For decades, weather satellites have kept a watchful eye on Earth from high above, capturing storms and weather patterns. Now, scientists have found a clever way to "hack" this data for a new purpose: spotting methane emissions.
This innovation has significant implications for the fossil fuel industry, which often struggles to address major methane releases. The new technique, using shortwave infrared observations from NOAA's GOES satellites, can track emissions every five minutes and estimate the total amount released. It can detect large events releasing tens of metric tons of methane per hour.
Here's how it works: satellites analyze how sunlight reflects off Earth to measure methane concentrations. As light passes through methane clouds, its intensity weakens at specific wavelengths. While GOES wasn't designed for methane detection, its sensors include short-wave infrared channels used for observing things like snow cover and wildfires.
This new approach is already proving its worth. Geoanalytics firms and researchers are using it to quantify significant emissions events in North America. In one case, Kayrros SAS estimated a ruptured gas pipeline spewed around 840 metric tons of methane, very close to the operator's reported figure. The impact of this leak was equivalent to annual emissions from 17,000 cars!
The key advantage of this technique is near-continuous, real-time coverage. Existing methane-detection satellites orbit Earth at high speeds, capturing snapshots as they pass by. This limits scientists to estimates of emission rates. GOES, on the other hand, provides a more complete picture.
"GOES can catch short bursts missed by other satellites and track plumes back to their source," explains Daniel Varon, who first proposed the concept. "It can also quantify total release and duration, not just emission rates at a specific time."
This breakthrough comes at a crucial time. Governments face pressure for aggressive action on climate change after record-breaking temperatures. Fossil fuels are the second-largest source of human-caused methane emissions, after agriculture. Reducing leaks and intentional releases from oil, gas, and coal is seen as the fastest and cheapest way to lower temperatures in the short term.
Over 150 countries have joined the Global Methane Pledge, aiming for a 30% reduction by 2030. Major oil and gas companies like Exxon Mobil have also pledged to tackle methane releases.
This innovation is part of a larger trend by young scientists using a diverse range of satellites for methane detection. "It highlights the potential of existing technology to improve detection and tackle the variability of methane emissions," says analyst Maria-Olivia Torcea.
While offering global coverage, existing methane-detection satellites revisit locations every 24 hours or more. Their lower altitude provides higher resolution for identifying smaller leaks, but the infrequent passes limit emission rate estimates.
GOES also has limitations, with coverage primarily focused on the Americas and parts of West Africa. Researchers are exploring if the technique can be applied to similar satellites in Europe and Japan.
The first methane observation using GOES was made by Marc Watine Guiu, a visiting student at Harvard. He collaborated with Varon and others on a paper published in PNAS last December. Their work quantified a methane leak from a gas pipeline in Mexico.
This breakthrough could be a game-changer, empowering regulators to hold fossil fuel companies accountable for methane emissions, which have historically relied on self-reporting. "We can now quantify the total duration and mass of large releases," says Varon. "This technology could be used to audit industry reports."
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