(Bloomberg) Oil tumbled to the lowest level in more than five years on speculation a global supply glut that’s driven crude into a bear market will continue through the first half of 2015. West Texas Intermediate fell 2.1 percent to $53.61 a barrel in New York while Brent slipped 2.6 percent, reversing early gains spurred by an escalating conflict in Libya, to close at $57.88 a barrel in London. Fires have been extinguished at three of six tanks at Es Sider, Libya’s largest oil port, which were set ablaze after an attack by militants, said National Oil Corp. spokesman Mohamed Elharari. Crude also fell as the dollar climbed to a two-year high against the euro, reducing the appeal of raw materials as a store of value. Futures plunged 46 percent this year, set for the biggest annual drop since 2008, as the Organization of Petroleum Exporting Countries resisted supply cuts to defend market share in response to the highest U.S. output in three decades.