Continuing Eli's lazy stroll through the US EPA responses to comments. They are serious folks.
A commenter (8320) submits information and references on the potential health effects of global climate change. The commenter discusses the following topics: extreme heat events, wildfires, vector-borne diseases, water-borne diseases, air quality and human heath, aeroallergens and allergies, environmental justice, and the vulnerability of children to effects from air quality. The commenter stresses that “climate change will alter the global environment and present major challenges to the health and welfare of children.”
EPA has reviewed the submitted comments and associated references, and finds that they include several very recent and relevant studies (e.g., St. Louis and Hess, 2008; Patz et al., 2008; Jerret et al., 2009) that confirm the scientific support for health related impacts summarized in the TSD.
In one example, Luber and McGeehin (2008) call extreme heat events “the most prominent cause” of weather-related human mortality in the United States, noting that they are responsible for more deaths annually than hurricanes, lightning, tornadoes, floods, and earthquakes combined. We note that the recently released U.S. Global Change Research Program (USGCRP) report (Karl et al., 2009) also concludes that mortality from heat is the number one weather-related cause of death and cites an analysis of nine U.S. cities showing that deaths rise with increases in temperature and humidity with no confounding or effect modification due to air pollution (Zanobetti and Schwartz, 2008).
Another recent study (Jerret et al., 2009) provided by the commenter indicates that high levels of ground-level ozone can increase the risk of asthma-related hospital visits and premature mortality and that the effect of long-term exposure to ozone on air pollution–related mortality was not known. The study indicates that ozone exposure is associated with the risk of death from respiratory causes, and that long-term, low-level exposure can be lethal. Researchers studied the outcomes of almost 500,000 adults in 96 metropolitan regions who enrolled in the American Cancer Society Cancer Prevention Study in 1982 and 1983 and were tracked for an average of 18 years. In addition, the study by Jerrett et al. (2009) looked at associations between ozone concentrations and the risk of death, in a single-pollutant model and in a two-pollutant model with fine particulate matter (PM2.5). In two-pollutant models, researchers demonstrated a significant increase in the risk of death from respiratory causes in association with an increase in ozone concentration. The study found that every increase in 10 parts per billion (ppb) in average ozone concentrations was associated with a roughly 4% increase in mortality from respiratory causes. This translated in Los Angeles to a 43% increase in the risk of dying from respiratory causes. Eastern cities like New York and Washington had an average increased risk of about 25% to 27%. EPA concludes this study fills important knowledge gaps in health impact literature from increases in ozone exposure (at low levels).
Another study provided by the commenter provides evidence of vector-borne disease shift attributed to climate. For example, in Europe, geographic shifts in the tick’s distribution have been attributed to climate change. An expansion of the tick’s range into higher elevations in the Czech Republic corresponded to rising temperatures. A shift toward higher latitudes in Sweden corresponded to a reduction in the number of very cold winter days (Gage et al., 2008).
Based on review of the cited literature from the commenter, we conclude that the information provided is generally consistent with, and in several cases even stronger than the assessment literature summarized in the TSD.