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Climate Change Health Costs Add Up to One Big Bill

Florida was hit by four hurricanes in 2004, yielding a litany of health concerns. Carbon monoxide poisoning alone cost $1.4 billion.
A new analysis calculates the costs for treating increased illnesses and injuries in a warming world

In the summer of 2001, Craig Stephen got a call. A dead porpoise had washed up on Vancouver Island; could he take a look? Examining the carcass in his lab, Stephen, the president of the Centre for Coastal Health and a veterinary epidemiologist at the University of Calgary, realized immediately that the animal’s lungs had been damaged. "They felt like liver," he recalls. Lab tests soon showed that the porpoise had been infected with a fungus called Cryptococcus gattii. "That’s weird," Stephen thought: C. gattii is a tropical and subtropical organism. "How did a nice tropical fungus get to a cool place like Vancouver?"

The answer could be as simple as the disease hitching a ride on a tropical vacationer, but a more alarming possibility has emerged over the past decade: that changes in climate are allowing disease-causing organisms to expand their range well out of the tropics. The initial outbreak that killed the porpoise, says Stephen, eventually hit dogs, cats, a house ferret, pet birds, horses, squirrels -- but by the following March, 50 people had been infected. The fungus causes respiratory illness and can be deadly: by 2007, there had been 218 C. gattii cases in humans and 19 deaths. By 2005 it had reached the United States, where by last year it had caused six fatalities in 21 cases, an early example of a larger phenomenon. "This could be a signal event telling us that things had changed in our environment in a way that can harm health," says Stephen.

Since at least 1989 physicians and public health officials have warned that global warming could threaten human health (see "The New Diseases on Our Doorstep," Fall 2009), but unlike the costs of building higher sea walls or calculating crop losses from floods, they haven’t been able to put a price tag on the health effects of climate change -- until now. As more people are felled by heat stroke, injured by stronger hurricanes, and stricken by C. gattii and other once-tropical diseases, what is likely to be the economic hit?

In the first study of its kind, Kim Knowlton, an assistant clinical professor of environmental health sciences at Columbia University’s Mailman School of Public Health and an NRDC senior scientist, and Miriam Rotkin-Ellman, a public health and environmental scientist in NRDC’s San Francisco office, have analyzed six events of the kind projected to become more frequent or more extreme as a result of climate change and calculated their financial costs due to premature deaths, injuries, and illness. Using a case-study approach, Knowlton and Rotkin-Ellman gathered cost data from both peer-reviewed scientific papers and reports from state and federal agencies. The bottom line, they report in a paper released online today and appearing in the November issue of the journal Health Affairs: $14 billion for just six climate-related disasters since 2000.

"Estimates of the financial cost of climate change run into the billions of dollars annually," Knowlton says. "But health costs were not part of these estimates, and were also absent from public policy discussions. That’s an enormous oversight."

The Health Affairs analysis is an interesting addition to recent papers showing that even economically developed nations such as the United States can expect significant economic costs from climate change, says James Ford, assistant professor in the Climate Change Adaptation Research Group at McGill University. Those climate-related costs present a major concern at a time when government budgets are already shrinking and health care costs are rising due to an aging population and other factors.

To be sure, compared to overall health spending -- more than $2.5 trillion, with some $800 billion from private insurers -- climate-related health costs may initially seem to be hardly more than a rounding error. But the $14 billion "is certainly an underbid" in terms of the annual health-care costs of climate change, says Knowlton. That’s because each of the six calamities they studied -- high levels of ozone pollution; a heat wave; hurricanes; a vector-borne disease outbreak; river flooding; and wildfires -- is likely to strike the U.S. more than once a year, and suffering one disaster doesn’t mean a state or region won’t be struck by another. The $14 billion is therefore just a fraction of what health costs related to climate change are likely to suck out of cities, states, businesses, and individuals every year.

The cost of each event that Knowlton and Rotkin-Ellman studied suggests how quickly the tab might rise:

Ozone emergencies: As temperatures increase, so does the formation of ozone, which impairs lung function and causes inflammation of the airways. That makes it more likely that vulnerable people -- the very old, the very young, and the ill, especially those with respiratory conditions such as asthma or chronic obstructive pulmonary disease, or COPD -- will wind up in the ER. Exposure to elevated concentrations of ozone is indeed associated with increased hospital admissions for pneumonia, COPD, asthma, allergic rhinitis and other respiratory diseases. Using a 2005 study by EPA scientists, Knowlton and Rotkin-Ellman calculate that dangerous levels of ozone cause $6.5 billion in U.S. health costs per year, including premature deaths.

Heat waves: The 2003 heat wave in Europe killed an estimated 35,000 people or more; thousands died in recent heat waves in India and Russia. Because nighttime temperatures are climbing twice as fast as average temperatures (bringing less relief after sunset), and because the warmer atmosphere holds more water vapor, which brings misery-making humidity, "the combination makes heat waves today all the more lethal," says Paul Epstein of Harvard Medical School’s Center for Health and the Global Environment.

The Health Affairs analysis focused on the 2006 California scorcher, when both the maximum and minimum records were broken from the Oregon border to Mexico for two weeks in late July, and the Central Valley broke its record for the most consecutive days with temperatures of 100 or more. A 2009 paper by Knowlton, Rotkin-Ellman, and others found that there were 16,166 more ER visits during the heat wave than the norm, plus 1,182 additional hospitalizations -- mostly for acute renal failure, cardiovascular diseases, diabetes, electrolyte imbalance, and nephritis, all of which can be caused by heat. Total cost from the resulting morbidity and mortality: $5.4 billion. The 2006 heat wave was considered a once-in-a-century occurrence -- but it could become an annual event by late this century, according to climate projections.

Hurricanes: Knowlton and Rotkin-Ellman focused on the 2004 Florida hurricane season, when Charley, Frances, Ivan, and Jeanne ripped through the state. (Hurricanes are projected to become stronger as the seas from which they draw their power warm.) The major health consequences of the 2004 storms included disease from contaminated floodwaters, carbon monoxide poisoning (from improper use of gas-powered generators after power failures), and psychological illnesses such as post-traumatic stress disorder as survivors struggle to cope. Carbon monoxide poisoning alone resulted in $1.4 billion in health costs, including mortality. The bill would be even higher if it included the cost of treating anxiety disorders and other illnesses, which are not as well documented.

Wildfires: Hospital admissions rose during the 2003 wildfires in southern California, a 2009 paper found, mostly for respiratory and cardiovascular events such as bronchitis, COPD, and pneumonia. As a result, the new study calculates, the fires were responsible for $33 million in additional health-care costs and $545 million in lives lost or cut short. And that is from a single incident. As heat waves and drought dry out forests and grasslands, research by Tony Westerling of the University of California, Merced, and colleagues suggests, California will have 21 percent more large wildfires than the recent historical average in the next two decades, and 84 percent more by the end of the century.

Vector-borne diseases: "Climate change encourages the spread of infectious diseases in two ways," Harvard Medical School’s Epstein says. With global warming, vector-borne diseases are expanding their range, he notes: the range of tick-borne Lyme disease is increasing as winters warm, with an eight-fold increase in New Hampshire in the past decade and a ten-fold increase in Maine. Knowlton and Rotkin-Ellmann focused on Louisiana’s 2002 outbreak of West Nile virus, a mosquito-borne disease that can cause neurological symptoms from fever to paralysis. The tab came to just under $18 million for ER, hospitalization, and outpatient costs; putting a price tag on the lives cut short boosted the toll to $207 million.

Floods: Rivers are surging over their banks more frequently as the warming world intensifies the hydrological cycle -- that is, when it rains, it pours. Floods often bring an increase in respiratory and diarrheal disease, as well as injuries from the physical stress of hauling sandbags and other flood-prevention efforts. The 2009 Red River floods in North Dakota were responsible for just under $5 million in health-care costs, or $20 million including the value of lost lives.

All told, the six events that the Health Affairs investigators studied caused 1,689 deaths, 8,992 hospitalizations, 21,113 ER visits, and 734,398 outpatient visits with resulting health costs of $14 billion. The value of the lives lost constitute 95 percent of that total. Caring for the sick and injured cost $740 million.

The figures almost certainly underestimate the economic costs. For example, flooding tends to increase rat populations, which can lead to the spread of hantavirus; that did not happen in North Dakota, but other flooded regions might not be so lucky. Allergenic diseases are expected to increase as higher temperatures and higher concentrations of carbon dioxide increase the production of ragweed pollen and extend the ragweed season. And because the greenhouse effect cools the stratosphere even as it warms the lower atmosphere, the effect of ozone-depleting gases will be prolonged, allowing more carcinogenic ultraviolet rays to reach the ground and cause skin cancer.

Nor does the analysis take into account the indirect effects of climate change. As climate zones shift, and floods and droughts become the norm, crop yields will fall and food shortages will become more likely. And as rising sea levels and other disasters trigger massive migrations, many people will move into areas where infectious diseases to which they have no immunity are endemic. Similarly, new arrivals may carry with them diseases to which the existing population has no immunity -- think Native Americans encountering diseases the Europeans brought.

Most alarming, perhaps, is that public health agencies and others haven’t done enough to identify the most effective ways to confront the health consequences of global warming -- and some of the steps they have taken, such as tracking mosquito- and tick-borne diseases, are at risk from funding cuts. "It’s a pretty bleak picture," says McGill University's Ford. "Thanks to two decades of research, we have a pretty good idea of what the health effects of climate change will be. But figuring out how to manage those effects has a ways to go."

Several cities have tested programs designed to alert vulnerable people about a coming heat wave; Chicago has one of the best, including a network of cooling centers. But there is little research on how to move vulnerable people to those centers most efficiently, let alone evacuate them ahead of a storm (cf: Katrina), and few programs in place to do so. There are also serious questions whether doctors, especially outside of academic medical centers, would recognize a case of, say, malaria or dengue fever in time to alert public health agencies about the arrival of a deadly and contagious new (to the area) disease.

"There is widespread recognition of the need to prepare for [the health effects of] climate change, says Howard Frumkin, dean of the school of public health at the University of Washington, "but public health departments’ resources are shrinking. Most of them don’t feel ready and don’t know what they have to do to get ready."

The private sector also has its head in the sand. "It’s not even on the radar screen" of health insurance companies, says Sharlene Laurig, senior manager of the insurance program at Ceres, a not-for-profit that works with companies on environmental issues. "They don’t see climate change as affecting their business, but it’s going to cause them to incur additional costs." With health care already eating up 17 percent of the U.S. economy, these new costs couldn’t come at a worse time.

image of Sharon Begley
Sharon Begley was the science editor and the science columnist at Newsweek from 2007 to April 2011, and is now a contributing writer at the magazine and its website, The Daily Beast. From 2002 to 2007, she was the science columnist at The Wall Street... READ MORE >