How about "normal cyclic events". I.E. the earth wobbles, it'* orbit is not perfect and as a result glaciers descend and recede, temperatures make mad swings throughout the ages, and droughts and floods happen with no rhyme or reason. It'* a huge world, and we aren't a big an influencing factor as some would have us believe. Even the disasters like the Exxon Valdez and the Gulf offshore oil platform, nature is able to overcome and life goes on. Reality is something pushed aside to play on emotions and allow others into the masses wallets. Reality says the American bovine food stock produces more methane, CO2, and hydrogen sulfide than all the autos combined. And that doesn't even account for the byproducts from us turning it into tacos and pizza.
....back to our regularly scheduled thread.