This has been peer-reviewed, so it must be true. Apparently, aliens may wage war on humanity because of our greenhouse emissions.
“It may not rank as the most compelling reason to curb greenhouse gases, but reducing our emissions might just save humanity from a pre-emptive alien attack, scientists claim.
Watching from afar, extraterrestrial beings might view changes in Earth’s atmosphere as symptomatic of a civilisation growing out of control – and take drastic action to keep us from becoming a more serious threat, the researchers explain.
This highly speculative scenario is one of several described by scientists at Nasa and Pennsylvania State University that, while considered unlikely, they say could play out were humans and alien life to make contact at some point in the future.”
Speculative is right. Science-fiction writers do this too. They think of potential, unlikely scenarios that humanity may encounter. While history teaches us lessons of the past, science-fiction allows us to learn potential lessons of the future. It seems that is what NASA has employed here, science fiction writers. You just know some Hollywood bigshot is going to want to make a movie out of this, probably the same people who made The Day After Tomorrow.
So, if aliens were using our atmospheric carbon dioxide concentration as an indicator of our development, how could they distinguish the rise from natural factors. Past concentrations have exceeded todays by a factor of ten, so they would have to use the rate of carbon dioxide increase. But, recently doubts have been cast over our influence of atmospheric CO2, so it may not be the best indicator to determine if we are a threat.
If we were a threat to these hypothetical aliens, carbon dioxide levels would be irrelevant, because we would have to have moved pass fossil fuels (and renewables) if we have any hope of achieving interstellar travel (if even possible).