WASHINGTON, July 31 (Reuters) - U.S. oil and gas basins

are emitting around four times more planet-warming methane than

federal regulators have estimated, according to the results of

an aerial survey released on Wednesday by the Environmental

Defense Fund.

The study underscores concern among researchers and

environmentalists that the petroleum industry's contribution to

climate change is much higher than official tallies because of

uncounted releases of the powerful greenhouse gas.

EDF and its partners, which include Alphabet Inc's ( GOOG ) Google

, BAE Systems, and the New Zealand Space

Agency, used a jet aircraft equipped with a spectrometer to

measure methane emissions over 12 oil and gas basins last year.

The project, called MethaneAIR, involved 32 flights between

June and October 2023 and provided data that pointed to an

average emissions rate across those basins of 7.5 million metric

tons per year, EDF said.

EDF said that result was an emissions-rate about four times

what the Environmental Protection Agency estimates. EPA derives

its estimates mainly from industry reports to a database.

The EPA was not immediately available for comment.

MethaneAIR is the precursor to a satellite launched this

spring dubbed MethaneSAT that is meant to provide an even more

accurate estimate of methane emissions, by monitoring

continuously from space as opposed to taking snapshots during

flights. Its first data will be available this fall.

"This tranche of MethaneAIR data is a huge leap forward in

terms of the capability of anything that is out there today and

a small taste of what we will start to see coming from

MethaneSAT," said EDF spokesman Jon Coifman.

Methane, which has a warming potential far higher than

carbon dioxide, can leak into the atmosphere undetected from

drill sites, gas pipelines and other oil and gas equipment.

The U.S. has finalized rules that target large leaks of

methane from oil and gas operations and will introduce a fee for

operators not on track to meet those targets.

The EU also approved methane emissions limits on oil and gas

imports from 2030, pressuring international suppliers, including

those in the U.S., to cut leaks.

MethaneAIR also showed that the observed emissions rate was

eight times higher the target adopted by 50 companies at the

COP28 climate summit in Dubai to limit their methane emissions

intensity to no more than 0.2% by 2030.