Shifting global energy use away from carbon-rich sources like fossil fuels and coal is a critical step to mitigate climate change, but it also would have profound benefits for public health, a panel of experts concluded at the 2009 AAAS Forum on Science & Technology Policy.
Kirk Smith, professor of global environmental health at the University of California- Berkeley, said that reducing the use of coal and traditional biomass such as wood for energy would greatly improve air quality—especially in the developing world—which overwhelmingly relies on them for energy.
Often used inside the home for cooking and heating, these sources release harmful particles and gases due to poor and incomplete combustion. Smith said that there are strong epidemiological studies showing that these byproducts have been linked to pneumonia, low birth-weight, lung and heart disease, blindness, cancer—and, ultimately, 1.6 million premature deaths per year. Outdoor air pollution from poorly managed fuel combustion adds additional health burdens.
"Bringing cleaner energy like solar, hydroelectric, or other non-carbon-rich resources to the developing world will have a clear effect on human health," said Smith, who participated in Working Group II and III of the International Panel on Climate Change  (2007).
Smith spoke on 30 April at the 34th annual Policy Forum alongside Carlos Corvalán, senior advisor in sustainable development and environmental health at the Pan American Health Organization in Brazil; Daniel Greenbaum, president of the Health Effects Institute; Andrew Dobson, professor of ecology and evolutionary biology at Princeton University; and Reid Detchon, executive director for energy and climate at the United Nations Foundation.
The Forum brought over 600 scientists, policy makers, and students, plus more than two dozen journalists, to Washington, D.C., for two days of discussions and lectures on the nexus of science and public policy. It was held just a few blocks from the White House at the Ronald Reagan Building and International Trade Center.
Sharon Hrynkow, panel moderator and associate director of the National Institute of Environmental Health Sciences, said that scientists have an important role to play in showing the direct and indirect benefits of addressing climate change, and in ensuring that policymakers have access to information on these links.
"Addressing climate change requires concurrent thinking across multiple scientific disciplines," said Hrynkow, echoing luncheon comments by MIT President Susan Hockfield. [See related story.] "Health and climate, both directly and indirectly, are intricately linked."
In addition to reducing harmful gases and pollutants by burning cleaner energies, Smith said reducing the number of vehicles on the road would decrease deaths caused by motor vehicle accidents and increase physical activity—encouraging bicycle use and walking; that would reducing the global obesity epidemic, which would have net effect of preventing more than 3 million early deaths per year.
Smith also echoed guidelines published in a Lancet study to promote an average of about 90 grams (slightly over three ounces) of red meat per person per day, which would reduce obesity in the developed world and malnutrition in the developing world, as well as reduce methane emissions from livestock and carbon from the meat production process. Current estimates suggest that average per person daily consumption in the developed world is 200-250 grams (roughly seven to nine ounces) of red meat a day, but only 25-50 grams in the developing world.
Smith said that red meat consumption has been linked to increased risk of stroke, heart disease, and bowel and breast cancer.
Efforts to reduce greenhouse gases also could include efforts to reduce the human population, which would mean not just fewer people to drive emissions, but better health for everyone.
"About the most cost effective greenhouse gas control device is a condom," said Smith, adding that "it's not about population control, but rather reproductive rights." With more control about when and where children are conceived, there could be a sharp reduction in infant mortality and maternal deaths during childbirth, as well as 1-2 billion fewer people by 2100.
Corvalán, an environmental epidemiologist, said that 88% of disease burden attributed to climate change affects children under the age of five. While addressing climate change would not eliminate all mortality, it could mitigate some the 3.5 million early deaths due to malnutrition, 2.2 million due to diarrhea and dehydration, and 900,000 due to malaria, which all disproportionately affect children.
"These diseases are highly sensitive to temperature and precipitation," said Corvalán.
Corvalán said that in May 2008, the World Health Assembly passed the Climate Change and Health Resolution, which unequivocally labeled the effects of global warming as health risks. This was followed by a September 2008 Pan American Health Organization Climate Change and Health Action Plan, which "sought to empower, equip and strengthen the capacity of health systems locally and nationally to protect human health from risks related to climate change." This includes training local health professionals to anticipate the growing health crises due climate change.
Greenbaum, who served as commissioner of the Massachusetts Department of Environmental Protection from 1998 to 2004, said that among the harmful byproducts of burning coal and fossil fuels is the creation of ozone, which is not released from factories or tailpipes but rather created when sunlight hits air with hydrocarbons and nitrogen oxides released during combustion.
Greenbaum said that ozone is the leading component of smog, and well known to cause inflammation in the respiratory tract, reduced lung function, asthma, with recent studies suggesting a possible link to premature mortality. He added that climate change is likely to make ozone an even more challenging problem, as "warmer temperatures favor the creation of ozone."
"We have substantial existing public health challenges from ambient air pollution today," said Greenbaum, "and climate is likely to significantly further exacerbate some of these problems by mid-century."
In 2008, President George W. Bush significantly tightened the standards for acceptable ozone in the atmosphere, increasing the number of U.S. counties with dangerous ozone levels from 85 counties to 345 counties. Greenbaum said that current Environmental Protection Agency Administrator Lisa Jackson has signaled her "intent to review and possibly further tighten this standard."
Detchon, who also serves as executive director of the Energy Future Coalition, said that reducing the use of aromatics in gasoline will reduce pollutants in the air and improve public health. Used in gasoline to increase octane, aromatics are toxic hydrocarbon compounds known to cause cancer and other serious health problems, including pulmonary disease and asthma.
Instead of adding aromatics to gasoline, Detchon encouraged the greater use of advanced biofuels like cellulosic ethanol, which he says will be available in adequate supply, have low to no incremental cost to the consumer, produce few greenhouse gases during combustion, reduce dependence on foreign oil, and are high-octane.
He also called for an increase in the production of electric cars. Detchon said that in the next few years, "we will begin to see electric cars that are lighter, contain smaller engines, and can drive up to 40 miles without using a gasoline reserve."
Dobson expanded on the need for training as part of his talk. "There are more knee surgeons in New Jersey than there are people that can thoroughly explain disease transmission," said Dobson. "We must train people who can better predict where diseases will be so we can get out in front of them."
Using cholera and malaria as exemplars, Dobson explained that there are many climate-sensitive factors involved in the transmission dynamics of disease and that people, animal and insect vectors, and microbes all respond differently to climate variability.
He called for increasing the capacity for researchers in poor countries to be able to develop predictive models of disease transmission using local data. "By looking at the whole ecosystem, we are better positioned to understand disease dynamics and to develop effective intervention strategies," he concluded.