A new study suggests many countries are underestimating methane emissions from offshore oil and gas production. 

A recent study from researchers at Princeton University and Colorado State University has found that the current method for estimating methane emissions from offshore oil and gas production in the United Kingdom systematically and severely underestimates emissions. 

The study finds that as much as five times more methane is being emitted from oil and gas production in the UK than what the government has reported. 

The researchers reached this conclusion by critically evaluating the UK’s current method of calculating methane emissions, suggesting alternative, peer-review based methods and generating revised emission estimates.

Since many other countries use similar methodologies to calculate methane emissions from oil and gas production, this severe underestimation is likely not confined to the UK alone.

Due to its climate and indirect health impacts (methane is a precursor for ozone which is an air pollutant that damages human health and crops), methane mitigation has recently become a global policy priority. 

Its relatively short lifetime of about 12 years and high heat trapping ability per molecule makes reducing methane emissions among the most effective ways to slow the rate of climate warming. 

As a result, in 2021 countries signed the Global Methane Pledge, committing to reduce methane emissions by at least 30 per cent of 2020 levels by 2030.

Countries compile national emissions data into inventories, such as the UK’s National Atmospheric Emissions Inventory (NAEI), which are then reported to international monitoring bodies.

The recent study focuses on methane leakage associated with discovery, extraction, and production of oil and natural gas. 

These methane emissions are typically calculated by multiplying the activity level of various processes – namely venting, flaring, processing and combustion activities on production platforms, offshore oil loading, and gas transfer by high-pressure pipelines – by “emission factors,” which are standard estimates of the methane emissions associated with each activity.

The researchers found that the emissions factors used in the UK’s reporting are either outdated, rely on unpublished or publicly unavailable industry research, or use generic values recommended by the IPCC. 

Furthermore, these emission factors are usually “static,” meaning that they are not sensitive to factors such as environmental conditions and management practices which could affect emissions from various processes. 

In addition, leakage can occur when the off-shore rigs are idle - an “activity” that does not currently have an associated emission factor.

Noting these shortcomings, researchers updated and revised estimation techniques for each process, and, wherever possible, used dynamic rather than static emission factor formulations that account for varying environmental conditions. 

They also incorporated direct boat-based measurements of methane concentrations around offshore gas platforms in the North Sea collected in summer 2017. These updates resulted in a total methane emission estimate more than five times larger than reported emissions.

More details are accessible here.