Via Jonathan Adler, I see that a group of scientists doing "scenario analysis" on the potential outcomes of human contact with extra-terrestrial intelligence is worried that global warming will encourage those aliens to wipe us out:
The authors warn that extraterrestrials may be wary of civilisations that expand very rapidly, as these may be prone to destroy other life as they grow, just as humans have pushed species to extinction on Earth. In the most extreme scenario, aliens might choose to destroy humanity to protect other civilisations.
"A preemptive strike would be particularly likely in the early phases of our expansion because a civilisation may become increasingly difficult to destroy as it continues to expand. Humanity may just now be entering the period in which its rapid civilisational expansion could be detected by an ETI because our expansion is changing the composition of the Earth's atmosphere, via greenhouse gas emissions," the report states.
"Green" aliens might object to the environmental damage humans have caused on Earth and wipe us out to save the planet. "These scenarios give us reason to limit our growth and reduce our impact on global ecosystems. It would be particularly important for us to limit our emissions of greenhouse gases, since atmospheric composition can be observed from other planets," the authors write.
It was ever thus . . . it's really remarkable, in fact, how often the aliens in science fiction just happen to be preoccupied with the exact same political issues that obsessed intellectuals of the era when the fiction was written. And yet it's still somehow breathtaking. They don't even notice that they're not noticing all their embedded assumptions. For example, the scientists do not even consider the possibility that the recent decline in church attendance among the citizens of the world's most powerful nations could be a signal to advanced, god-fearing aliens that we are a decadent and irreligious species who should be wiped out.
We could just as easily speculate about an advanced alien race seeing things quite differently. Perhaps the aliens would come from a planet with a much warmer temperature and see global warming as our invitation for them to colonize the planet. Or maybe they'd see gradual warming as a sign that we are a productive civilization that has been able to conquer and subdue our natural environment and is therefore worth trading and cooperating with. Or maybe this race would follow something like the "Prime Directive" and see our expansion as a reason to just leave us alone.