This month’s Research Digest features a series of recent peer-reviewed studies focused on exploring common discrepancies between bottom-up inventories and top-down measurements.
Most Oil & Gas Companies Not on Track to Meet Climate Change Goals
A new transition pathway analysis is performed on for the world’s 52 largest Oil & Gas Companies. Using publicly available emission records, emission targets, and reduction measures, the authors find the vast majority of producers are not on track to meet either Paris Agreement or company goals. Out of all the companies analyzed, only half have emission targets, and only two are on track to reach the 2°C global benchmark. Read more here.
Top-Down and Bottom-Up Reconciliation of Methane Emissions in the U.S.
A new bottom-up approach to Oil and Gas inventories in the US bridges the gap with top-down site-level measurements. The authors extrapolate to build upon previous work of component level equipment inventories and verify statistical validity of their methods with bootstrapping and Monte Carlo simulations. Tank emissions and leaks are found to account for historical discrepancies. Read more here.
Satellite Measurements of Urban Methane are 3X Official Bottom-up Inventories
Using daily observations from the TROPOMI Satellite, researchers are able to accurately assess carbon monoxide and methane emissions in eight US cities. Total methane emissions from older East Coast cities are 1.47 Tg/yr, in contrast to the official EPA estimate of 0.52 Tg/yr. The authors suggest current bottom-up estimates could be scaled up with TROPOMI results here.
Considerable Methane Emissions from Boston Natural Gas Distribution Network
Large discrepancies still exist between bottom-up methane inventories and top-down measurements. Results from an 8-year top-down study suggest 2.5% of natural gas entering the Boston area is lost; this is 3X higher than conventional bottom-up estimates. The authors recommend targeted neighborhood level studies with both bottom-up and top-down approaches in parallel. Read more here.
A New Model for Temporal and Spatial Variability in Methane Emissions
Recognizing that typical inventory methods do not adequately account for variability in space and time, researchers have developed new modelling software. The Methane Emission Estimation Tool (MEET) is tested on complex facilities, highlighting the need for improvements in measurement campaigns. The authors recommend capturing time varying behaviour. Learn more here.
Large Discrepancies in Oil & Gas Methane Inventories in China
A review of bottom-up methane inventory methods shows that relative discrepancy among approaches exceeds 130%. Although all the reviewed studies agree on the general trend of increasing emissions in China, emission factors disagree by an order of magnitude across different representative studies. The authors conclude that the unclear estimates are owing to the combined lack of availability, transparency, consistency, and completeness in inventories. Read more here.
Broad Measures Required for Lasting Mitigation of Climate Change
An analysis considers the impact of different policy approaches to reducing emissions, with an emphasis on the importance of large-scale policy implementation. The authors recommend a balanced approach to credit trading systems with an emphasis on large scale strategies, improved emission credit transparency, and policy stability. Read more here.