Iraq says it has 25 per cent more proved oil reserves than the last time it looked. The revised estimate is 143bn barrels, the world’s third-largest after Saudi Arabia and Venezuela (excluding Canada’s oil sands). Iraq’s oil minister said there might be further upward revisions over time. Brazil says one of its recent discoveries could be 8bn barrels, twice as big as first estimated. According to BP, global oil reserves were 1,333bn barrels at the end of 2009. That was 23 per cent higher than a decade earlier, despite consumption of 300bn barrels over the period.

Global oil production last year suffered its biggest percentage fall since 1982, but it still does not sound like oil is reaching Hubbert’s Peak, when reserves start to fall and prices rise inexorably. That inflection point will arrive some day, but it remains a moving target, continuously delayed by new data and discoveries. M?King Hubbert, the geologist after whom the theory is named, predicted US oil production would peak in 1970, and it did. But he did not anticipate the growth of global trade or the improvements in oil industry technology and geological knowledge.

The peak oil theory reached its own recent peak in popularity when the oil price hit $147 a barrel. Then it was deployed as an ex-post justification for rising prices. Now the industry has more immediate concerns. These include the rising cost of extraction, the impact of BP’s Gulf of Mexico accident, and resource nationalism. Nomura estimates that seven of the top 10 source countries shut out western oil companies (Canada, Iraq and Kazakhstan are the exceptions).