Waste sits in piles at ecomaine's southern Maine landfill while a magnet on a crane pulls metals from the processed refuse in the background. Most of Maine’s methane comes from matter decomposing in landfills and releasing natural gas, as well as from agriculture. Credit: Courtesy of ecomaine

The United States has committed to the world that it will reduce emissions of methane, a potent greenhouse gas. As a result, experts say that Maine might see increased interest in certain technologies in the agriculture and waste sectors, but the news is unlikely to accelerate any of the state’s specific climate goals.

At the recent United Nations global climate summit known as Conference of the Parties, or COP, the U.S. joined more than 90 countries in signing a pledge to reduce methane gas emissions by 30 percent, based on 2020 levels, by 2030.

Methane is a particularly potent greenhouse gas. Sean Birkel, research assistant professor and state climatologist at the Climate Change Institute and School of Earth and Climate Sciences at the University of Maine, explained that while methane is less abundant and shorter-lived in the atmosphere, it is estimated to trap about 100 times more heat per molecule compared to its notorious cousin, carbon dioxide.  

“Methane is important because it’s so potent and also because it has a much shorter residence time,” Birkel said. “If that emission can be significantly reduced it would go a long way towards the overall reduction of greenhouse gases and the cumulative impact on temperature.”

Methane is released naturally by wetlands and thawing Arctic permafrost, but the gas is also released by oil and gas production and agriculture. Jonathan Rubin, professor of economics at the University of Maine, said since Maine doesn’t produce natural gas or oil but consumes it, the state may see an impact on the prices of these fossil fuels.

“But price impacts from methane rules to us at the end of the pipeline are probably too small to notice given the day-to-day volatility in the oil and gas markets,” Rubin said. “For oil [and] gas producing states such as Pennsylvania, the story would be different.”

Adam Daigneault, associate professor of forest policy and economics at the University of Maine, said since most of the United States’s implementation strategy to reach the 2030 methane reduction targets involves oil and gas production rather than consumption, the pledges are unlikely to tip the scales when it comes to shifting Maine’s dependence on these fossil fuels — for example, by electrifying the grid and developing infrastructure for electric vehicles.

Most of Maine’s methane comes from matter decomposing in landfills and releasing natural gas, as well as from agriculture. That includes cow burps, but also their manure.

As the U.S. works toward its goals, Daigneault said Maine may experience interest in technologies that cap methane in landfills to use as a substitute for natural gas. It also could include machines such as biogas digesters that use the methane released by cow manure as a renewable gas for heating and cooking, as the Augusta-based Summit Natural Gas of Maine aims to do at a dairy farm in Clinton.

“It’s relatively cost effective in terms of if you can raise the capital,” Daigneault said. “The biggest issue is, we have a lot of small dairy farms so getting every single dairy farm to put in this new system might not be the easiest thing to do even if it’s relatively cost effective.”

Daigneault also pointed to research from Bigelow Laboratory looking at how cows’ diets can be adjusted to release less methane, and said research like that might continue to grow over the next decade.

Still, Daigneault said methane is still a relatively small portion of Maine’s total greenhouse gas emissions. Research shows that only 2 percent of Maine’s greenhouse gas emissions come from agriculture, and Daigneault estimates that only half of that is methane.

“Maine has already taken pledges to reduce greenhouse gases by 80 percent,” Daigneault said. “The agriculture and waste sectors are part of that, but I am not sure it’s going to change anything in terms of the trajectories. It’s a big deal overall in the world. It’s just not a big deal here.”

Birkel said concerted efforts to sharply reduce methane emissions will reduce the amount of warming worldwide. It also will help reduce ground-level ozone pollution, both of which would be to Maine’s benefit. It’s just a matter of whether the U.S. and the rest of the world actually stick to them.