[en] This review of supply and demand trends in the world petroleum market includes comments on the influence of the Brent quotations, political unrest in the Middle East and OPEC's reaction to the carbon tax proposed during the Rio Earth's Summit on global environmental protection. Overall, the analysis suggests increases in surplus, following a 15 month period of stagnant demand, with increases in Asiatic countries balanced by decreases in the Eastern Bloc nations currently periencing difficulties with their transition economies