Gas flaring, the controlled burning of excess gas at industrial facilities, exists primarily as a safety mechanism. Oil refineries, chemical plants, and drilling sites produce gas that can build to dangerous pressures inside equipment. Burning it off through a flare stack is far safer than letting it accumulate, and far less harmful to the climate than releasing unburned methane directly into the atmosphere. Flaring is necessary because, in many situations, there is simply no safe or economical alternative for disposing of excess gas in real time.
Flaring as Emergency Pressure Relief
The most critical reason flaring exists is to prevent explosions. The majority of chemical plants and refineries have flare systems designed specifically to handle emergency process upsets, moments when equipment malfunctions, cooling systems fail, or an entire unit needs to depressurize quickly. During these events, large volumes of gas must be released rapidly to keep pressure from exceeding what pipes, tanks, and vessels can withstand. A flare stack gives that gas somewhere to go and burns it safely in the open air rather than letting it pool at ground level where it could find an ignition source near workers or equipment.
The engineering behind a flare system reflects how seriously the risk is taken. Before gas reaches the flare tip, it passes through a knockout drum that removes any liquids. For emergency scenarios like a total loss of cooling water, these drums are sized for worst-case volumes and can be enormous. A liquid seal sits between the flare stack and the upstream piping, serving two purposes: it maintains positive pressure on the system and acts as a barrier against explosive shock waves traveling back down the stack. The flare is also elevated high above ground level to keep the open flame far from process units, personnel, and anything else that could ignite.
Gas flow to the flare tip has to be carefully controlled at all times. If flow drops too low, air can creep into the flare header and mix with residual gas, creating an explosive mixture inside the system itself. Pilot flames keep the flare lit continuously so that any gas arriving at the tip ignites immediately rather than accumulating.
Why Burning Is Better Than Venting
If the goal is just to get rid of excess gas, you might wonder why facilities don’t simply vent it into the atmosphere without burning it. The answer comes down to chemistry. Natural gas is mostly methane, and methane is an exceptionally potent greenhouse gas. Over a 100-year period, one ton of methane traps 27 to 30 times more heat than one ton of carbon dioxide. Methane lasts about a decade in the atmosphere before breaking down, which is far shorter than CO2, but during that time it absorbs vastly more energy.
When a flare burns methane, it converts it primarily into carbon dioxide and water vapor. A well-functioning flare destroys about 98% of the methane that passes through it. That conversion trades a powerful short-term warming agent for a weaker one. It’s not harmless, but it’s significantly less damaging than releasing raw methane. This is the core environmental logic behind flaring: when you cannot capture the gas, burning it is the next best option.
Real-World Efficiency Falls Short
The 98% destruction rate applies to flares that are lit and operating properly. In practice, the picture is messier. A University of Michigan study examining real-world flare performance across multiple regions found that flares effectively destroy only about 91% of methane on average. The gap comes from two roughly equal sources: flares that are completely unlit (meaning gas passes through without being burned at all) and flares that are lit but burning inefficiently. Most individual flares do perform close to the expected 98%, but the ones that malfunction drag the average down considerably.
This distinction matters because climate models and regulatory estimates typically assume flares are always lit and always efficient. A 7-percentage-point gap between assumed and actual destruction rates means substantially more methane is escaping into the atmosphere than official numbers suggest.
The Scale of Global Flaring
Global gas flaring reached 148 billion cubic meters in 2023, a 7% increase from the previous year and the highest level since 2019. That figure comes from the World Bank’s Global Gas Flaring Tracker, which relies on satellite observations from an instrument called VIIRS that detects the heat signatures of flares from orbit.
Even that number is likely an undercount. A 2024 analysis comparing satellite estimates with industry-reported data in western Canada found that companies reported 2.2 times more flaring than the satellite detected, across more than 14 times as many sites. About 76% of the discrepancy came from small or intermittent flares with flow rates too low for the satellite to pick up. The remaining 24% involved enclosed combustion devices whose shielded flames don’t produce a visible heat signature from space. Similar detection gaps likely exist in other regions with comparable flare sizes, meaning the true global total could be significantly higher than 148 billion cubic meters.
Routine Flaring vs. Emergency Flaring
Not all flaring serves the same purpose, and this distinction is central to the policy debate. Emergency flaring is the safety-critical kind: pressure relief during equipment failures, startups, shutdowns, and process upsets. This type of flaring is broadly accepted as necessary because the alternative is risking catastrophic equipment failure or explosions.
Routine flaring is different. It happens at oil production sites where natural gas comes up alongside the oil but there’s no pipeline, processing plant, or local market to send it to. Rather than cap the well or invest in gas capture infrastructure, operators burn the gas continuously as a cost of doing business. This is the type of flaring that draws the most criticism, because it represents wasted energy and avoidable emissions. The World Bank’s Zero Routine Flaring by 2030 initiative, launched in 2015, commits participating governments and oil companies to eliminate routine flaring by the end of this decade through better regulation, technology deployment, and financing arrangements.
What Flaring Releases Into the Air
Even when a flare is burning efficiently, it doesn’t produce only CO2 and water. Incomplete combustion generates volatile organic compounds, polycyclic aromatic hydrocarbons, nitrogen oxides, and fine particulate matter. Communities near oil and gas operations can be exposed to these pollutants from flaring as well as from other site activities like produced water storage and diesel equipment. For people living near large or numerous flare sites, air quality is a genuine health concern, particularly from compounds like benzene that are known carcinogens even at low concentrations.
Alternatives That Reduce the Need to Flare
Several technologies exist to capture gas that would otherwise be flared, particularly at smaller or more remote production sites where building a full pipeline isn’t practical. Gas processing skids can strip out valuable liquids like propane and butane on-site, making the remaining gas easier to transport or use locally. Dual-fuel systems allow drilling and hydraulic fracturing equipment to run on the associated gas instead of diesel, turning a waste product into fuel. Membrane-based separation systems use hybrid combinations of membranes and chillers to process gas into usable products right at the wellhead.
The challenge is economics. At remote sites producing relatively small volumes of gas, the cost of installing capture equipment can exceed the value of the gas itself, especially when oil prices are high and gas prices are low. This is why routine flaring persists despite available technology. Regulations that put a price on flared gas, or that simply ban routine flaring after a set deadline, change the math and push operators toward capture solutions they might not adopt voluntarily.