摘要：Objectives. To quantify the increased disease burden caused by US health care sector life cycle greenhouse gas (GHG) emissions of 614 million metric tons of carbon dioxide equivalents in 2013. Methods. We screened for health damage factors that linked GHG emissions to disease burdens. We selected 5 factors, based on appropriate temporal modeling scales, which reflect a range of possible GHG emissions scenarios. We applied these factors to health care sector emissions. Results. We projected that annual GHG emissions associated with health care in the United States would cause 123 000 to 381 000 disability-adjusted life-years in future health damages, with malnutrition being the largest damage category. Conclusions. Through their contribution to global climate change, GHG emissions will negatively affect public health because of an increased prevalence of extreme weather, flooding, vector-borne disease, and other effects. As the stewards of global health, it is important for health care professionals to recognize the magnitude of GHG emissions associated with health care itself, and the severity of associated health damages. The central finding of The Lancet Commission on Health and Climate Change, that tackling climate change could be the greatest global health opportunity of the 21st century, resulted in several Commission recommendations to accelerate actions. These included the call for research to quantify disease burden and for health professional leadership to unite all actors behind the common cause of public health. 1 The US health care system contributes significantly to country-wide air and water pollution, and hence, to pollution-related health damages. 2 US health care activities were responsible for 9% to 10% of national greenhouse gas (GHG) emissions in 2013, which occurred both directly from health care facilities and vehicles, and in larger part, indirectly from upstream production of electricity, drugs, medical devices and supplies, and other goods and services that feed into the health care sector. Taken together, direct and indirect GHG emissions are called life cycle emissions or the carbon footprint of US health care. These life cycle emissions results update and corroborate earlier work by Chung and Meltzer. 3 In addition to GHG emissions, health care–associated emissions of several other types of pollutants were also quantified, 2 including those that contribute to acid rain (12% of the national total), photochemical smog (10%), and respiratory disease (9%). Public health damages from exposure to non-GHG emissions were subsequently estimated at 405 000 disability-adjusted life-years (DALYs) annually. Most of these DALYs were attributable to particulate matter emissions. These health damages are comparable in magnitude to preventable medical errors, 2 but they are incurred indirectly by the general public rather than directly by patients. They are also partially preventable, because reducing wasted resources that do not benefit patient outcomes also reduces upstream emissions and their associated damages. 4 We considered the possible range of health damages from health care–related GHG emissions specifically. These damages were not included in our earlier estimates of health care sector emission disease burden because of the wide variation in approaches used in their estimation―such as the socioeconomic and emission scenarios considered, inclusion or exclusion of particular health effects, potential adaptive responses, and modeling parameters―that can lead to order-of-magnitude differences in damage factors. Potential impacts of climate change on human health, well-being, and security have been characterized in detail and include thermal stress, flooding and extreme events, radiation, air pollution, infectious disease, malnutrition, and potential conflicts ( bit.ly/1RIYUkC ). The World Health Organization estimated that in 2004 climate change caused 141 000 additional deaths worldwide on an annual basis, with a projected 250 000 additional annual deaths that will occur from 2030 to 2050, considering the factors of heat stress, malaria, diarrhea, and malnutrition, and using an average GHG emissions scenario ( bit.ly/1tGJ5RS ). We linked these future global health damages to the portion of global GHG emissions of the US health care system.
