The U.S. carbon footprint looms large as Washington prepares to finally begin, in earnest, a shift away from fossil fuels under a new President promising international action to, "roll back the specter of a warming planet," as Agence France Presse highlighted in its reporting of Obama's inaugural address. Debate is already raging, for example, around whether President Obama will allow California and other states to ratchet up the fuel efficiency improvements automakers must make in the years to come.
But research published yesterday in the New England Journal of Medicine provides a needed reminder that burning less fossil fuels can also directly reduce mortality from air pollution, as reported yesterday by CNN's health desk. (Energywise readers will recall that the network's sci/tech/environment desk is currently unavailable, having been eliminated by CNN last month.)
Tracking mortality data from 1980 to 2000 in 51 cities, the team led by Brigham Young University epidemiologist Clive Arden Pope found that reductions in air pollution over that period added an average of five months to life expectancy. And those living in the cities that cleaned up most, got to spend the most extra time with their grand-kids: the CNN report highlights Pittsburgh, for example, where life expectancy jumped nearly 10 months.
A link between mortality and air pollution -- particularly particulate matter or soot -- is hardly new. It was, for example, a primary driver behind California's Zero Emissions Vehicle program, created years before the state tried to regulate CO2 emissions. And it is part of the reason why a low-carbon fuel standard on the way from California is unlikely to reward drivers switching from gasoline to diesel, which increases soot emissions.
However, this week's study appears to be the first report to show a direct correlation between pollution reduction and longer life.
For balance to the notion that going low-carbon is purifying in all ways, I add the following note of caution from Carnegie Mellon researchers. Their study published in Environmental Science & Technology last month predicts that states that add lots of renewable energy to reduce their carbon footprint could experience an increase in emissions of smog-forming NOx from conventional power plants. That's because the power plants must ramp up and down more than usual to balance out the variable power from wind turbines and solar panels.
This is tough news for air quality regulators, who were anticipating NOx reductions. The Carnegie Mellon team estimates that they could still realize up to half of the NOx reductions anticipated, if the mix of generators providing balancing power is favorable. If not, NOx emissions could quadruple.