Turning up the Heat: Global Warming & Human Health

Turning up the Heat: Global Warming & Human Health


By Carl Bloice and Conn Hallinan

On July 21, farmworker Constantino Cruz put in a nine-hour day. It was the third week of 100 degree plus weather in Shafter, a town in California’s fertile Central Valley. At the end of his shift the 24-year old fieldworker collapsed. He died 10 days later. Record heat killed three other farmworkers that same month.

Ninety-degree water temperatures in the Gulf of Mexico transformed Hurricane Katrina from a troublesome storm to a city killer. July is early in the season for a hurricane, and Katrina was not the first. Hurricane Dennis, the earliest recorded hurricane in history, had already pummeled Florida.

Public health officials in Colombia are worried because malaria-carrying mosquitoes, normally restricted to the wet lowlands, are appearing well above 5,000 feet. Researchers have also noticed an increase of ticks bearing Lyme disease in coastal areas of Massachusetts and Scandinavia.

Asthma has shown a worrisome jump worldwide, with a disturbing trend toward increased lethality. U.S. asthma death rates have risen from 8.2 per 100,000 in 1979 to 18 per 100,000 in 1995, with the heaviest burden, according to the National Institute of Allergy and Infectious Diseases, falling on “poor, inner-city African Americans.”

Heat waves, violent weather, and disease epidemics sound almost Biblical, but a broad consensus of scientists says all this has less to do with the sacred than the profane: human activity is heating the world at a dramatic pace, and the health care issues of a substantially warmer world are profound.

There are a handful of scientists who still resist the idea of global warming, but they constitute, “maybe a half a dozen in the world,” according to Susanne Moser. “Ninety-nine point nine percent of scientists are convinced global warming is underway.”

Moser is with the National Center for Atmospheric Research in Boulder, Co. and one of the authors of “Rising Heat and Risks to Human Health,” a Union of Concerned Scientists’ (UCS) study of the potential impact of climate change on the state of California.

According to the United Nation’s Intergovernmental Panel on Climate Change (IPCC), global warming “is projected to increase threats to human health, particularly among lower-income populations, predominantly within tropical/subtropical countries.”

Tracking the health implications of climate change is a little like that old spiritual: “The knee bone’s connected to the thigh bone, the thigh bone’s connected to the hip bone…” It is enormously complex, intricately inter-related, and embraces a staggeringly wide number of phenomena. It is also subtle, which makes getting people to take notice difficult.

“Climate change is big,” says Moser, “but you can’t see global warming in the same sense that you can see a dirty stream.”

Experts generally break down the health implications of global warming into three broad categories: heat, disease, and extreme weather events, like floods, droughts, and storms. While all are different, there is a nexus between them that sometimes comes out looking like some enormous environmental rubix cube.

Heat is a case in point. The heat that killed four farmworkers this past July was hardly the first heat wave to strike California, but if UCS’s predictions are accurate, such heat waves will be higher and far more frequent in the future.

According to a study of the effects of climate change on health by Laurence Kalkstein and Kathleen Valimont of the Environmental Protection Agency’s (EPA) Science and Advisory Committee, temperature studies dating back to the early 1960s demonstrate there is a link between heat and such health problems as heart failure, cerebrovascular complications, peptic ulcers, glaucoma, goiter and eczema.

The heat wave that enveloped Europe in the summer of 2003 killed over 35,000 people, 15,000 in France alone, an event that Pulitzer Prize-winning investigative journalist and author Ross Gelbspan says had global warming written all over it. “That heat wave had a very specific signature of human induced heating.”

Gelbspan has worked for the Washington Post, Philadelphia Bulletin, and Boston Globe, and is author of two books, The Heat is On, and Boiling Point.

One of the characteristics of global warming is the buildup of carbon dioxide (CO2), one of the so-called “greenhouse gases.” Increasing CO2 levels, says Gelbspan, causes “night time temperature levels to rise, so that there is no cooling off period when the sun goes down. It means there is no recuperation time for people caught in it.”

CO2 has risen from 280 parts per million in the 18th century, to 375 parts per million today. The gas is very stable, lasting upwards of 100 years.

According to the UCS study, while the greatest temperature rises will be in the California’s Central Valley, it is coastal cities like San Francisco that are predicted to have the highest mortality. Residents in San Francisco, says the report, are unaccustomed to hot weather and housing is not designed to moderate its effects.

That mortality will largely fall, according to an EPA study of past U.S. heat waves, on “poor inner-city residents who have little access to cooler environments.” Indeed, the overwhelming majority of those who died in the European heat wave were old and poor.

The UCS report urges “significant efforts” to provide early warning systems–most states do not have any ability to predict heat waves–cooling centers, education and community support systems.

But for cash-strapped public health officials trying to hold the gates against HIV and antibiotic-resistant tuberculosis, killer heat waves and disease-bearing mosquitoes are a bit of an abstraction.

“It’s a matter of priorities,” says Contra Costa Public Health Director, Dr. Wendell Brunner. He points to West Nile fever as an example. While he is all for getting rid of mosquitoes, he says the County is spending more on mosquito abatement than on HIV. “We have one case of West Nile, we have thousands infected with HIV, almost all of whom will die.”

San Francisco, according to Dr. Rajiv Bhatia, Director of Occupational and Environmental Health for the city’s Public Health Department, has chosen to focus on long range solutions rather than short range programs.

“I think it is important to think in terms of whole world not just our portion of it. It would be a wrong use of energy and resources to direct our efforts toward dealing with the effects of climate change rather than efforts to prevent it,” he says.

He compares the problem to the proliferation of atomic weapons. “We should not be preparing for a nuclear attack–building bomb shelters–but banning and destroying nuclear weapons.”

Kay McVay, a Registered Nurse, California Nurses Association (CNA) Liaison Coordinator and former president of CAN, strongly believes that “Health care professionals and health care workers should be in the forefront of efforts to educate the public and to support strong measure to head off global warming.”

But she worries that “Nobody is being taught how to respond, there is no plan.”

“Our public health system has been decimated,” she says. “Hospitals have been closed by the hundreds, and RNs have been moved away from the bedside, and there is a shortage of public health nurses. We just don’t have the structure in place to handle it (climate change).”

One thing seems clear: given the inadequate finances of public health, people in the field are wrestling with hard choices of where to bullet their efforts.

Like the knee bone to the thighbone, higher temperatures have a cascading effect on a number of environmental factors. Severe drought is presently affecting one in six countries and has already created a continent-wide crisis in Africa. “Southern Africa is definitely becoming drier and everyone there agrees the climate is changing,” Wulf Killman of the UN’s Food and Agriculture Organization’s Climate Change Group, told the British Guardian.

Some 34 African countries, with upwards of 30 million people, are experiencing drought and consequent food shortages. “Drought affects people’s ability to feed themselves. A lack of food means a weakened population, one that is more susceptible to disease,” says Moser, ” and if you are stressed to the max, you don’t need much of an extreme event to push you over the edge.”

When people do go over that edge, there is virtually no net to catch them. A 2003 study by the World Health Organization (WHO) found that while developing countries carry 90 percent of the disease burden, they have only 10 percent of the world’s health resources. WHO estimates that 23,000 of Africa’s best trained health workers emigrate to Europe and the west each year, leaving only 800,000 doctors and nurses for the entire continent.

While aid can mitigate some of that burden, according to “Africa-Up in Smoke?” by the Working Group on Climate Change and Development—a coalition of organizations ranging from Oxfam to Greenpeace—aid is not enough. “All the aid we pour into Africa will be inconsequential if we don’t tackle climate change,” says Nicola Saltman of the World Wide Fund for Nature, a member of the Group told the Independent.

Climate change does not mean that the world gets drier everywhere. “Global warming means some places are going to get wetter, which is perfect for mosquitoes,” says Dr. Don Francis of Global Solutions. Francis, a former epidemiologist for the Center for Disease Control and an expert on diseases like smallpox, HIV and Ebola, predicts that “Infectious diseases, particularly those with vectors like mosquitoes, will move north. And with warmer temperatures and milder winters there will be longer transmission periods for diseases like malaria and encephalitis.”

That process is already underway. According to Dr. Jonathan Patz of the University of Michigan, malaria has surged since the 1970s, and expanded into areas–like the Colombian highlands–that were formally off limits to its vector, the Anopheles mosquito.

Malaria kills between one and two million people, and generates some 300 million to 500 million new cases a year. The malaria plasmodium is also increasingly resistant to standard treatment with chloroquine, although a new palette of drugs based on artemisinin extracted from the sweet wormwood bush has been effective.

However, while chloroquine costs 10 cents a dose, the new drug from the pharmacology giant, Novartis, runs $2.50 a pop. Artenisinin should also be taken with fatty meals, not normally a part of the developing world’s menu.

While malaria is the most dangerous of these mosquito borne diseases, there are other unpleasant beasts out there, including dengue, or “break-bone fever,” which infects 20 million people a year and kills more than 24,000.

Yellow fever could also spread, as might more exotic diseases like chagus, a trypanosoma that damages the heart and is spread by the nocturnal assassin bug. chagus, which takes about 50,000 lives a year, is endemic in Latin America, and closely associated with poverty and sub-standard housing, which gives the carrier places to hide during the day.

There is a close link between vector-borne diseases and unstable weather, the latter a major consequence of global warming. According to a 2003 World Health Organization study, “Climate Change and Human Health-Risks and Responses,” dengue epidemics are closely associated with El Nino events, when the surface of Pacific Ocean heats up and brings on warm and wet conditions. Malaria epidemics increase five-fold as well.

The same study found similar patterns with malaria in India when monsoon rains are heavy and humidity high.

In a 40-year study of Bangladeshi medical records, Mercedes Pascual of the University of Michigan found that climate change increases the incidence of cholera by spreading the disease through either floods or droughts. In the latter case, restricted water supplies are more vulnerable to disease causing organisms.

Recent heavy rains in West Africa have seen cholera rates more than double. More than 31,000 have been stricken since June. Flooding and drought also spread water borne diarrheal diseases like shigella, dysentery and typhoid, which kill over two million people each year, the majority of them children. Flooding also helps rodents disseminate diseases like hantavirus, tularemia, and bubonic plague.

Melting continental ice, coupled with the expansion of the oceans through warming, is projected to raise sea levels anywhere from three and a half inches to three feet by 2100. This will not only inundate lowlands where hundreds of millions of people presently live, it will generate more powerful storms.

According to the Massachusetts Institute of Technology study, tropical storms have increased in intensity by 50 percent in both the Atlantic and the Pacific over the past 30 years. “Future warming may lead to an upward trend in tropical cyclones’ destructive potential, and, taking into account an increasing coastal population,” says the MIT’s Kerry Emanuel, and “lead to a substantial increase in hurricane-related losses in the 21st century.”

Tropical storms all draw their power from warm water. The hotter the water temperature, the stronger the storm. Hurricane Katrina was a case in point.

Hurricanes, heat waves and vector-borne diseases are the most obvious effects of global warming. Other outcomes, like asthma, are hidden in a web of interconnecting events.

U.S. asthma rates have increased 40 percent in the last 10 years, afflicting 25 million Americans, nine million of those children. It is the number one cause for school absenteeism, and between lost work days and medical care, costs the country about $11 billion a year. Hospitalization for asthma is at record levels, particularly for African American children

This latter figure, however, may have more to do with social policy than asthma rates among certain populations. “African-American kids are hospitalized at four times the rate as Euro-American kids in Contra Costa County,” says Brunner, but says that is because they don’t have quality care. “Kids in Walnut Creek and Danville (affluent areas of the County) don’t end up in hospitals because they do.”

There are, however, asthma “triggers” which global warming is accelerating. A major component of air pollution is ozone, and “ozone is definitely a proven asthma trigger,” Brunner says.

Pollen, which can cause allergies and asthma, is likely to increase with climate change . Studies by Dr. Paul Epstein found that ragweed pollen, a major cause of allergies, will soar 64 percent if CO2 levels double, as predicted by the year 2050. Studies of Loblolly pines in North Carolina reached the same conclusion.

As daunting as problems like asthma seem, a little effort can make a major difference. A Canadian Public Health Association study of the 1996 Atlantic Olympics found that when the city restricted auto traffic for the 17 days of the games, ozone levels fell 30 percent, and emergencies and hospitalizations for asthma dropped 40 percent.

Because of the Bush Administration refusal to touch the subject of global warming or impose mandatory controls on greenhouse gases, a number of states and cities have begun to take action on their own. Nine northeastern states have signed on to their own version of the Kyoto Treaty, agreeing to reduce CO2 levels by 10 percent over the next 15 years. Hundreds of cities across the country have signed on.

Seattle has built a monorail, streetcars, and offers residents free city-owned hybrid gas cars, runs municipal vehicles on bio-diesel fuel, and has restored 2500 acres of urban forest. As a result, the city cut greenhouse gases by 48 percent from 1990 to 2000.

“There is much that is doable,” says San Francisco’s Bhatia. “The effects of global warming being projected are not inevitable. We can do much to prevent it.”

He cites a California EPA study which found that 58 percent of CO2 is produced by transportation, a figure that will increase as the State’s population grows. Only five percent of the city’s residents use public transportation exclusively. We can double that number soon.”

“Can we do something about global warming?” asks Moser. “Hell, yes!”

She points to the recommendations of the CUS report: increased disease surveillance, temperature warnings, cooling stations, and education. And better health care. “Many people don’t have health care, but that is the system that will have to deal with the consequences of climate change. We haven’t had that conversation in this country yet,” she says.

Americans, she argues, are willing to tackle the problem. “People want to do something positive, to leave a legacy. You have to appeal to that part of them. People understand you have to go though a little pain for long term benefits. They put money away for their kids to go to college, they buy insurance.”

The Program on International Policy Attitudes found that 56 percent of Americans would be willing to incur significant economic costs to address global warming, and 73 percent said the U.S. should join the Kyoto Accords.

But Moser says the involvement by the federal government is essential. “You can’t give up driving your car if there are no buses, or no bus shelters, or they cost too much.”

Francis concurs. “Government could have a tremendous impact on this. Remember seat belts? We got the data, passed laws, and people started wearing seat belts.”

Gelbspan even sees a certain silver lining in all this. “We live in a deeply fractured world. Here is an opportunity to bring all the nations of the world together. We can move beyond stale nationalism, create jobs, and undermine the economics of poverty and desperation.”

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