Brownfield Output Decline Accelerates, says IEA

The decline in output from mature global oil and gas fields is accelerating amid greater reliance on shale and deep offshore resources, the International Energy Agency said on Tuesday, meaning companies need to invest more just to keep output flat.

The IEA, which advises industrialised countries, is under fire from U.S. President Donald Trump's administration for a recent shift to focus on clean energy policy. A 2021 IEA report said there should be no investment in new oil, gas and coal projects if the world was serious about meeting climate targets.

Tuesday's report warns that without continued investment in existing fields, the world would lose the equivalent of Brazil and Norway's combined oil production each year, with implications for markets and energy security.

"Only a small portion of upstream oil and gas investment is used to meet increases in demand while nearly 90% of upstream investment annually is dedicated to offsetting losses of supply at existing fields," IEA Executive Director Fatih Birol said in an IEA statement.

"Decline rates are the elephant in the room for any discussion of investment needs in oil and gas, and our new analysis shows that they have accelerated in recent years."

Drawing on data from