NIST greenhouse gas measurements program
Authors: Whetstone James , Wong Tamae 
Published: June 2024

At COP 21 (Paris), there was general agreement that programs to reduce greenhouse gas emissions and mitigate atmospheric warming will require an understanding of existing emissions as well as programs to monitor, report, and verify emissions from a broad range of sources. Because ~70% of greenhouse gas (GHG) emissions originate from urban environments, where a majority of the world’s population lives, an increased emphasis on monitoring efforts was needed for them. NIST has responded to these measurements and standards challenge as the U.S. Metrology Institute to: a)	improve U.S. capabilities to measure GHG emissions accurately; b)	demonstrate the capabilities of atmospheric urban monitoring networks (top-down or atmospheric measurement approaches) to determine quantitatively GHG fluxes from industrial, residential, transportation, power generation and other activities; c)	complement such measurements with spatially explicit emissions modeling (bottom-up or emissions modeling) approaches based on socio-economic data; andd)	demonstrate that the combination improves confidence in emission estimates while identifying areas of improvement.NIST programs were established to improve measurements of carbon dioxide, carbon monoxide, methane, nitrous oxide, isotopic components of CO2 and oxygen, aerosols, and GHG smokestack emissions. New remote sensing methods were developed applying technologies over large areas and NIST’s gas standards program was expanded to close with NOAA, WMO’s GHG Central Calibration Laboratory to ensure data accuracy and consistency via SI traceability and to strengthen mutual recognition of atmospheric GHG emission measurements. Computational tools were advanced collaboratively with other institutions to model spatially explicit emission sources, biogenic emission and uptake processes, and enable urban GHG source attribution from atmospheric measurements.NIST established its first Urban Test Bed in Indianapolis, Indiana (the INFLUX Project) in 2010 with Purdue University, NOAA, and Penn State University collaborators. Additional testbeds were established Los Angeles (2012) and the Northeast Corridor (2014) to test applicability of methodologies over a range of meteorological conditions and emissions profiles. For INFLUX, results over a 3-year analysis period (2012-2015) demonstrated <3% agreement between top-down and emissions modeling. Testing of the combined approach, bottom-up emissions were offset by +15% with a top-down method correcting this by -14.2%. This performance show sensitivity levels sufficient to track mitigation actions on a yearly basis. (Yearly reduction targets of 1% to 3% are seen across the globe.) More than 200 archival publications have resulted and been cited >10,000 times and fostering successful engagement of an outstanding team of U.S. researchers addressing this global challenge.Workshops were organized collaboratively in China and Europe bringing together the metrology and meteorology communities to address this challenge of common interest. The formation of the Integrated Global Greenhouse Gas Information System (IG3IS) at WMO was catalyzed and are expected initiate international documentary standards on GHG measurements. NIST contributed to the development of a National Strategy to Advance an Integrated U.S. Greenhouse Gas Measurement, Monitoring, and Information System. NIST efforts to quantify GHG emissions are also critical for implementation of the proposed guidance issued by the U.S. Commodity Futures Trading Commission (CFTC) regarding listing of Voluntary Carbon Credit Derivative Contracts in the Voluntary Carbon Market. NIST has contributed substantially to addressing the emissions quantification challenges posed by the Earth’s warming atmosphere and measures aimed at the primary agent driving that warming, greenhouse gases emitted to the atmosphere.