Science

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Methane (CH4) and carbon dioxide (CO2) are the two dominant anthropogenic (human generated) climate-forcing agents. Additionally, CH4 is relevant to air-quality science and applications: CH4 is a precursor for tropospheric ozone and is strongly linked with co-emitted reactive trace gases that can impact human health. The figures here from the Global Carbon Project summarize the global CH4 and CO2 “budgets”. The atmospheric growth rates are strongly influenced by anthropogenic emissions of CH4 and fuel CO2 emissions from a population of spatially condensed point sources that occur over large areas and diverse socio-economic sectors, often in an unpredictable fashion. Estimates of CH4 and CO2 emissions at the scale of individual facilities, and their root causes, remain highly uncertain in many parts of the world; improvements are needed for better scientific understanding, accurate reporting, and actionable mitigation guidance.These high resolution CH4 and CO2 simulations from NASA illustrate that local emissions quickly become a global problem.

Efforts to mitigate (reduce) CH4 and CO2 emissions are complicated by inconsistencies between estimates derived from atmospheric measurements, greenhouse gas inventories, and self-reporting programs. Contributing to these discrepancies are a relatively small number of industrial facilities that emit anomalously high amounts of greenhouse gases, often in an unpredictable and intermittent fashion. Multiple research studies by many teams have provided compelling evidence of “heavy-tail” distributions in CH4 emissions in most economic sectors. In other words, a small fraction of equipment within a region can contribute disproportionately to the region’s total emissions. Our ongoing airborne studies of key US regions suggest that strong methane point sources (concentrated plumes released from infrastructure typically <10 meters across) can contribute up to 20-50% of a region’s total emissions and are highly intermittent in some sectors – particularly for oil and gas production, where half of the high emitting point sources are active less than 25% of the time. Meanwhile, nearly 60% of global CO2 emissions from coal power plants occur in regions that lack facility level emissions monitoring and reporting programs. We are now demonstrating with aircraft and satellite observations the ability to routinely detect, pinpoint, and quantify CO2 emissions from large power plants and petroleum refineries.1 High costs of monitoring systems and incomplete data accessibility and transparency are barriers to diagnosing and mitigating anomalous point sources for geographically dispersed infrastructure. The uneven availability of accurate emissions data also represents a challenge to companies seeking to decarbonize their supply chains while remaining competitive in global markets.

1 Other CO2 sources that manifest as area sources or lower magnitude point sources (e.g., cement and steel plants, flaring at oil and gas production sites, etc) are unlikely to be detected with this technology.

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Remote sensing, in principle, is capable of contributing data that can help fill gaps in current CH4 and CO2 accounting systems and even enable direct action by facility operators and regulators. However, in practice, the ultimate impact depends on the degree of completeness (or what fraction of emissions can be identified and quantified) which is a function of detection limit, spatial coverage and sample frequency. The latter is particularly critical given that many CH4 and CO2 point source emissions are often highly intermittent. This animation shows a time-series of methane emissions from oil and gas production in the Permian basin observed by some of our repeated airborne surveys of the region in Fall 2019. This indicates that the locations and magnitudes of strong emitters can change rapidly from day to day. Some of these emitters are persistent but others are highly intermittent.

Carbon Mapper is designed to detect at least 80% of high emission CH4 and CO2 point sources on the planet through a combination of sensitivity, moderate spatial coverage (high priority regions), and daily to weekly sampling provided by our constellation of multiple satellites. In doing so, Carbon Mapper will contribute to an emerging international system of systems – other satellites and surface-based monitoring systems that will that collectively provide global situational awareness of CH4 and CO2 emissions for many applications.

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