          As I wrote this piece, on July 29 in Omaha we had a "global warming special" -- the temperature at 100 was not all that spectacular for this area at mid-summer, but the humidity was 55 per cent and the heat index 119, a record. The dewpoint, at 82, was as high as I can remember in Omaha. The air had the ambiance of the Amazon River valley. At the same time, fellow writer and teacher Barbara Mann e-mailed me from Toledo, Ohio, her home, about "ozone action days" there. These are days on which ozone reaches levels that force people with respiratory ailments (including Barbara, who has asthma) to curtail their activities. She writes of gasping for air in the increasingly humid, ozone-laced heat.
          "What happens to asthmatics in the heat and humidity? Well, we can't breathe. Me, I'm permanently on three different prescription inhalers that I must use at regular intervals, four times a day -- and that's just when I'm well. When I'm sick, there are antibiotics to bust up the hardened mucus in my lungs, along with other regimens of pills to aid the process. When my lungs are irritated (either by pollutants or by natural "triggers" such as pollens) or infected, my air passages swell shut, suffocating me."
          As for the weather changing in Toledo, Mann related, "I haven't made a scientific study. I can only give you my impressions. I remember that my mother told me the week I was born [August 4, 1947] was in the middle of a horrible heat wave. She said it was 120 degrees in the shade, which was the worst anyone could remember. I think that 120 must have been humidity-adjusted. Anyhow, it got that hot once in her memory. In late July, 1999, we spent a week in that range. Last year, and the year before we had a similar heat wave.... I don't ever recall it's having been like this when I was a kid. Our summers were mild, eighties and eminently livable." Mann added that she was raised in the country, and now lives in an urban area, which may account for some of the changes. However, she said, "I think if you look at temperature charts over the past few decades, they will show that temperatures have been consistently and undeniably rising."
          A study by the Sierra Club ["Sierra Club: Global Warming: The High Costs of Inaction."] finds that air pollution which will be enhanced by global warming could be responsible for a number of human health problems, including respiratory diseases such as asthma, bronchitis, and pneumonia. According to Dr. Joel Schwartz, an epidemiologist at Harvard University, current air pollution concentrations are responsible for 70,000 early deaths per year and over 100,000 excess hospitalizations for heart and lung disease in the U.S. This could increase 10 to 20 percent in the U.S. as a result of global warming, with significantly greater increases in countries that are more polluted to begin with, according to Schwartz.
          The study adds that 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 a year in the United States. More than 600 people died of heat exposure in Chicago alone during the summer of 1995. According to Houghton's Global Warming: The Complete Briefing, heat waves can double or triple the overall death rate in large cities. As I write this, the death toll in the United States from our most recent heat wave is nearing 200 people, with Chicago again suffering more deaths than any other city. The elderly and very young again have done most of the suffering.
          Respiratory illness is only part of the picture. The same Sierra Club study indicates that rising heat and humidity will broaden the range of tropical diseases, resulting in "increasing illness and death from diseases such as malaria, cholera, and dengue fever, whose range will spread as mosquitoes and other disease vectors migrate."
          The Sierra Club study says that 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. Since 1981, the number of cases of dengue fever has risen significantly in South America and has begun to spread into the United States. According to health experts quoted by the Sierra Club study, "The current outbreak [of dengue], with its proximity to Texas, is at least a reminder of the risks that a warming climate might pose."
          The Sierra Club study concludes: "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 supported the Sierra Club's conclusions as he stated that "If tropical weather is expanding it means that tropical diseases will expand. We're seeing malaria in Houston, Texas." Italy had an outbreak of malaria in 1997, according to The Guardian, of London, England.
          In many regions of the world, malaria is already resistant to the least expensive, most widely distributed drugs. The increased incidence of diseases also will add to society's expenditures for hospitalization and other health care, the cost of lost productivity, and the trauma of illness and death, according to the Sierra Club. The United States spent $751.8 billion in 1991 on health care. Worldwide, according to Houghton, malaria already causes two million deaths a year, as well as 350 million new infections. The mosquitoes which spread the disease require both heat and humidity.
          The level of humidity required for malaria-carrying mosquitoes to survive is roughly 50 per cent. It is perhaps notable, in my neighborhood, that days drier than that have been notably absent in Omaha the past few summers. One wonders how far a malarial mosquito can fly. We can always hope for an early freeze.

Bruce E. Johansen, Robert T. Reilly Professor of Communication and Native American Studies at the University of Nebraska at Omaha, is author of Debating Democracy: The Iroquois Legacy of Freedom.

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