Ok, now! Be seated and have smelling salts at the ready! You've been warned! The answer is (drum roll and trumpet blast, please)..
INVASIONS BY ALIENS FROM OUTER SPACE!!
(Imagine now the Twilight Zone theme playing)
Read the dire words of warning here! I quote "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."
Who dreams up this nonsense? So "little green men" are coming to earth to tell us to be "little green men" or they'll zap us with their ray-guns? Since at least some of these quacks are NASA scientists (using the word "scientist" lightly), we can only surmise that at least some of this crap is funded by our tax dollars - and at a time when our economy is going down the drain.
Actually "little green men" have invaded this planet already. They occupy high places in academia, mainstream media, the USCCB, the White House, etc. They're called "progressives". We aim to retire some of these in 2012.