When the world's nations set a goal in Paris last year of limiting the average temperature increase to no more than 2 degrees Celsius, the impact on health wasn't front and center. But, a study published today in Nature Climate Change suggests that if the United States reduces emissions from the transportation and electricity sectors in order to meet those targets, 295,000 American lives could be saved by 2030.
Researchers from Duke University modeled emissions scenarios for the electricity and transportation sectors—the two biggest contributors to air pollution and carbon emissions—and calculated the effects of those scenarios to human health and climate in the near and long term, as well as both locally and globally.
The researchers also evaluated the economic impacts of those scenarios, taking into account the value of the lives saved and monetizing the value of emissions reductions.
Overall, they found that implementing a renewable energy policy in accord with the targets would result in preventing 175,000 premature deaths by 2030 and 22,000 fewer each year after. Implementing a clean transportation policy could prevent 120,000 premature deaths by 2030 and 14,000 premature deaths each year after.
In addition, they estimated that the near-term economic benefits could be US $250 billion per year, exceeding the potential $70 billion to $90 billion it could cost to implement the policies. Long-term, worldwide benefits could be five times greater.
The study "adds to the growing body of literature of the health co-benefits of addressing climate change," says Jonathan Buonocore, program leader of climate, energy and health at Harvard University's Center For Health and the Global Environment. Buonocore was not involved with the Duke research, but he previously published a study that evaluated the health implications of implementing renewable energy or energy efficiency measures at six different sites in the United States.
That study also found significant health and economic benefits associated with burning fewer fossil fuels. Air pollution in the United States accounts for approximately 200,000 premature deaths per year, according to a 2013 MIT study.
In the recent Duke work, the researchers wanted to see how implementing policies that would reduce emissions to limit global warming to no more than 2º C would affect health in 2030. First, they calculated that greenhouse gas emissions would have to be reduced 2.7 percent per year, resulting in emissions that were 40 percent below today’s levels by 2030.
Next, they created energy and transportation scenarios that would result in these reductions.
Aside from reducing carbon dioxide, the policies would also result in a reduction of methane, sulfur dioxide, nitrogen oxide, carbon monoxide, and particulate matter.
Surface particulate matter known as PM 2.5 has a particularly negative impact on human health. The researchers found that reductions in this type of pollutant would be greatest over the eastern United States. The upper Midwest, meantime, would see the biggest reductions in nitrogen oxides.
Interestingly, the researchers found that in the near term, the renewable energy scenario would cause a slight warming during the sunnier summer months. The reason for this, Buonocore explains is that renewable energy installations would displace coal-fired power plants, which emit sulfur dioxide. "Those aerosols are white and they reflect sunlight," he says, causing less radiation to reach the earth. Without that pollution blocking the sun, one immediate consequence is that the local temperature will increase in those locations where coal power plants have been displaced. But, he says, "this is a short-term effect." Longer-term the "benefits due to reduced carbon emissions outweigh it."
The Duke team then looked at the impact on premature deaths, using models from previous epidemiological studies. In general, they found that the most lives were saved in the areas with the greatest changes, especially in the reduction of PM 2.5.
Overall, nearly 300,000 premature deaths could be avoided. The authors also noted that there would be additional health benefits that they did not account for, including impact on medical spending, worker productivity, and emergency room visits.
Based on previous analyses "clean energy and transportation policies together could prevent about 29,000 asthma attacks in children under 18 requiring emergency room visits and about 15,000,000 lost adult work days each year," the Duke researchers wrote.
Finally, in order to estimate the cost of their policies, the researchers took into account the cost estimate for implementing the US Clean Power Plan, which achieves only about half of the emission reductions as their energy scenario, as well as an analysis of a plan with similar emissions reductions. They also used a tool called the Social Cost of Atmospheric Release, which includes both climate and air quality benefits, to monetize the health and climate impacts.
Overall, they found that the benefits would outweigh the implementation costs by five- to ten-fold.