Drunk off fuel
Ethanol has been widely trumpeted as a viable alternative to fossil fuels, at least until a couple years ago when a food scarcity scare had people suddenly questioning whether food and energy should be competitors for the same land.
But here’s another thing that needs considering. One in three molecules of ethanol in the atmosphere is now human-added. No one has questioned the impacts of pumping so much ethanol a year into the air. Until now.
Research led by Princeton University has come up with the first analysis of the sources of ethanol in the atmosphere and how it’s moving around.
In a paper published last month in the journal Atmospheric Chemistry and Physics, researchers estimate that about nine million tons a year come from terrestrial plants, another five million tons from anthropogenic sources (industry and biofuels), and another half a million ton from biomass burning.
Human sources aren’t the highest contributors, but they sure are significant. The study pointed to several areas — the North Pacific off the coast of Asia and New England — where humans are the largest sources of ethanol.
Plants emit ethanol from their leaves and stems and tend to do it more so when under stress from floods, droughts, or pollution. Presumably, the extra ethanol they put into the air under such conditions could be another indirect effect of humans.
The impacts of all the extra ethanol are not innocuous. The combustion of ethanol releases volatile organic compounds that are toxic. Ethanol also contributes to ozone pollution.
Ethanol probably still is cleaner burning than dirty gasoline. But it’s not an innocent player in the search for the perfect fuel.