Depends what you count as a 'disaster', but how about (keeping it probably pretty much within your audial limits):
by [i[Alchemist (Aus)[/i]: "First Contact" (Actions of the whites against Australian aboriginies), "Great Southern Wasteland" (Strip Mining)
By Sabbat: "For Those Who Died" (Witch burnings)
By Skyclad: "A Good Day to Bury Bad News" (9/11), "Bombjour" (French Nuclear Tests), "Gammadion Seed" (Rise of Fascism), "Jeopardy" (Gulf War Syndrome), "Our Dying Island" (Global Warming), "Schadenfreude" (The Holocaust)
by System of a Down: "X" (The Armenian Genocide)
umm, and probably some more. I'll have a think.