CAREER: Methane emissions from the US and Canada -- novel insights from an expanding observation network

Methane is the second-most important greenhouse gas (GHG) after carbon dioxide in terms of its climate impact. Compared to carbon dioxide (CO2), methane (CH4) has a much shorter residence time in the atmosphere approximately 9-12-years compared to 300-1000-years for CO2. However, the global warming potential of methane is 28 times larger than that of carbon dioxide over a 100-year period.

In the United States, several federal and state agencies have set goals for reducing methane emissions. However, there are large uncertainties in the current knowledge and accounting of CH4 emissions and how these emissions are changing over time. The overarching goal of this CAREER project is to quantify how methane emissions in the United States, Canada, and Mexico have changed over nearly two decades from 2007-2026.

To advance this goal, the Principal Investigator (PI) proposes to leverage an expanding network of atmospheric methane observations (collected from airplanes, atop TV towers, and satellites) and recent advances in inverse modeling (algorithms and software) that enable the estimations of previously unaccounted sources of CH4 emissions in North America using massive satellite datasets. The successful completion of this project will benefit society through the generation of new data and fundamental knowledge that could be used to (1) better understand and quantify CH4 emissions in North America, and (2) guide the implementation and evaluation of policies and solutions designed to reduce the global emissions of a potent GHG such as methane.

Further benefits to society will be achieved through student education and training including the mentoring of a graduate student at Johns Hopkins University.

Methane (CH4) emissions in North America (United States, Canada, and Mexico) have changed significantly during the past twenty years driven to a large extent by a substantial increase in oil and gas production. This CAREER project will address critical knowledge gaps in the current level of understanding and quantification of CH4 emissions in North America.

The specific objectives of the research are to: (1) quantify how anthropogenic methane emissions in North America have changed over two decades (2007-2026) using a combination of ground-based and satellite observations, (2) evaluate the changing contribution of large and super-emitters of methane in North America using satellite observations from the TROPOspheric Monitoring Instrument (TROPOMI), (3) estimate the distribution and year-to-year variability of CH4 fluxes from wetlands in the United States, Canada, and Mexico, and 4) quantify the relationships between CH4 fluxes from wetlands and key environmental drivers with the goal of developing more accurate and robust process models of methane emissions by wetlands. The successful completion of this research has the potential for transformative impact through the leveraging of an expanded network of atmospheric methane observations and new approaches to inverse modeling that could enable the identification and quantification of previously unaccounted sources of CH4 emissions in North America using massive satellite datasets.

To implement the educational and outreach activities of this CAREER project, the Principal Investigator (PI) proposes to leverage existing programs and resources at Johns Hopkins University (JHU) to develop and deliver two integrated educational activities focused on greenhouse gas (GHG) emissions and climate change (CC). For the first educational activity, the PI will work with the JHU Center for Educational Outreach to create hands-on activities about GHG emissions and CC for Baltimore City middle school students enrolled in the Barclay Summer Academy.

For the second educational activity, the PI proposes to develop an interdisciplinary undergraduate course on GHG emissions and climate policy at JHU that will include discussions with scientists, engineers, and policy experts.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.