There was little to mark the pipe as a threat to the planet: A skinny gray chimney the same color as the clouds, looming lankily above a gas storage facility at an industrial site in northern Italy. It did not appear to be in use.

Then James Turitto took out his camera. 

Seen through the lens of the $100,000 (€95,567) infrared device calibrated to pick up planet-heating gases, the pipe was belching a stream of methane into the sky. Turitto, who hunts fugitive emissions for the environmental nonprofit Clean Air Task Force (CATF), has seen hundreds of similar leaks at oil and gas sites across Europe that otherwise go unnoticed. The pipe had already been leaking methane when Turitto visited eight months earlier.

Experts say invisible clouds of methane billowing out of fossil fuel facilities like this one are some of the easiest emissions to avoid. Fixing them is no replacement for cutting carbon dioxide pollution, but it represents one of the cheapest tools humanity has to keep global warming in check over the coming decades.

"We're talking about plumbing, literally," said Turitto.

Why does methane matter for the climate?

Methane is a gas responsible for about a quarter of global warming since the Industrial Revolution. While it doesn't last as long in the atmosphere as CO2, it is 80 times more powerful over a 20-year period.

In 2015 world leaders pledged to keep global warming well below 2 degrees Celsius (3.6 Fahrenheit) — and ideally 1.5 C — by the end of the century in a belated bid to stop weather extremes like storms and heat waves spiraling further out of control.

But that lower temperature threshold looks likely to be crossed within the next couple of decades, according to scenarios assessed by the UN's Intergovernmental Panel on Climate Change in August. Even if governments were to bring temperatures back down later in the century, some ecosystems would not survive, the scientists found in a follow-up report in February.

Experts say cutting methane could play an outsize role in preventing humanity from overshooting its temperature targets because the gas is so powerful in the short term. A report by the United Nations Environment Program (UNEP) last year found that nearly halving methane emissions this decade will avoid almost 0.3 C of global warming by the 2040s. "Fast and ambitious methane mitigation is one of the best strategies available today," said UNEP Executive Director Inger Andersen. 

Where does methane come from?

Global methane pollution soared to record levels in 2021, according to data published in April by the National Oceanic and Atmospheric Administration of the US government. "If this trend continues it will put serious challenges to our capability to meet climate goals — even if we have very fast, rapid CO2 reduction," said Yuzhong Zhang, an atmospheric scientist at Westlake University in China.

Some of the rise in methane is due to natural releases. But humans have also created three powerful sources of the gas.

About 40% of humanity's methane emissions come from farms, where animals like cattle and sheep belch out huge quantities of the gas as they digest food. Another 20% comes from landfills, where methane is made as bacteria break down organic matter without oxygen. Just over one-third comes from fossil fuel facilities.

Methane is the main component in fossil gas — also known as natural gas — and it pours out when fuels are extracted, processed, moved and stored. Because methane emissions from coal are hard to find and fix, scientists have focused their efforts on oil and gas.

"It's complete low hanging fruit, frankly," said Dagmar Droogsma, from the Environmental Defense Fund, a group that has documented methane emissions across the US. The solutions are so cheap that "even from a commercial point of view it's a no-brainer." 

How does methane leak from oil and gas facilities?

There are three ways methane is released into the atmosphere from oil and gas facilities. There are simple leaks, which could happen because of a loose screw or a rusty piece of equipment. Then there are practices like venting, where methane is intentionally let out into the atmosphere. This is often done to reduce pressure in a pipe — for instance, during maintenance work — but is rarely needed.

The third source is flaring, when companies burn the methane coming out of the vent. Flaring fossil gas turns methane into CO2, which is less harmful in the short-term despite its longer-lasting effect on the planet. But it is often done so poorly that raw methane still escapes into the atmosphere. 

In 2021, the CATF documented methane emissions at 180 of the 250 oil and gas sites it visited across Europe.

During a visit to two gas storage facilities in northern Italy in February, DW accompanied Turitto as he found methane leaking from three sites in a single morning. The leaks came from pieces of equipment that ranged in size from tiny valves to tall vents.

"Some of the sources can certainly be fixed pretty easily," said Turitto. "We were just looking at a valve that looked like it really could just be tightened. [For] other stuff, fixing and repairing them might be a little more complex."

The operator Snam, a privately owned gas company that used to be a subsidiary of Italian energy giant ENI, did not respond to a request for comment.

How can we find leaks?

The International Energy Agency (IEA) estimates the world's methane emissions from the power sector — coal, oil, gas and biomass — are about 70% higher than countries report in their official data. As well as methane hunters armed with special cameras, scientists with satellites are spotting methane clouds that are well above what companies and governments say they're releasing.

A study published in the journal Science in February analyzed satellite images of hundreds of methane releases between 2019 and 2020. The scientists found about 10% of the industry's methane emissions come from gigantic releases that happen rarely — and are difficult to detect through occasional site visits with infrared cameras — but release enormous quantities of gas into the atmosphere.

"In the field we can see all these leaky defective little materials... but you don't see the key players," said Thomas Lauvaux, a climate scientist at the French National Center for Scientific Research and lead author of the study. A giant burst of methane intentionally released "is worth a thousand tiny leaks." 

How can we cut methane emissions?

Fossil fuel companies could slash methane emissions by 75% using technologies that already exist, according to the IEA. That includes regular inspections to find and fix leaks, as well as a ban on practices like routine flaring and venting. Companies could instead capture gas using compressor devices, and flare only the gas that needs to be burned during emergency repair work.

With gas prices inflated by Russia's invasion of Ukraine, experts expect most of the cuts to come at zero cost to the companies, who could instead take gas they currently waste and sell it on for use in industry. "When you're venting gas, you're losing a lot of gas," said Turitto. "That's a lot of money."

Some governments are taking steps to regulate the industry. At the COP26 climate summit in November 2021, more than 100 countries pledged to cut emissions by 30% from 2020 levels by 2030. The European Union plans to introduce new requirements for measuring and reporting methane emissions, as well as spotting and plugging leaks. It has also proposed a ban on venting and flaring.  

But the plans have come under criticism for not considering imported fuels. Groups like the CATF are calling for an import standard to ensure oil and gas extracted abroad comes from facilities and pipelines that are plugging their methane leaks.

Edited by: Jennifer Collins