LIBYA'S deadly flash flood in September constituted a climate and environmental catastrophe that requires $1.8 billion in reconstruction and recovery, an international report said. Huge swathes of the city of Derna were destroyed in the flood, after heavy rainfall from Storm Daniel crashed through two aging dams, sweeping entire districts into the Mediterranean. The report by the World Bank, United Nations and European Union said the disaster affected about 1.5 million people or 22% of Libya's population, and cited figures from the U.N. humanitarian agency OCHA of 4,352 confirmed deaths with 8,000 still missing. Libya has been split since 2014 between rival…