Why Methane Matters: The Overlooked Threat to Our Climate

How Outdated Policies & Poor Understanding Are Failing Rhode Island

Yesterday, I joined other scientists in signing a crucial letter to U.S. Secretary of Energy Jennifer Granholm and Secretary of Treasury Janet Yellen. We are sounding the alarm about an urgent problem that many of us in Rhode Island and elsewhere have unsuccessfully tried to bring to the attention of our state governments and congressional representatives: the vastly underestimated impact of natural gas on the global climate.

Natural gas is mostly methane, which is much more than just another greenhouse gas; it's a powerful pollutant that accelerates climate change. The problem lies in outdated legislation from a time when understanding of greenhouse gases was limited. Back then, as the letter states, methane’s potency as a greenhouse gas was widely overlooked.

The problem we face is a variant of the time-honored principle:

You can't manage what you can't measure.

More specifically:

Bad metrics leads to bad policy.

In fact, the situation is even worse. As the letter makes clear, the fossil fuel industry, with support from Republican leaders in the U.S. House of Representatives Committee on Science, Space, and Technology, is defending a flawed metric to game the system. This allows the industry to continue business-as-usual while continuing to ignore the growing climate catastrophe.

Let’s dig a little further into the technical details. Burning coal to produce the power required by industrial civilization generates about twice as much carbon dioxide per unit of energy as burning natural gas. That realization suggested that one could reduce greenhouse gas emissions by switching from coal to natural gas. Cutting the greenhouse gas emissions in half while maintaining energy production is what earned natural gas its reputation as a “cleaner” fuel, as far as global heating is concerned.

Unfortunately, as I’ll explain, this is a perfect example of H. L. Mencken’s Law:

There is always an easy solution to every human problem—neat, plausible, and wrong.

Howarth, Santoro, and Ingraffea explained in a game-changing 2011 paper that the problem is “fugitive methane”—the methane that escapes unburned into the atmosphere. This happens everywhere: at the well, from pipelines, compressor stations, and so on, all the way to the end-user. The crucial issue here is that methane is a much more potent greenhouse gas than carbon dioxide. Howarth and his colleagues found, and subsequent research confirmed, that these methane leaks cancel out the benefits of natural gas’s higher energy content. In fact, for the climate natural gas is worse than coal.

The real challenge for policymakers is that there are several greenhouse gases. The Kyoto Protocol recognizes six main ones, with carbon dioxide and methane being the most relevant for our considerations. Greenhouse gases differ in their global heating impact, and policy decisions invariably involve trade-offs. To assess the total effect of reducing one ill effect while increasing another, a common currency and an associated exchange rate are needed. The common currency is called the carbon dioxide equivalent, and the exchange rate is the global warming potential (GWP).

The GWP measures the climate impact of emitting a kilogram (or any other unit) of a greenhouse gas by comparing it to an identical mass of carbon dioxide—an amount weighing the same. By definition, carbon dioxide has a GWP of 1. For methane the number is much greater than 1. The total obtained by adding up an assortment of emissions weighted by their GWP gives you the carbon dioxide equivalent.

It’s just like calculating people's net worth when they have bank accounts in different currencies, in addition to properties, and other assets. You convert everything to its monetary value, switch to in your preferred currency, and sum up the lot to obtain the desired result.

This is not an exact science, especially when it comes to carbon dioxide equivalents. The complicating issue with methane is that in about a decade half of it breaks down into carbon dioxide, which remains in the atmosphere essentially forever. In other words, methane starts out as a much more potent greenhouse gas than the carbon dioxide it eventually becomes. As a consequence, the climate impact of an amount of methane emitted into the atmosphere changes over time.

The solution to this conundrum is to choose a time horizon, a time over which to average. The hundred-year horizon is commonly used, but a twenty-year horizon aligns better with the realities of climate change. The hundred-year horizon underestimates methane’s impact by a factor of three.

Are you shocked to learn that the fossil fuel industry lobbies Congress for the hundred-year horizon? There you have it: a bad climate metric leading to bad climate policy!

You wouldn’t understand any of this after reading the U.S. Environmental Protection Agency’s Understanding Global Warming Potentials. Indeed, the result of this undoubtedly deliberate confusion are policies that portray methane as a bridge fuel and justify hydrogen production using natural gas as a feedstock—all while ignoring or underestimating the impact of the methane that escapes unburned into the atmosphere.

All of the above is not just a federal issue. It directly applies to Rhode island, as I wrote in my previous post in reference to the 2021 Act on Climate:

If the Energy Information Administration is correct, Rhode Island generated 83% of its electricity from natural gas in both 2022 and 2024. This indicates that Rhode Island is making no progress whatsoever on the path that Speaker Shekarchi so proudly announced in 2021.

I was particularly pleased to see the letter stress the importance of the precautionary principle, which is the notion that in the case of uncertainty, one should err on the side of caution. This principle is usually ignored in U.S. law and policy making:

Finally, we write to urge you to apply the precautionary principle when applying greenhouse gas emissions analysis to far-reaching decisions that could shape energy production and consumption for years to come. We are already at considerable risk of overshooting global and U.S. commitments to reduce greenhouse gasses and stabilize global greenhouse gas concentrations in the atmosphere. Comparative analysis of new gas supplies to other fuels are only as good as our vision of the future energy pathways that we need to achieve. International Energy Agency’s World Energy Outlook 2023 envisions a 50% reduction in global gas supply for its net-zero pathway.

That, in a nutshell, summarizes the letter I signed on to. It’s up to all of us to push for better policies—ones that recognize the true impact of methane. Our future depends on it!

Follow this link if you are or know a scientist who wants to sign on.