The United Nations urged donor nations on Friday to provide $80 million for an emergency operation to remove a million barrels of crude oil from a tanker moored off the coast of war-torn Yemen since 1988 that could explode or leak causing a major environmental disaster in the Red Sea and beyond. David Gressly, the U.N. resident and humanitarian coordinator for Yemen, made the appeal saying the FSO Safer tanker is “a time bomb” because a major oil spill from it “would unleash a massive ecological and humanitarian catastrophe centred on a country already decimated by more than seven years of war…