In the movie Arrival the aliens say that they will need help in 3000 years. What for? Is it implied or mentioned in the movie because I didn't catch that part. Is it mentioned in 'Story of Your Life' that is the short story the movie was based on?
The aliens never said exactly what they needed humanity's help for, only that they WOULD need it, in 3000 years' time. They didn't even specify if the crisis was combative or political, ecological or technological. It could really be anything.
I haven't read the short story that the movie is based on, so I can't speak to that point.