system
Given the following post, respond as if you're commenting on Reddit:
human
[Mass Effect] How would you defeat or stalemate the reaper threat?

Imagine current day humanity discovers that the reapers exist and are going to start another cycle, cleansing our galaxy of all space faring species, including us. What can we possibly do with the following years to prep?

25 years

50 years

100 years

200 years

500 years

1000 years

Would we attempt to build stupid big rail guns on the moon? Create our own version of the SPARTAN program? Send a life-ship out of the galaxy? Tell me what you all think could be done or if resistance is futile.
gpt
In the games, there's a news article about a species that had just gotten roughly 20th Century Earth equivalent space travel (ie, maybe a trip to the moon or two, probes in their solar system, that's about all), but lucked into first contact. They had just been invited to send an ambassador to the Citadel when the Reapers invaded. 

Their plan for dealing with it was to recall their ambassador, destroy all their satellites and space stations, and hope that the Reapers either didn't notice them, or considered them a pre-space flight civilization. 

This is probably Earth's best bet in this scenario, too. It's not a great plan, but it does have at least a chance of success. (Some of the species that survived the last cycle were already civilized, but didn't get harvested because they were still confined to a single world.)