Anthony J. Marchese, Colorado State University and Dan Zimmerle, Colorado State University

Natural gas is displacing coal, which could help fight climate change because burning it produces fewer carbon emissions. But producing and transporting natural gas releases methane, a greenhouse gas that also contributes to climate change. How big is the methane problem?

For the past five years, our research teams at Colorado State University have made thousands of methane emissions measurements at more than 700 separate facilities in the production, gathering, processing, transmission and storage segments of the natural gas supply chain.

This experience has given us a unique perspective regarding the major sources of methane emissions from natural gas and the challenges the industry faces in terms of detecting and reducing, if not eliminating, them.

Our work, along with numerous other research projects, was recently folded into a new study published in the journal Science. This comprehensive snapshot suggests that methane emissions from oil and gas operations are much higher than current EPA estimates.

What’s wrong with methane

One way to quantify the magnitude of the methane leakage is to divide the amount of methane emitted each year by the total amount of methane pumped out of the ground each year from natural gas and oil wells. The EPA currently estimates this methane leak rate to be 1.4 percent. That is, for every cubic foot of natural gas drawn from underground reservoirs, 1.4 percent of it is lost into the atmosphere.

This study synthesized the results from a five-year series of 16 studies coordinated by environmental advocacy group Environmental Defense Fund (EDF), which involved more than 140 researchers from over 40 institutions and 50 natural gas companies.

The effort brought together scholars based at universities, think tanks and the industry itself to make the most accurate estimate possible of the total amount of methane emitted from all U.S. oil and gas operations. It integrated data from a multitude of recent studies with measurements made on the ground and from the air.

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All told, based on the results of the new study, the U.S. oil and gas industry is leaking 13 million metric tons of methane each year, which means the methane leak rate is 2.3 percent. This 60 percent difference between our new estimate and the EPA’s current one can have profound climate consequences.

Methane is a highly potent greenhouse gas, with more than 80 times the climate warming impact of carbon dioxide over the first 20 years after it is released.

An earlier EDF study showed that a methane leak rate of greater than 3 percent would result in no immediate climate benefits from retiring coal-fired power plants in favor of natural gas power plants.

That means even with a 2.3 percent leakage rate, the growing share of U.S. electricity powered by natural gas is doing something to slow the pace of climate change. However, these climate benefits could be far greater.

Also, at a methane leakage rate of 2.3 percent, many other uses of natural gas besides generating electricity are conclusively detrimental for the climate. For example, EDF found that replacing the diesel used in most trucks or the gasoline consumed by most cars with natural gas would require a leakage rate of less than 1.4 percent before there would be any immediate climate benefit.

What’s more, some scientists believe that the leakage rate could be even higher than this new estimate.

What causes these leaks

Perhaps you’ve never contemplated the long journey that natural gas travels before you can ignite the burners on the gas stove in your kitchen.

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But on top of the 500,000 natural gas wells operating in the U.S. today, there are 2 million miles of pipes and millions of valves, fittings, tanks, compressors and other components operating 24 hours per day, seven days a week to deliver natural gas to your home.

That natural gas that you burn when you whip up a batch of pancakes may have traveled 1,000 miles or more as it wended through this complicated network. Along the way, there were ample opportunities for some of it to leak out into the atmosphere.

Natural gas leaks can be accidental, caused by malfunctioning equipment, but a lot of natural gas is also released intentionally to perform process operations such as opening and closing valves. In addition, the tens of thousands of compressors that increase the pressure and pump the gas along through the network are powered by engines that burn natural gas and their exhaust contains some unburned natural gas.

Since the natural gas delivered to your home is 85 to 95 percent methane, natural gas leaks are predominantly methane. While methane poses the greatest threat to the climate because of its greenhouse gas potency, natural gas contains other hydrocarbons that can degrade regional air quality and are bad for human health.

Inventory tallies vs. aircraft surveillance

The EPA Greenhouse Gas Inventory is done in a way experts like us call a “bottom-up” approach. It entails tallying up all of the nation’s natural gas equipment – from household gas meters to wellpads – and estimating an annualized average emission rate for every category and adding it all up.

There are two challenges to this approach. First, there are no accurate equipment records for many of these categories. Second, when components operate improperly or fail, emissions balloon, making it hard to develop an accurate and meaningful annualized emission rate for each source.

“Top-down” approaches, typically requiring aircraft, are the alternative. They measure methane concentrations upwind and downwind of large geographic areas. But this approach has its own shortcomings.

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First, it captures all methane emissions, rather than just the emissions tied to natural gas operations – including the methane from landfills, cows and even the leaves rotting in your backyard. Second, these one-time snapshots may get distorted depending on what’s going on while planes fly around capturing methane data.

Historically, top-down approaches estimate emissions that are about twice bottom-up estimates. Some regional top-down methane leak rate estimates have been as high as 8 percent while some bottom-up estimates have been as low as 1 percent.

More recent work, including the Science study, have performed coordinated campaigns in which the on-the-ground and aircraft measurements are made concurrently, while carefully modeling emission events.

Helpful gadgets and sound policy

On a sunny morning in October 2013, our research team pulled up to a natural gas gathering compressor station in Texas. Using an US$80,000 infrared camera, we immediately located an extraordinarily large leak of colorless, odorless methane that was invisible to the operator who quickly isolated and fixed the problem.

We then witnessed the methane emissions decline tenfold – the facility leak rate fell from 9.8 percent to 0.7 percent before our eyes.

It is not economically feasible, of course, to equip all natural gas workers with $80,000 cameras, or to hire the drivers required to monitor every wellpad on a daily basis when there are 40,000 oil and gas wells in Weld County, Colorado, alone.

But new technologies can make a difference. Our team at Colorado State University is working with the Department of Energy to evaluate gadgetry that will rapidly detect methane emissions. Some of these devices can be deployed today, including inexpensive sensors that can be monitored remotely.

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Technology alone won’t solve the problem, however. We believe that slashing the nation’s methane leak rate will require a collaborative effort between industry and government. And based on our experience in Colorado, which has developed some of the nation’s strictest methane emissions regulations, we find that best practices become standard practices with strong regulations.

We believe that the Trump administration’s efforts to roll back regulations, without regard to whether they are working or not, will not only have profound climate impacts. They will also jeopardize the health and safety of all Americans while undercutting efforts by the natural gas industry to cut back on the pollution it produces.

Anthony J. Marchese, Associate Dean for Academic and Student Affairs, Walter Scott, Jr. College of Engineering; Director, Engines and Energy Conversion Laboratory; Professor, Department of Mechanical Engineering, Colorado State University and Dan Zimmerle, Senior Research Associate and Director of METEC, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Richard B. (Ricky) Rood, University of Michigan

An Arctic blast hitting the central and eastern U.S. in early January 2025 has been creating fiercely cold conditions in many places. Parts of North Dakota dipped to more than 20 degrees below zero, and people as far south as Texas woke up to temperatures in the teens. A snow and ice storm across the middle of the country added to the winter chill.

Forecasters warned that temperatures could be “10 to more than 30 degrees below normal” across much of the eastern two-thirds of the country during the first full week of the year.

But what does “normal” actually mean?

While temperature forecasts are important to help people stay safe, the comparison to “normal” can be quite misleading. That’s because what qualifies as normal in forecasts has been changing rapidly over the years as the planet warms.

Defining normal

One of the most used standards for defining a science-based “normal” is a 30-year average of temperature and precipitation. Every 10 years, the National Center for Environmental Information updates these “normals,” most recently in 2021. The current span considered “normal” is 1991-2020. Five years ago, it was 1981-2010.

But temperatures have been rising over the past century, and the trend has accelerated since about 1980. This warming is fueled by the mining and burning of fossil fuels that increase carbon dioxide and methane in the atmosphere. These greenhouse gases trap heat close to the planet’s surface, leading to increasing temperature.

Because global temperatures are warming, what’s considered normal is warming, too.

So, when a 2025 cold snap is reported as the difference between the actual temperature and “normal,” it will appear to be colder and more extreme than if it were compared to an earlier 30-year average.

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Thirty years is a significant portion of a human life. For people under age 40 or so, the use of the most recent averaging span might fit with what they have experienced.

But it doesn’t speak to how much the Earth has warmed.

How cold snaps today compare to the past

To see how today’s cold snaps – or today’s warming – compare to a time before global warming began to accelerate, NASA scientists use 1951-1980 as a baseline.

The reason becomes evident when you compare maps.

For example, January 1994 was brutally cold east of the Rocky Mountains. If we compare those 1994 temperatures to today’s “normal” – the 1991-2020 period – the U.S. looks a lot like maps of early January 2025’s temperatures: Large parts of the Midwest and eastern U.S. were more than 7 degrees Fahrenheit (4 degrees Celsius) below “normal,” and some areas were much colder.

But if we compare January 1994 to the 1951-1980 baseline instead, that cold spot in the eastern U.S. isn’t quite as large or extreme.

Where the temperatures in some parts of the country in January 1994 approached 14.2 F (7.9 C) colder than normal when compared to the 1991-2020 average, they only approached 12.4 F (6.9 C) colder than the 1951-1980 average.

As a measure of a changing climate, updating the average 30-year baseline every decade makes warming appear smaller than it is, and it makes cold snaps seem more extreme.

Conditions for heavy lake-effect snow

The U.S. will continue to see cold air outbreaks in winter, but as the Arctic and the rest of the planet warm, the most frigid temperatures of the past will become less common.

That warming trend helps set up a remarkable situation in the Great Lakes that we’re seeing in January 2025: heavy lake-effect snow across a large area.

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As cold Arctic air encroached from the north in January, it encountered a Great Lakes basin where the water temperature was still above 40 F (4.4 C) in many places. Ice covered less than 2% of the lakes’ surface on Jan. 4.

That cold dry air over warmer open water causes evaporation, providing moisture for lake-effect snow. Parts of New York and Ohio along the lakes saw well over a foot of snow in the span of a few days.

The accumulation of heat in the Great Lakes, observed year after year, is leading to fundamental changes in winter weather and the winter economy in the states bordering the lakes.

It’s also a reminder of the persistent and growing presence of global warming, even in the midst of a cold air outbreak.

Richard B. (Ricky) Rood, Professor Emeritus of Climate and Space Sciences and Engineering, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Patrick Megonigal, Smithsonian Institution

Firefighters battling the deadly wildfires that raced through the Los Angeles area in January 2025 have been hampered by a limited supply of freshwater. So, when the winds are calm enough, skilled pilots flying planes aptly named Super Scoopers are skimming off 1,500 gallons of seawater at a time and dumping it with high precision on the fires.

Using seawater to fight fires can sound like a simple solution – the Pacific Ocean has a seemingly endless supply of water. In emergencies like Southern California is facing, it’s often the only quick solution, though the operation can be risky amid ocean swells.

But seawater also has downsides.

Saltwater corrodes firefighting equipment and may harm ecosystems, especially those like the chaparral shrublands around Los Angeles that aren’t normally exposed to seawater. Gardeners know that small amounts of salt – added, say, as fertilizer – does not harm plants, but excessive salts can stress and kill plants.

While the consequences of adding seawater to ecosystems are not yet well understood, we can gain insights on what to expect by considering the effects of sea-level rise.

A seawater experiment in a coastal forest

As an ecosystem ecologist at the Smithsonian Environmental Research Center, I lead a novel experiment called TEMPEST that was designed to understand how and why historically salt-free coastal forests react to their first exposures to salty water.

Sea-level rise has increased by an average of about 8 inches globally over the past century, and that water has pushed salty water into U.S. forests, farms and neighborhoods that had previously known only freshwater. As the rate of sea-level rise accelerates, storms push seawater ever farther onto the dry land, eventually killing trees and creating ghost forests, a result of climate change that is widespread in the U.S. and globally.

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In our TEMPEST test plots, we pump salty water from the nearby Chesapeake Bay into tanks, then sprinkle it on the forest soil surface fast enough to saturate the soil for about 10 hours at a time. This simulates a surge of salty water during a big storm.

Our coastal forest showed little effect from the first 10-hour exposure to salty water in June 2022 and grew normally for the rest of the year. We increased the exposure to 20 hours in June 2023, and the forest still appeared mostly unfazed, although the tulip poplar trees were drawing water from the soil more slowly, which may be an early warning signal.

Things changed after a 30-hour exposure in June 2024. The leaves of tulip poplar in the forests started to brown in mid-August, several weeks earlier than normal. By mid-September the forest canopy was bare, as if winter had set in. These changes did not occur in a nearby plot that we treated the same way, but with freshwater rather than seawater.

The initial resilience of our forest can be explained in part by the relatively low amount of salt in the water in this estuary, where water from freshwater rivers and a salty ocean mix. Rain that fell after the experiments in 2022 and 2023 washed salts out of the soil.

But a major drought followed the 2024 experiment, so salts lingered in the soil then. The trees’ longer exposure to salty soils after our 2024 experiment may have exceeded their ability to tolerate these conditions.

Seawater being dumped on the Southern California fires is full-strength, salty ocean water. And conditions there have been very dry, particularly compared with our East Coast forest plot.

Changes evident in the ground

Our research group is still trying to understand all the factors that limit the forest’s tolerance to salty water, and how our results apply to other ecosystems such as those in the Los Angeles area.

Tree leaves turning from green to brown well before fall was a surprise, but there were other surprises hidden in the soil below our feet.

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Rainwater percolating through the soil is normally clear, but about a month after the first and only 10-hour exposure to salty water in 2022, the soil water turned brown and stayed that way for two years. The brown color comes from carbon-based compounds leached from dead plant material. It’s a process similar to making tea.

Our lab experiments suggest that salt was causing clay and other particles to disperse and move about in the soil. Such changes in soil chemistry and structure can persist for many years.

Sea-level rise is increasing coastal exposure

While ocean water can help fight fires, there are reasons fire officials prefer freshwater sources – provided freshwater is available.

U.S. coastlines, meanwhile, are facing more extensive and frequent saltwater exposure as rising global temperatures accelerate sea-level rise that drowns forests, fields and farms, with unknown risks for coastal landscapes.

Patrick Megonigal, Associate Director of Research, Smithsonian Environmental Research Center, Smithsonian Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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