In and around Washington DC, a dedicated group of volunteers and activists has been taking to the streets, armed with sophisticated gas sensors to measure methane levels in the air. These handheld devices, resembling walkie-talkies, help the researchers detect the presence of methane and other harmful gases, transforming the invisible threat of methane into concrete numbers displayed on a screen. The findings are concerning: in a 25-hour period, researchers found 13 outdoor methane leaks at concentrations exceeding the lower explosive limit, along with leaks within homes.
Methane is not only a health hazard but also a potent greenhouse gas. Despite its shorter lifespan in the atmosphere compared to carbon dioxide (CO2), methane is far more efficient at trapping heat and is responsible for approximately a quarter of the global temperature rise since industrialisation. The sources of methane emissions are diverse, including fossil fuels, agriculture, and waste. However, detecting methane is no simple task, and the need to identify and address leaks is more crucial than ever.
One of the key concerns with methane is its impact on human health. Methane, when combined with other gases such as nitrogen oxide from gas stoves, is linked to higher asthma risks, particularly in children. Djamila Bah, a healthcare worker and tenant leader for the community organisation Action in Montgomery, has highlighted the alarming rates of asthma in the homes tested by the group. According to Ms Bah, one in three children in the homes tested suffer from asthma, a statistic that is both “heartbreaking and alarming.”
While methane’s impact on health is significant, its contribution to climate change is even more critical. The gas’s high heat-trapping ability makes it a major contributor to global warming, with methane emissions having a more immediate and potent effect than CO2 in the short term. As such, detecting and reducing methane emissions is essential in the fight against climate change.
Monitoring methane emissions, however, comes with its own set of challenges. Methane can be detected using handheld sensors, infrared cameras, or by employing ground-based and aerial technologies, such as vehicle-mounted devices or drones. While each technology has its merits, there is no perfect solution. The cost of monitoring technologies often dictates their scale and effectiveness, especially when it comes to large-scale monitoring of thousands of facilities.
Andreea Calcan, a programme management officer at the International Methane Emissions Observatory (IMEO), a UN initiative, acknowledges the difficulties involved in methane detection. While affordable sensors have become more accessible in the past decade, she stresses that there are trade-offs between technology costs and the scale of emissions analysis. Nonetheless, Calcan believes that tackling both small leakages and large-scale, high-emitting events is crucial.
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At a broader level, satellites have proven useful for pinpointing “super-emitters,” large-scale methane releases, such as those from oil and gas operations. Satellites can also detect smaller, more dispersed emissions, such as those from cattle farms. However, detecting methane with satellites has its limitations, particularly in areas with challenging terrain, such as snow-covered oil fields or heavily vegetated regions. Low light conditions and offshore areas present additional challenges for accurate methane detection.
To address these challenges, new technologies are being developed. One such advancement is the Tanager-1 satellite, launched by the Carbon Mapper organisation in collaboration with NASA’s Jet Propulsion Laboratory and Planet Labs. The high-resolution Tanager-1 is designed to overcome some of the limitations of previous satellites, offering better sensitivity and faster detection of methane emissions. The satellite can “sneak peeks” through gaps in clouds or forest cover, enabling it to detect methane from specific sources, such as oil wellheads, even when surrounded by other infrastructure.
Riley Duren, CEO of Carbon Mapper, believes that the high resolution and precision of the Tanager-1 will enable the identification of methane emissions from super-emitters with greater accuracy. This, in turn, will help hold responsible parties accountable for their emissions. As Mr Duren notes, “What was previously unseeable is now visible,” and these advancements in satellite technology are enabling society to learn more about its true methane footprint.
Despite the progress in satellite technologies, translating the data into effective action remains a challenge. The Methane Alert and Response System (MARS), which uses satellite data to detect methane plumes, has issued over 1,200 alerts for major methane leaks since its launch. However, only 1% of these alerts have led to direct responses. Still, Itziar Irakulis Loitxate, remote sensing lead for the International Methane Emissions Observatory, remains optimistic. She believes that the percentage of responses will increase as communication and collaboration between stakeholders improve.
At the community level, residents in the Washington DC area have found power in using their own air pollution readings to counter misinformation and raise awareness about methane leaks. Joelle Novey of Interfaith Power and Light emphasises the importance of local involvement: “Now that we know better, we can do better.”
The increasing sophistication of methane detection technologies, from handheld sensors to satellites, is undoubtedly a step forward in addressing this urgent issue. As society continues to learn more about methane emissions, it is clear that the need for effective monitoring and decisive action is more pressing than ever.
