WARNING: The following article contains spoilers for Superman and the Authority #1, on sale now from DC Comics.
Superman's newest potential future diverges greatly from most others in Superman and the Authority #1, by Grant Morrison, Mikel Janin, Jordie Bellaire, and Steve Wands. In this future, the Kryptonian's powers are beginning to wane instead of growing more powerful with age. And with that comes consequences for the world. The Man of Steel is living up to his name less with every passing moment and he needs a new way to compensate to protect the world. The Justice League has failed in it's mission, at least in Superman's mind, so instead of being reactionary, he's opting to become proactive. And to do that, he needs the Authority.
The idea of the DCU without Superman is a terrifying one. There have been plenty of Elseworlds stories that have explored realities without Clark Kent and they are usually worse off for it. This world still has Superman, but is on the fast track to losing its once invulnerable protector. The Man of Tomorrow knows he has to adapt to the changing situation, and he's accepted what went wrong with his last team.
Superman is avoiding all the problems of the past by reforming the Authority, a team that was originally founded around the idea of aggressively stopping threats before they occur. Superman is seemingly aware of this as he recruits the first member of his team, the ruthless Manchester Black. But his willingness to include someone so dangerous to save the world the "right way" indicates that Superman is done with the moral restrictions of his former teams.
As he described it, teams like the Justice League became lazy and selfish in their approach to protecting the world. They became too focused on their personal conflicts, their villains and crises events. As a result, they lost perspective of what they were truly fighting for: a better world. Every victory over those who would conquer the world or outright destroy it convinced them more and more that they were winning. In the process, they lost sight of the fact that merely protecting the world wasn't enough to build the future they wanted to see. In short, they could have done more with their gifts to improve the world around them.
Superman has now reached the point where he's grown tired of merely reacting to whatever problem comes his way instead of doing something to prevent it from ever happening to begin with. But now it's too late for him to act on this knowledge by himself. His powers are fading, as evidenced by the fact that it takes effort just to levitate a few inches off the ground now.
Saving the world alone is no longer an option for him, but the people he would normally turn to when looking for allies would most likely not agree with his new, more proactive stance. However, the Authority built a name for itself by doing exactly what Superman is proposing. And more importantly, they have the firepower to carry out the mission, perhaps even to compensate for whatever powers are missing from his repertoire.
This also indicates that Superman may be getting desperate. Whatever plan he has to save the world clearly requires more than he can offer and his choice of allies is limited. He just has to hold onto the hope that deep down, people want to leave behind a better world than the one they inherited. And the Authority is precisely the type of team Superman needs to get the job done.