May 21, 2022 10:39 pm

Mapping Methane from Fossil Fuel Exploitation

Francis Martin Leon 6 min
Sources of methane emissions. See text for details

one of the main sources of emissions is the extraction, storage and transportation of oil, natural gas and coal, which results in the release of about 97 million metric tons of methane gas each year, according to the United Nations (UN). In a recent research project, scientists mapped where those emissions are coming from, not just by nation, but within them.

Methane is a powerful greenhouse gas that catches some 35 times hotter than carbon dioxide. The United States aims to cut methane emissions 30 percent from 2020 levels by 2030, and other nations are making similar promises.

Temporal and global evolution of methane on Earth. NOAA

Individual countries report their methane emissions by sector to the UN according to the United Nations Framework Convention on Climate Change (UNFCCC). Most countries estimate their methane emissions using records of the amount of each fossil fuel they produced each year, multiplied by an emissions factor provided by the Intergovernmental Panel on Climate Change (IPCC). And most governments only provide one emissions number for each sector (oil, coal, gas) across the country.

Emissions maps

Financed by the Carbon Monitoring System NASA, scientists recently built a new series of maps detailing the geography of methane emissions of fossil fuel production. Using publicly available data reported in 2016, the research team traced emissions from fuel exploitation, or “fugitive emissions”, as the UNFCCC calls them, that arise before the fuels are consumed. The maps delineate where these emissions occur based on the locations of coal mines, oil and gas wells, pipelines, refineries, and fuel storage and transportation infrastructure.

The maps were recently published on NASA’s Goddard Earth Sciences Data and Information Services Center (GES DISC). (Note that 2016 was the most recent year with complete UN emissions data available at the time of this study.)

It is widely known that estimates from self-reported countries are not of the highest qualitysaid Tia Scarpelli, leader of the effort and a postdoctoral researcher at the University of Edinburgh. “Our maps provide researchers with a spatial representation of methane emissions so they can be compared to observations of methane concentrations from satellites.”. Such maps are critical to monitoring changes in greenhouse gas emissions because the data tells scientists where to look and where to expect the most emissions.

The maps indicate that the largest sources of oil-related emissions are in Russia; USA, which leads natural gas emissions; and carbon emissions are highest in China. In the case of oil and gas, emissions are distributed among wells, flares, pipelines, refineries, and storage facilities. For coal, emissions are allocated to where it is mined.

The dark lines stand out on the natural gas emissions map: these indicate the location of the pipes. “Most emissions do not diffuse along pipessaid Scarpelli, who led the research as a graduate student at Harvard University. “They mostly come from compressor stations that are present every hundred miles or so along the pipelines to compress the gas and keep it moving.”.

In Canada, the points on a line show the locations of compressor stations. But for Russia, Scarpelli and his colleagues had no information on the locations of compressor stations or pipelines. They had to digitize a paper map from the Harvard University Library to map the pipelines in Russia and then distribute the methane emissions based on the location of the pipelines.

Comparing the new inventory with methane observations from the Japan Aerospace Exploration Agency’s Greenhouse Gas Observing Satellite (GOSAT) and the European Space Agency’s Tropospheric Monitoring Instrument (TROPOMI) on Sentinel-5, Scarpelli’s colleagues at Harvard found that Canada and the US tended to underestimate methane emissions from fossil fuels. But for coal in China and oil and gas in Russia, the inventory overestimated emissions. This could be due to uncertainties related to the lack of accurate in-situ observations and infrastructure data.

Images of NASA Earth Observatory by Joshua Stevens , using data from the Global Inventory of Methane Emissions from Fuel Operations . Story by Emily Cassidy, NASA Earth Science Data Systems Program.

NASA Earth Observatory

This entry was posted in Reports on 25 Jan 2022 by Francisco Martín León

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