When leaders of the Organization of Petroleum Exporting Countries meet in Vienna on June 5, they should heed a stern signal from the oil market.
They'll hardly lack reasons to worry, of course, large among which is unusually intense strife among key members.
But they also face ramifications of shrinkage over the past decade in expected need for their oil.
In its International Energy Outlook of 2004, the US Energy Information Administration projected total liquids supply from OPEC of 47.8 million b/d in 2020 and 56 million b/d in 2025 in its reference case.
By the 2014 version of the annual study, published last September, the corresponding forecasts had fallen to 38.7 million b/d and 40.7 million b/d.
OPEC leaders recently have asserted determination not to lose market share to higher-cost competitors able to increase output. Given recent surges from deep water and unconventional resources, concern is warranted.
But EIA's projections for non-OPEC supply in 2020 and 2025 fell by 3-3.5 million b/d between the 2004 and 2014 reports.
Greater pressure comes from diminished expectations about market size.
In 2004, EIA projected global liquids consumption of 110.3 million b/d in 2020 and 120.9 million b/d in 2025.
In 2014, the numbers were 97.6 million b/d in 2020 and 101.8 million b/d in 2025.
Those declines are 11.5% for 2020 and 15.8% for 2025.
To be sure, the oil market is expected to keep growing. But the expected rate of expansion isn't nearly what it was in 2004.
EIA's 2014 outlook carries the liquids-consumption forecast out to 2040. The value that year: 119.4 million b/d. That's 1.5 million b/d less than what its 2004 outlook projected for 2025.
Over the past decade, generally (though not continuously) rising prices, steadily improving consumption efficiency, and fuel-switching can be said to have delayed calendar markers for oil-consumption growth by 15 years.
As economists say, the demand curve is flattening. For OPEC leaders meeting in Vienna, that might be an interesting agenda item.