Getting

By Alison Fromme & Sharon Tregaskis

Scientists zero in on the health implications of a changing climate.

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YOU’VE HEARD THE QUESTION BEFORE, but in this case it’s not just small talk. Knowlton, an assistant clinical professor of Environmental Health Sciences, has dedicated her career to unraveling the relationship between changing mete-orological patterns and public health. “Climate change isn’t just inconvenient,” she says. “It kills people.”

She should know. Knowlton’s doctoral dissertation at the Mailman School—completed just a few months before Hurricane Katrina put the collision of cli-mate and health on the public radar—forecast the number of deaths likely to follow from increasingly frequent heat waves and high ozone levels in New York City. More recently, Health Affairs published her calculation, done with a team of economists and colleagues from the National Resource Defense Council, of the costs associated with mortality, illness, and health expenditures due to six discrete climate-change events in the United States between 2000 and 2009. Their tally: a staggering $14 billion, 95 percent of which came from valuations of lives lost. Estimated healthcare costs, for some 760,000 encounters with the healthcare system, amounted to $740 million.

With a focus on index events—nothing too extreme—the team didn’t even tackle costs associated with Katrina. Or Irene. Or Sandy. Scholars have yet to embrace a set methodology for making such calculations, and Knowlton suspects the Health Affairs study was a gross underestimate. “Climate change-related events are costing Americans billions,” she says, rattling off a list of hazards to mind and body including depression, posttrau-matic stress, asthma, respiratory damage from mold, heat stroke, and organ failure, as well as fatalities from drowning, water-borne illness, and disease. “We all want to avoid those costs—as well as the pain, suffering, and lessened quality of life they represent,” she says. “As public health pro-fessionals, we have to help policymakers understand that anticipating the influence of climate change on Americans’ well-being and preparing accordingly isn’t optional.”

As climate change accelerates, expect extremes to become a way of life: more bad air days due to ozone pollution; longer heat waves; more intense hurricanes; dangerous new infectious disease outbreaks; extreme

Climate change isn’t just inconvenient. It kills people.

flooding and drought; wildfires that start more frequently and burn longer. Knowlton and her colleagues in the Columbia Climate and Health Program—the first of its kind in the world, established in 2009 and housed in the Mailman School’s Department of Environmental Health Sciences—are elu-cidating the climate-health connection and advancing society’s capacity to understand, anticipate, and perhaps even prevent the health risks sure to follow.

The complete list of consequences for human health is long, says Patrick L. Kinney, scD, a professor of Environmen-tal Health Sciences who founded and now directs the Program. The team’s nine faculty and four graduate students delve into the mechanisms, emerging trends, and future impacts of climate change on human health, as well as the immediate health benefits associated with mitigation policies directed at reducing greenhouse gas emissions. “The field is in its infancy,” says Kinney, who pioneered the study of climate, air quality, and health outcomes more than a decade ago. “Our research has only begun to scratch the surface.”

Meanwhile, Knowlton, Kinney, and their colleagues at the Mailman School have already begun consulting with national and local politicians to begin preparing for what’s to come. Knowlton, the country’s

first DrPH trained in the field, serves as a senior scientist with the Health and Environ-ment Program of the Natural Resources Defense Council (nrDc), a nonprofit environ-mental advocacy group. She is also a member of nrDc’s Sci-ence Center and a member of the Climate-Health Adapta-tion Workgroup, part of Mayor Michael Bloomberg’s Office of Long-Term Planning and Sus-tainability.

In January, Bloomberg ap-pointed Kinney—Knowlton’s doctoral advisor and the sole public health representative—to his New York City Panel on Cli-mate Change. Six months later, the mayor released the panel’s

How’s the weather?” asks Kim Knowlton, DrPH ’05.

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1 Drought, low humidity, and high winds fuel a wildfire season that burns longer each year. Red scars in this 2011 satellite image highlight the one million acres burned in just two weeks by central Texas wildfires. IMAGE: NASA/GSFC/LANDSAT 5

2 In October 2012, Hurricane Sandy killed 286 people and wrought more than $68 billion in damages in seven countries. Along the mid-Atlantic coastline, cleanup continues. PHOTO: ADRIAN KINLOCH

$14 BILLION

95%

Costs associated with mortality, illnesses, and health expenditures due to six discrete climate-change events in the United States between 2000 and 2009

Portion of that figure due to the valuation of lives lost

Heat-related deaths in Manhattan

RED INDICATES BURN SCARS. VEGETATION

IS GREEN, WATER IS BLUE, AND BARE

GROUND IS PINK AND LIGHT RED.

Estimated increase over the next decade

Amount due to healthcare costs = $740,000,000

20%

report to the public. Among its findings: By 2050, temperatures will have climbed 4 to 6 degrees; precipitation will have increased by 4 to 11 percent; sea levels will have risen by 1 to 2 feet. “Hurricane Sandy made it all too clear that, no matter how far we’ve come, we still face real, immediate threats,” says the mayor, who expanded on the panel’s recom-mendations with a series of his own propos-als for protecting Gotham residents. “This is urgent work and it must begin now.”

Hot TopicMuch of Kinney’s work has focused on the effect of rising temperatures, especially on such vulnerable populations as the aging—at greater risk of heat stroke and organ fail-ure because of their physiology—and those who are economically disadvantaged, and thus less likely to have easy access to air con-ditioning when the mercury soars. “We’re definitely going to experience more heat in the next few decades,” says Kinney, who notes that even if we were to begin slashing greenhouse gas emissions today, atmospher-ic self-correction could take centuries. “No matter what we do, it’s going to get warmer.”

In a study published in May by Nature Climate Change, Kinney used historical re-cords to reveal that during the 20th cen-tury, average temperatures in Manhattan’s Central Park increased 3.6 degrees Fahr-enheit—substantially more than global and U.S. trends. Using a combination of methods to forecast weather patterns, they found that heat-related deaths in Manhattan could rise by 20 percent over the next decade. Although increasing temperatures are ex-pected to save some lives during the winter heating season, those improvements will not completely offset the projected number of deaths during summer months.

With any such project, says Kinney, un-certainty persists. “Whenever you make a big change in something as fundamental as temperature and rainfall patterns, it’s going to have all kinds of unforeseen consequ-ences,” he says. Factor in public health pro-jections, and additional layers of complexity emerge. “Health and climate are tough to study over long periods because there are so many other variables affecting health,” he says. “It’s not like studying a glacier that only responds to temperature and precipitation.”

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Infectious DiseaseThe connection between health and infectious disease is a particularly knotty problem. When temperature and rainfall patterns shift, so do populations of the wild things that serve as vectors for disease. Already, tick populations—and the diseases they spread—have increased with higher average winter tempera-tures. Some climate change models predict heavy rainfall in New York state; mosquitoes might thus find more stagnant water for breeding in the future. But does that mean higher rates of West Nile virus? Or a resurgence of malaria?

To find out, scientists must first answer a series of more basic questions. “We need to know how diseases are sensitive to climate, here and now,” says Jeffrey L. Shaman, PHD ’03, an assistant professor of Environmental Health Sciences. “And only then can we think about the relationship between disease and climate change more generally.”

Influenza, for example, has long been known to vary seasonally, yet the mechanisms precipitating those patterns remained murky. In 2009, Shaman linked the occurrence of temperate-climate flu to low absolute humidity, which appears to help the virus survive. In a subsequent paper, he and his coauthors revealed how thresholds factor into the equation, explaining why infections actually increase during the rainy season in the tropics, contrary to the pattern in temperate zones.

Borrowing methods from meteorological modeling, Shaman has since used those insights to create real-time influenza forecasts, an initial step in the develop-ment of a statistically rigorous flu prediction system. As he fine-tunes the model with further research—and possibly incorporates climate variables—he expects that the Centers for Disease Control and local municipalities could use his work to support decisions regarding the distribution of vaccines and antiviral drugs.

1 When heat waves strike, those who can turn to their air conditioning. For vulner-able New York City popula-tions—including kids and the elderly—open hydrants and cooling centers offer relief.

2 A worst-case scenario projects that the health effects of sizzling summers may cost 1,000 New Yorkers their lives every year.

3 Infections caused by the influenza virus (orthomyxoviridae) ebb and flow with the weather. Elucidating the link led to real-time fore casts to inform management plans. IMAGE: SANOFI PASTEUR

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SolutionsNew York City is already responding to the threat. Cooling centers welcome people without access to air conditioning. The city’s Department of Health and Mental Hygiene (DoHMH) has refined its heat warn-ing system and identified vulnerable populations. “These aren’t theoretical problems,” Kinney says. “New York City is leading by example.”

Case in point: Kinney’s PHD student Kate Weinberger, a lifelong asthma sufferer, has installed 45 pollen monitors, coupled with air quality monitors maintained by DoHMH, throughout New York City. In 2012, Kinney and Weinberger joined forces with DoHMH scientists to link pollen counts, which are ex-pected to rise with climate change, and emer-gency room visits. Now, DoHMH uses pollen data to send allergy advisories directly to physicians, who can prepare themselves and their patients for specific spring outbreaks.

“Climate change is real, it’s happening, and we need to prepare,” says Kinney. “Long-range planning and the research to guide it are essential if we are to avoid the worst consequences of climate change. It’s not insurmountable.”

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MANY NYC RESIDENTS DON’T HAVE THE LUXURY

of turning on the air conditioning when it’s hot, or cranking up the heat on a freezing winter day. The cost is just too high, particularly for vulner-able populations.Known as energy insecurity, the problem manifests itself in extreme indoor temperatures and the constant threat of utility shut offs. Ther-mal regulation at home is not just a matter of comfort—it’s necessary for survival, says Diana Hernández, PhD, an assistant professor of Sociomedical Sciences. Extreme temperatures affect sleep, and sleep deprivation lowers job performance and exacerbates existing health issues. Impoverished people are more likely to suffer from respiratory problems, which are linked to excess indoor moisture and air pollution resulting, in part, from inadequate or inefficient heat and insulation in their homes. They are also more likely to fall ill or die from extreme heat or cold stress.

“These are serious problems,” Hernández says. “But solutions are available.” The U.S. Department of Energy’s Weatherization Assistance Program offers funds to low-income families for energy efficient up-grades; Hernández studies the resulting health and financial impacts. Structural improvements such as stopping drafts, for example, might enable a family to use their conventional heating system, instead of resorting to the oven as a source of quick warmth. In turn, an indoor environment less polluted by combustion products released by the oven might lead to fewer emergency room visits for asthma attacks.

Hernández is also examining the effect of NYC’s Local Law 42, which mandates the conversion of boilers to burn cleaner fuels. Using indoor and outdoor filters, she is measuring exposure to particulate matter before and after the conversions and documenting the experi-ences of individuals living in affected homes.

Beyond her interest in these issues as a researcher, Hernández has a personal stake. Four years ago, she returned to the South Bronx, where she grew up, and purchased two rental properties. She’s reno-vating them with a series of energy upgrades. “We can never go back in time to address climate change,” she says, “but we can interject at this point to reduce emissions.”

Heat or Eat

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