Methane, it’s all the rage these days. Or maybe it would be better to say that it’s the outrage, since that’s what this greenhouse gas, consisting of one part carbon and four parts hydrogen, is causing. The alarm and outrage have surged in the wake of the National Oceanic and Atmospheric Administration’s announcement that methane levels spiked last year, despite the pandemic and the associated economic slowdown.
And alarm and outrage often cloud reality, leading to a bunch of confusion and even misinformation. So, the Land Desk is taking it upon itself to try to cut through the murk and get to a clearer notion of what methane is, where it comes from, why it scares folks, and what we can do about it. In order not to overwhelm, we’ll be dividing this up into several dispatches, scattered across the coming weeks (in-between we’ll continue delivering News Roundups, Data Dumps, and other content on non-methane-related topics).
This is the opening salvo, which gives a basic overview of the topic and will serve as the background for future dispatches from the Methane Madness series.
What is methane? Methane, or CH4, is a simple, light hydrocarbon and occurs as an odorless, colorless, combustible, non-toxic gas. Natural gas is made up mostly of methane (along with small quantities of other hydrocarbons). Indeed, natural gas is basically just a brand name or, if you prefer, a greenwash of methane.
Where does it come from? Methane is formed when bacteria decompose organic materials in wetlands, landfills, rice paddies, and many animals’ digestive systems. The natural gas that’s extracted to heat homes and generate power is merely decomposed plankton from ancient seas that has been further altered by heat and pressure and has become trapped in pores in sandstone, limestone, or shale, usually accompanied by oil and ancient water. Coalbed methane is methane formed by decomposition of organic material in prehistoric swamps that has been adsorbed to coal seams. Coalbed methane can build up and explode in coal mines (so it is often vented into the air) and since the 1980s has been extracted commercially via drilling.
How does methane get into the atmosphere? Cows burp, landfills ooze, methane is vented from underground coal mines, natural gas pipelines bust, methane escapes during the drilling process for oil and gas and via leaks in various pieces of equipment, and drillers that are targeting oil often vent or flare (combust) methane that accompanies the oil because it is not profitable to capture it and send it to market. Occasionally methane leaks out of the earth unbidden due to peculiar geologic conditions.
The global atmospheric methane concentration hovered around 700 parts per billion until about two centuries ago, when it started climbing rapidly. The increase accelerated beginning in about 2007, and has now reached nearly 1,900 parts per billion. Clearly, human-related activity is the main culprit.
Why worry? Methane is non-toxic on its own, but it is combustible and if it builds up in an enclosed space it can explode. When methane leaks or is vented from oil and gas operations it is often accompanied by other hydrocarbons, volatile organic compounds, and hydrogen sulfide. Some of these compounds, such as benzene, are known carcinogens, others are ozone precursors, and breathing in hydrogen sulfide can be harmful or fatal. Cut methane emissions and you also reduce emissions of these other harmful compounds.
Yet the cause of most of the consternation these days is that methane is a potent greenhouse gas, with 80 to 100 times the global warming potential of carbon dioxide over the short-term and 20 to 35 times over the long-term.
Why such a big range? When methane is first emitted it traps infrared radiation about 87 times more effectively than carbon dioxide. But over time—about 8 to 12 years—the methane reacts with oxygen to form carbon dioxide and water. So if this is averaged over 20 years the warming potential will be much higher than when it is averaged over 100 years.
Okay, and … ? And that means that if you prevent one ton of methane from entering the atmosphere, it’s the equivalent of avoiding about 87 tons of carbon dioxide emissions when it comes to combating global warming. The Environmental Protection Agency usually uses the 100-year calculation, so it would say that one ton of methane is equivalent to about 25 tons of carbon dioxide.
But wait, I thought natural gas was the “clean” fossil fuel? It is, in a way: When methane is burned to generate power it emits about half as much carbon dioxide as coal per kilowatt hour of power, and virtually none of the mercury, sulfur dioxide, particulates, and other nastiness spewed by coal-burning. But that’s still a lot of carbon dioxide, another greenhouse gas, going into the air. Meanwhile, every part of the natural gas/methane production system is prone to leakage, meaning the more-potent greenhouse gas is oozing into the atmosphere before it reaches the power plant. In theory, if at least 3 percent of the methane used for power production leaks into the atmosphere un-combusted, it will negate natural gas’s climate benefits over coal.
Still, there are important considerations:
Coal mines also emit significant quantities of methane, which is almost always vented directly into the air.
The decrease in power sector carbon dioxide emissions in recent years—along with a clearing of the air of smog in some places—is due to the fact that less coal is being burned to generate electricity, and that’s due in part to the abundance of inexpensive natural gas.
Another caveat: The oil and natural gas industries are almost always lumped together when adding up methane emissions, which makes sense on some levels, since natural gas and oil often occur side-by-side, both come out of the same well side-by-side (along with oodles of water), and most oil companies are also natural gas companies and vice versa.
But there are important distinctions. Drillers that are targeting oil—which right now is far more profitable than natural gas extraction, due to a prolonged price slump for natural gas—tend to see methane as an undesirable byproduct, so they either vent it, meaning that methane is going into the air un-mitigated, or they flare it, thereby converting the methane into carbon dioxide (assuming it burns efficiently, which is rare).
Operators targeting natural gas, on the other hand, have an interest in capturing as much of the natural gas as they possibly can, since that’s their cash crop and every cubic foot of leaked methane is money lost. The natural gas folks still lose a lot of methane, but it’s mostly due to negligence, not because they don’t want the stuff.
That said, it’s unfair to peg all of the methane emissions from the oil and gas sector on the natural gas producers, as McKibben does in the afore-tweeted piece in the New Yorker. McKibben attributes the steep rise in methane concentrations to “… especially, the rapid rise in drilling and fracking for gas.” He then posits: “… we’ve got to stop producing natural gas as quickly as possible, and replace it with renewables that generate neither carbon nor methane.” He may be right about the need to move away from natural gas production, but it would do nothing to stop methane emissions from oil production, which accounts for a major chunk of the emissions from the sector as a whole.
Really, we need to kick gas and oil and coal.
What now? The bad news is that methane emissions worldwide are increasing faster than at any time in the last 40 years. The good news is that methane emissions can be slashed significantly in the short-term—with near-immediate results—without a Herculean effort or major societal changes. Oil and gas companies can plug leaks. Methane from feedlots, dairies, landfills, and coal mines can be captured and used to generate power. Rice paddies can be cultivated differently in order to reduce methane emissions.
We’ll get more into some of these options in upcoming Methane Madness dispatches, as well as tackling methane-emission-reduction policies, debunking methane myths, and exploring innovative emissions reduction efforts. We’ll even take a look at the emerging practice of using methane that would be flared from oil wells to produce power to “mine” for cryptocurrency. But if you don’t subscribe, you may miss out.