PHOENIX – Greenhouse gas monitoring was a hot topic at the American Meteorological Society’s annual conference with international agencies discussing a global constellation and companies showing a new generation of sensors.

“We are looking quite hard in Europe, in the Committee on Earth Observation Satellites and the Coordination Group for Meteorological Satellites at a carbon monitoring verification system,” said Ken Holmlund, chief scientist for Europe’s meteorological agency Eumetsat. “Europe is planning three to four greenhouse gas monitoring satellites. We are looking at an international partnership and hoping the United States and Asia will respond to the call.”

Through the Paris climate agreement, 174 countries and the European Union committed in 2015 to undertake efforts to mitigate global warming and to report progress in reducing greenhouse gas emissions every five years beginning in 2023. (President Trump announced plans in 2017 to withdraw the United States from the pact.)

A global greenhouse-gas-monitoring constellation would support national activities to track and report emissions, Holmlund said, calling it “a tool for everybody to work more efficiently.”

China, Europe, Japan and the United States already fly greenhouse gas monitoring satellites but many carry experimental sensors. A global constellation would require satellites and sensors in both low Earth and geostationary orbit, designed for long-term operations, in addition to ground-based sensors to tune space-based instruments, validate satellite data and feed comprehensive atmospheric models, Holmlund said.

Dylan Powell, Lockheed Martin Space weather and remote sensing strategist, said, “It’s incredibly important we make carbon dioxide and methane observations from a variety of platforms — polar, geostationary, ground-based and over water. It is very complex interdependent system that requires a comprehensive observing system.”

Before nations report progress in complying with the Paris agreement in 2023, space and environmental agencies plan to launch: MicroCarb, a mission led by the French space agency CNES; Eumetsat’s Metop Second Generation A; the Methane Remote Sensing Lidar Mission, a joint project of the German space agency DLR and CNES; and NASA’s Geostationary Carbon Cycle Observatory (GeoCarb).

In addition, companies, government and nongovernmental organizations are planning missions. California Governor Jerry Brown announced work in September with Earth observation company Planet on a pollution-monitoring satellite. (The future of that project is unclear since Brown’s term ended Jan. 7.) Space Systems Loral, a Maxar Technologies company, is working with the Environmental Defense Fund to define requirements for a methane-monitoring satellite, called MethaneSat. GHGSat Inc. of Montreal, a subsidiary of Xiphos Systems Corporation, is preparing to launch two Greenhouse Gas Satellites. Bluefield Technologies plans to fly a constellation of 20 CH4 Observation Of Lower troposphere (COOL) microsatellites.

At the American Meteorological Society conference, Powell gave a detailed presentation on GeoCarb, an instrument to detect carbon dioxide, methane, carbon monoxide and solar-induced chlorophyll fluorescence, a measure of plant health, in atmospheric columns. GeoCarb is slated to fly in 2022 as a hosted payload on an SES Government Solutions communications satellite. Focused on the Americas, GeoCarb will be NASA’s first mission tracking methane near Earth’s surface from space, Powell said.

At the conference, Harris Corp. shared information on its Thermal and Near Infrared Sensor for Carbon Observation-Fourier Transform Spectrometer-2, an instrument launched in October on Japan’s Greenhouse Gases Observing Satellite-2 to measure carbon dioxide and methane. “It was the first U.S. commercial greenhouse gas instrument sold overseas,” said Eric Webster, Harris Environmental Solutions vice president and general manager.

Because this type of instrument does not see well through thick clouds, Harris paired the spectrometer with a camera to look ahead at nine fields of view and quickly select the field with the fewest clouds. This technique allows the instrument to collect about 40 percent more useful data than its predecessor, Webster said.

Just prior to the conference, Ball Aerospace and Technologies Corp. delivered Tropospheric Emissions: Monitoring of Pollution (TEMPO), a space-based ultraviolet and visible light air quality spectrometer to the NASA Langley Research Center.

Like GeoCarb, TEMPO, is a hosted payload destined for geostationary orbit. TEMPO “will provide hourly measurements of major air pollutants across North America,” said Dennis Nicks, Ball’s TEMPO program manager. “With hourly scans, TEMPO will be able to see pollution emitted from morning commutes and afternoon commutes as well as the photochemistry and the chemical cycling of pollutants during the day. It will help the scientists better understand emission sources and the impacts of emissions on agriculture and human health.”