In brief
Drawing on the production records of around 15,000 fields, the IEA estimates that global oil output would fall by about 8% a year, and gas by about 9%, if investment in existing fields stopped. Shale and tight oil would decline fastest.
Natural decline rates are steeper than in 2010, which the report attributes to greater reliance on unconventional sources, more deep-offshore fields and a larger supply base. Supply would also concentrate in the Middle East and Russia.
In the report's words, "the interplay of investment decisions, economics, and regulation will shape supply resilience and market stability."
