he members of the Organization of Petroleum Exporting Countries (OPEC), however, have their own estimations which differs to those made by the EIA. They do believe that there are still huge oil resources in their territories that have not been tapped and exploited. However, with elapse of time and advances of technology, certainly the exploitation of untapped resources will be possible and thus prolonging the lifespan of fossil oil.
According to reports, however, Oxford University scientists, in response to international energy organizations (including producers and consumers), suggested that oil reserve estimates are overstated but have been accepted by public agencies that compile statistics on oil and energy. The researchers have warned that organizations like the International Energy Agency (IEA) and the Energy Information Administration (EIA) are aware that OPEC's estimates are misleading, and could be failing to prepare governments for the oil shortages and price spikes that would accompany “peak oil.” The Oxford researchers said that estimates of global oil reserves are “exaggerated by one-third,” and that conventional oil reserves amount to only 850-900 billion barrels -- not the 1.2-1.4 trillion barrels that are currently estimated. The researchers wrote that the errors in statistics of oil reserves are “broadly acknowledged but not taken into account due to political sensitivities,” saying the IEA couldn't afford to give unpleasant information to Western governments that pay its bills: “The IEA…has to keep its clients happy."
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