Warning! Spoilers ahead for Green Lantern #2
In the latest issue of DC Comics' Green Lantern, the Guardians of Oa finally reveal why there are so many humans in the Green Lantern Corps. More than any other species in the DC Universe, Earth's representation in the Corps is quite large in comparison. While the real-world reason has been DC's desire to have a collection of varied and relatable human protagonists protecting Earth as Green Lanterns and the greater regions of space, there's finally a solid continuity reason as to why Oa has recruited and given power rings so many humans in the span of one lifetime in the DC Universe.
In Green Lantern #2 from writer Geoffrey Thorne as well as artists Dexter Soy and Marco Santucci, Oa has just been accepted into the new United Planets, a galactic version of Earth's United Nations. While there had been some debate as to whether or not Oa and the Green Lantern Corps would be accepted and allowed to continue their operations as the universe's protectors, the various delegations voted in favor of them joining. However, it appears as though there are some provisos, which the Guardians just spring on the Corps in this new issue after a funeral was held for the death of one the the Guardians seen in the series' first issue.
In cooperation with the United Planets and it's own group of protectors, the Guardians have agreed to reduce it's oversight by quite a bit, vacating 1200 of its 3600 sectors, handing over jurisdiction to the United Planets Brigade. Furthermore, they also split up the Corps' human Lanterns across the far reaches of space. With the notable exception of Lanterns Guy Gardner and John Stewart, the other human Lanterns have been tasked with protecting the most important planets in the galaxy, which the Guardians refer to as Crux Worlds. Furthermore, they explain that these worlds are the reason why there are so many human Lanterns to begin with, as Earth itself is one of these worlds.
According to the Guardians, Earth is the Crux of Heroes, and as such it generated the human Lanterns needed to serve as protectors for itself and its fellow Crux Worlds, providing a greater and more destiny-driven reason for the human Lanterns' numbers. While Green Lantern Hal Jordan will remain as Earth's protector, Lanterns Jessica Cruz and Kyle Rayner are re-tasked with protecting their own Crux Worlds. Furthermore, Simon Baz is tasked with remaining on Oa with the Crux World Mogo being his own protector (seeing as how he's a sentient planet). However, this leaves Guy Gardner and John Stewart himself.
Seeing as how only five of the seven Crux Worlds remain, Guy is not given a world to defend, while Stewart is given a mission leading 1000 Lanterns into the DC Universe's new Dark Sectors (areas the Guardians are unable to look into). Regardless, this new explanation for the greater number of human Lanterns in the Corps is certainly a dynamic one, and it's going to be interesting to see what the ramifications will be now that they're all split up amongst the stars, especially considering the fact that the Power Battery on Oa literally exploded as soon as John Stewart left on his new mission, which can't bode well for future issues of DC's Green Lantern series.