Right Wing Freaks Out About Aliens | Mother Jones
Which is why the part about climate change is actually compelling. As the writers note, the fact that our output of greenhouse gases is affecting our atmosphere may be what alerts other life forms to our existence, because the earth's spectral signature (or, our specific combination of reflected and absorbed electromagnetic radiation) has changed. Or maybe they have simply observed from afar that we often treat humans that don't look like us kind of shitty and have been driving other species to extinction, and decide that we can't be reformed. In either case, they "may seek to preemptively destroy our civilization in order to protect other civilizations from us."