If there is extraterrestrial life out there, and it's watching us, it might just as soon blow us to kingdom come as look at us, LiveScience reports—and all because of global warming. If ETs notice our greenhouse gas emissions and conclude we're expanding too rapidly, they may consider us a future threat and attack "in order to protect other civilizations from us," says a report by researchers at Pennsylvania State University.
"This is a highly unlikely scenario," says co-author Jacob Haqq-Misra, but he notes that the technology is there—we are already reading the chemical composition, or "spectral signatures," of other planets. In fact we have read our own reflected back from the moon, and seen its increasingly disturbing mix of oxygen, methane, and ozone. "If there are intelligent civilizations out there, they pretty much have to have figured out how to grow in a sustainable way," says Haqq-Misra. "We're not doing that."