It Wasn’t the Cows After All

Written by Andrew Gunther

While the cattle industry is repeatedly accused of being the main culprit for increased global methane emissions (and a leading cause for climate change), a new study shows that the fertilizer industry is the root cause.

The report by researchers from Cornell and the Environmental Defense Fund, published in Elementa, shows that emissions of methane from the industrial fertilizer industry have been ridiculously underestimated (and, in turns out, based on self-reporting) and the production of ammonia for fertilizer may result in up to 100 times more emissions than previously estimated for this sector. What’s worse is that these newly calculated emission amounts from the industrial fertilizer industry are actually more than the total amount the Environmental Protection Agency (EPA) estimated for all industries to emit across the U.S.

Researchers used a Google Street View car equipped with a high-precision methane sensor to measure the emissions of six fertilizer plants for this study. They drove the car on public roads, downwind from the facilities to record the methane levels in the air. The study reveals an enormous disparity between EPA estimates and actual emissions levels. The team discovered that on average, 0.34 percent of the gas used in the plants is emitted to the atmosphere. Scaling this emission rate from the six plants to the entire industry suggests total annual methane emissions of 28 gigagrams, which is 100 times higher than the fertilizer industry’s self-reported estimate of 0.2 gigagrams per year. In addition, this figure far exceeds the EPA’s estimate that all industrial processes in the United States produce only 8 gigagrams of methane emissions per year.

The fertilizer industry uses natural gas both as the fuel for its operations and as one of the main ingredients for ammonia and urea products (aka the world’s most commonly used nitrogen fertilizers). Since natural gas is largely methane, it has serious potential to be a significant contributor to climate change, and the fact that use of natural gas has grown in recent years has previously raised questions on who’s to blame for rising methane emissions. If it’s been no surprise that natural gas can contribute to climate change, and these facilities rely so heavily on natural gas for production, how could these numbers have been so egregiously underestimated in the first place? It seems this billion-dollar industry made it a point to direct the finger of blame elsewhere.