Why are methane emissions so concerning?
After carbon dioxide, methane is the most common global warming pollutant. It doesn't stay in the atmosphere for very long - only about a decade compared to centuries for carbon dioxide - but it has a huge impact.
Methane's ability to warm the planet is almost 30 times greater than that of carbon dioxide over a 100-year period, and more than 80 times over a 20-year period. You can think of methane as a very effective blanket that traps heat in the atmosphere, warming the planet.
What worries many communities is that methane is also a health problem. It is a precursor to ozone, which can worsen asthma, bronchitis and other lung problems. And in some cases, methane emissions are accompanied by other harmful pollutants, such as benzene, a carcinogen.
In many oil and gas fields, less than 80% of the gas coming out of an underground well is methane; the rest could be dangerous air pollutants that you don't want near your home or school. Yet, until recently, there was very little direct monitoring to detect and stop leaks.
Why are satellites needed to catch methane leaks?
In its natural form, methane is invisible and odorless. You probably wouldn't know there was a huge methane plume next door if you didn't have special instruments to detect it.
Companies have traditionally accounted for methane emissions using a 19th-century method called inventory. Stocks calculate emissions based on reported production at oil and gas wells or the amount of waste going to a landfill, where organic waste generates methane as it decomposes. There is a lot of room for error in this assumption-based accounting; For example, unknown leaks or persistent bleeding are not taken into account.
Until recently, the state of the art in leak detection in oil and gas operations meant that a technician would visit a wellbore approximately every 90 days with a portable infrared camera or gas analyzer. But a major leak can release a huge amount of gas over a period of several days and weeks, or it can occur in locations that are not easily accessible, meaning many of these so-called superemitters go unnoticed.
Remote sensing satellites and aircraft, on the other hand, can survey large areas quickly and routinely. Some of the newer satellites, including those we're launching through the Carbon Mapper Coalition, can zoom in on individual locations at high resolution, allowing us to pinpoint methane superemitters at the specific well pad, compressor station, or portion of a landfill. .
An example of the power of remote sensing can be seen in our recent article in the journal Science. We surveyed 20% of open landfills in the US with aircraft and found that emissions were on average 40% higher than emissions reported to the federal government under assumption-based accounting.
If scientists can monitor regions regularly and consistently from satellites, they can spot superemitter activity and notify the operator quickly, so the operator can find the problem while it's still occurring and fix any leaks.
How do satellites detect methane from space?
Most satellites that can detect methane use some form of spectroscopy.
A typical camera sees the world in three colors: red, green and blue. Developed by NASA's Jet Propulsion Laboratory, the imaging spectrometers we use see the world in nearly 500 colors, including wavelengths beyond the visible spectrum to infrared, which is essential for detecting and measuring greenhouse gases.
Greenhouse gases such as methane and carbon dioxide absorb heat in the infrared wavelengths - each with unique fingerprints. Our technology analyzes sunlight reflected from the Earth's surface to detect those infrared fingerprints of methane and carbon dioxide in the atmosphere.
These characteristics are different from all other gases, so we can image plumes of methane and carbon dioxide to determine the origin of individual superemitters. Once we use spectroscopy to measure the amount of gas in a given plume, we can calculate an emission rate from wind speed data.
What can the new satellites that Carbon Mapper plans to launch do that others haven't done yet?
Each satellite has different and often complementary capabilities. MethaneSat, which the Environmental Defense Fund just launched in March 2024, is like a wide-angle lens that will provide a very accurate and complete picture of methane emissions over large landscapes. Our Carbon Mapper Coalition satellites will complement MethaneSAT by acting as a collection of telephoto lenses. We will be able to zoom in to locate individual methane emitters, like zooming in on a bird nesting in a tree.
Working with our partners at Planet Labs and NASA, we plan to launch the first Carbon Mapper Coalition satellite in 2024, with the goal of expanding the constellation over the coming years to eventually provide daily methane monitoring of high-priority regions across the globe. make the world possible. For example, it is estimated that approximately 90% of methane emissions from fossil fuel production and use come from just 10% of the Earth's surface. That's why we plan to focus the Carbon Mapper Coalition satellites on oil, gas and coal production basins; large urban areas with refineries, wastewater treatment plants and landfills; and major agricultural regions.
How is your monitoring data used?
We expect from experience sharing our aircraft data with facility operators and regulators that much of our future satellite data will be used to guide leak detection and repair efforts.
Many oil and gas companies, landfill operators, and some large farms with methane digesters are motivated to detect leaks because methane is valuable in those cases and can be captured and used. So in addition to the climate and health impacts, methane leaks equate to blowing profits into the atmosphere.
With routine satellite monitoring, we can quickly notify facility owners and operators so they can diagnose and resolve any problems, and we can continue to monitor sites to ensure leaks remain fixed.
Our data can also help alert nearby communities of risks, educate the public, and guide enforcement efforts in cases where companies do not voluntarily repair their leaks. By measuring trends in high-emission methane events over time and across different watersheds, we can also contribute to assessments of whether policies are having the intended effect.
This article is republished from The Conversation, an independent nonprofit organization providing facts and trusted analysis to help you understand our complex world. It was written by: Riley Duren, University of Arizona Read more: Riley Duren is Chief Executive Officer of the nonprofit Carbon Mapper. Carbon Mapper receives funding from a number of philanthropic organizations, as well as grants from the National Aeronautics and Space Administration and the U.S. Environmental Protection Agency.
