Offshore methane emissions off Angola exceed operator data
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- Analysis shows that the largest methane releases are caused by leaks.
- Older oil and gas platforms account for two thirds of total carbon emissions, despite accounting for only a fraction of oil production.
- Reliable measurement data is essential to understand the true scale of emissions.
- Methane emissions are being recorded in detail for the United Nations Environment Programme (UNEP) as part of the International Methane Emissions Observatory (IMEO).
- Focus: Earth observation, aeronautics, energy, climate change
A new study by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) has found that methane (CH4) emissions from offshore oil and gas platforms off the coast of Angola are lower than previous scientific estimates, but still higher than values reported by operators. Specifically, the study results show that total methane emissions are more than twice as high as those reported by operators. The findings come from the first airborne measurement campaign of methane emissions from offshore facilities in West Africa, conducted by DLR.
"The measurements confirm how important it is to move from estimates to actual data," says Anke Roiger, head of the Atmospheric Trace Species Department at the DLR Institute of Atmospheric Physics. "Only with reliable measurements can we understand the true scale of emissions and make informed decisions to reduce them."
Differences between old and new installations
The analysis shows that the largest methane releases are caused not by flaring, but by leaks – an important finding, as these emissions are often underestimated by operators. The study also identified significant differences between older and newer platforms. Older platforms in shallow waters showed significantly higher emission intensities than newer facilities. The older platforms accounted for two thirds of total carbon emissions, despite accounting for only a fraction of oil production, highlighting the significant mitigation potential of modernising these facilities.
Measurements instead of estimates provide new insights
Several major leaks were also detected even under normal operating conditions, demonstrating that regular measurements are crucial to identifying the precise sources of methane emissions and implementing effective countermeasures. While satellite data provides valuable indications, their limited resolution means they cannot detect every single emission event.
Measurement flights over 57 offshore platforms off the Angolan coast
In 2022, DLR conducted a research flight campaign to measure methane and carbon dioxide emissions from 57 offshore platforms off the Angolan coast. The DLR Falcon 20E research aircraft was equipped with extensive instrumentation and operated under the scientific lead of the DLR Institute of Atmospheric Physics.
Following the campaign, the results were shared with the operators, leading to increased interest in continuous monitoring. The Angolan National Agency of Petroleum, Gas and Biofuels is now considering introducing a national methane reporting system to better track and reduce emissions.
Cooperation and knowledge exchange with the United Nations
The United Nations International Methane Emissions Observatory (IMEO) supported the study to provide accurate, reliable data for the global reduction of methane emissions.
"This research sheds new light on methane emissions from offshore activities in West Africa and underlines the importance of measurements for developing targeted solutions," explains Andreea Calcan, Programme Management Officer at IMEO. "A better data foundation ensures that we can focus our efforts where they will deliver the greatest climate benefit. These scientific findings provide a basis for policymakers and industry to take targeted steps towards a lower-emission future. The IMEO, under the United Nations Environment Programme, stands ready to support its partners in applying these insights to improve monitoring and reduce emissions."
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Greenhouse gas methane
Methane is the second most significant anthropogenic greenhouse gas after carbon dioxide. Because of its high climate impact, the gas is responsible for roughly a quarter to a third of human-caused global warming since pre-industrial times, depending on the calculation model. Alarmingly, the atmospheric methane concentration has been rising at an accelerating rate in recent years, although the reasons for this are not yet fully understood. However, methane breaks down much more quickly in the atmosphere than carbon dioxide. This presents an opportunity to reduce methane concentrations relatively rapidly if decisive action is taken to significantly reduce human-made emissions in the coming years. At the UN Climate Change Conference (COP26) in Glasgow in November 2021, more than 100 countries joined the Global Methane Pledge initiated by the United States and the European Union, committing to reduce global methane emissions by at least 30 percent by 2030 compared to 2020 levels through voluntary measures. Under the agreement, emissions will be recorded in detail according to the standards of the Intergovernmental Panel on Climate Change (IPCC).
Scientific study
Fiehn, Alina, Eckl, Maximilian, Pühl, Magdalena, Bräuer, Tiziana, Gottschaldt, Klaus-Dirk, Aufmhoff, Heinfried, Eirenschmalz, Lisa, Neumann, Gregor, Sakellariou, Felicitas, Sauer, Daniel, Baumann, Robert, De Aguiar Ventura, Guilherme, Cadete, Winne Nayole, Zua, Dário Luciano, Xavier, Manuel, Correia, Paulo, and Roiger, Anke: Airborne quantification of Angolan offshore oil and gas methane emissions, Atmos. Chem. Phys., 25, 15009–15031, https://doi.org/10.5194/acp-25-15009-2025, 2025.