BU Today: How much of US methane emissions come from leaky gas lines?

Nathan Phillips: Fossil fuels are the single largest source of methane emissions in the United States, about a third of all human-caused US methane emissions. That’s from everything: old, leaking, abandoned gas and oil wells and coal mines; the whole process chain, from well pad to burner tip in our homes; and the big, high-pressure trunk lines down to the small, low-pressure pipes going into our homes.

In our urban pipeline systems, my colleague Lucy Hutyra [a CAS professor of earth and environment] and her colleagues at Harvard showed that about 2.5 percent of methane has been leaking from our natural gas system in Massachusetts for the better part of the last decade. [That’s] about half of the entire natural gas process chain leak rate. That may not sound like a lot of leaking gas, but it’s about 10 percent of our entire Massachusetts greenhouse gas emissions inventory. At BU, we have a nice one-two punch to look at the leaking natural gas issue from the top down and the bottom up: with Lucy taking a top-down look, while my work has focused on locating the leaking methane sources coming out of the ground.

BU Today: Is the Glasgow pledge a significant step, or must governments provide funding for line repairs to give the pledge teeth?

Nathan Phillips: The Glasgow pledge is a significant step—30 percent reduction in emissions by 2030—and yet the pledge is just that. It’s not binding, as far as I know, and needs to have resources to back it, including funding to address pipeline leaks in places like Boston. And we need to use those resources in the right way.

It’s a positive step, but not a deep enough cut fast enough. Our best science estimates that we need to cut methane by 45 percent by 2030 to keep global warming to 1.5 degrees Celsius.

Research at BU, led by Margaret Hendrick [a former postdoctoral associate with the Institute for Sustainable Energy] showed that a handful of leaks, 7 percent, account for an outsized portion of leaked gas—50 percent, which has enormous policy implications. We can patch leaks cost-effectively while focusing financial resources on transitioning to safer and more climate-beneficial, electric-based heating systems. [Those] are necessary to meet our aggressive Massachusetts climate mandates of 50 percent reduction by 2030 and net-zero emissions by 2050.

BU Today: Many activists doubt the Glasgow summit will arrest carbon dioxide emissions. Will the gathering nevertheless be a success if real methane cuts result?

Nathan Phillips: Right now, there is huge greenwashing
[whitewashing to make something seem more environmentally friendly than it is] happening at COP26, where the fossil fuel industry is floating what I consider to be poor solutions that keep the industry going, when what we need is a swift transition off it. So you’re hearing a lot about carbon capture and sequestration from combusting methane, or hydrogen derived from fossil methane, which has potentially worse carbon emissions than even just burning the methane directly. 

So the pledge of methane reduction is a big deal, but we need to think about reducing methane emissions as part of a strategy to transition off natural gas, rather than as a reason to double down on the fossil energy system of the last century, which cannot meet our climate commitments consistent with climate science. Even if every leak were plugged across the entire process chain.

BU Today: Major methane emitters—Russia, China, India—aren’t taking the pledge. How serious is that setback?

Nathan Phillips: Russia, China, and India not joining is huge, in a bad way for the climate. Not as much for today, but for the coming years. According to the US Energy Information Administration, Russia has the number one gas reserves on the planet, China is number 10, and India is number 23. Moreover, on the consumption side, between them they account for nearly 40 percent of the global population.

There is a massive climate justice issue at play, where countries like India, responsible for a fraction of our global greenhouse emissions, are now facing tough choices about how to transition to the cleanest energy possible. This is why countries like the United States and other countries, who have burned way beyond any concept of a fair share, need to invest in the renewable energy future—both here and in these countries—that the entire globe needs.