A tally of lost lives and health care expenditures arising from just six recent weather-related or epidemiological events suggests that the economic toll of future climate change is likely to be even more staggering than previously thought, according to a study published Monday in the journal Health Affairs.
The analysis, conducted by a team of researchers from the Natural Resources Defense Council, the University of California, Berkeley, and the University of California, San Francisco, represents one of the most ambitious attempts to establish a uniform method for putting a price tag on the health impacts of climate change. Most previous estimates have only looked at costs associated with property losses, damage to infrastructure and other resource forfeitures.
"This is a problem with a human face," said Kim Knowlton, a senior scientist in the Health and Environment Program at the Natural Resources Defense Council and the lead author of the study. "Our prior notions about climate change damage without these costs included have been vastly underestimated."
The researchers examined morbidity and mortality data -- including expenditures for hospitalization, visits to the emergency room and other medical services -- arising from a California wildfire in 2003 and a 2006 heat wave in the same state; the 2004 hurricane season in Florida; an outbreak of West Nile virus in Louisiana in 2002; a river flood two years ago in North Dakota; and nationwide ozone pollution between 2000 and 2002.
Although none of these scenarios can be definitively linked to climate change, all six were chosen as emblematic of the types of episodes that experts expect to see more of as the planet warms. They were also selected, Knowlton said, because robust health impact data for each was available in the peer-reviewed literature.
In reviewing that data, the researchers concluded that these six events resulted in 1,689 early deaths, 8,992 hospitalizations, 21,113 emergency department visits and 734,398 outpatient visits, with estimated costs totaling more than $14 billion. Almost all of that expense -- 95 percent -- arose from the foreshortening of human life. The researchers used a valuation developed by the Environmental Protection Agency that puts the health cost of each premature death at $7.9 million. Encounters with the health care system in these six scenarios accounted for as much as $740 million.
The highest health costs were associated with ozone pollution, which tallied $6.5 billion, and the California heat wave, which came in at $5.4 billion.
Differences in how cost data was tabulated in each event and other points of variability, the authors concede, may have resulted in the tally being overestimated by as much as $9.6 billion -- or underestimated by as much as $25.6 billion. But given the expected rise in the number of heat waves, flooding, and other extreme weather- and disease-related events associated with global warming -- in addition to established projections for the impact of climate change on physical infrastructure and other non-human capital -- the study suggests that the total price tag is likely to be exponentially higher than previously thought.
Other potential expenditures -- from increased rates of food- and waterborne illnesses and lost school days for children to the costs associated with climate change's disproportionate impact on poorer communities -- also have not yet been tallied, the authors note.
"These numbers are big," Knowlton said, "and it's important that we begin to think about and address these health costs and what climate change is likely to mean for people's health."
Tabulating the potential costs of climate change to society has become an increasingly important pursuit for policy planners, particularly given the lack of global agreement on measures to combat the phenomenon, as well as the inability of the United States, the world's largest per-capita emitter of greenhouse gases, to pass domestic legislation that would begin curbing such emissions.
A 2008 analysis commissioned by the Natural Resources Defense Council, for example, estimated that hurricane damage, real estate losses, energy and water costs associated with global warming could cost as much as $1.9 trillion annually by the end of the century. Various other studies, including one by the British economist Nicholas Stern, have put the potential cost at anywhere between 1 percent and 5 percent of the total national product of all countries, or the gross world product, which is currently estimated to be just over $63 trillion.
The authors of the current study suggested that the costs could be reduced through policies aimed at ensuring adequate preparation -- heat wave warning systems at the community and workplace level, for example, or reductions in ozone-contributing pollution.
Currently, 13 U.S. states have established specific public health measures as part of wider climate change adaptation plans. Last week, Rep. Lois Capps, a California Democrat, introduced legislation that would "direct the Secretary of Health and Human Services to develop a national strategic action plan to assist health professionals in preparing for and responding to the public health effects of climate change."
The bill was referred to the House Committee on Energy and Commerce.