Early in the book, protagonist Wang Miao is introduced to Battle Command Centre and given to understand that there is some kind of war or struggle going on, although he's unclear who or what they are fighting. However, according to ex-cop Shi Qiang:
Those in charge are terrified! I know General Chang very well. He's the sort who's afraid of nothing, not even the sky falling, but I can tell that he's worried about something much worse right now. They're all scared out of their wits, and they have no confidence that we'll win.
At this point all that is apparent to the reader (and Shi Qiang) is that there is some sort of conspiracy aiming to disrupt and discredit scientific research, which could have an entirely mundane explanation. Globally, the response seems disproportionate to this, to the point that normal geopolitics has been completely sidelined:
NATO officers are now stationed in the war room of the PLA General Staff Department, and a bunch of PLA officers are working out of the Pentagon.
Clearly, some kind of existential threat to the whole world is anticipated. But did they know that it involved extraterrestrials, or did they think it was merely a human political conspiracy?