'The 100' season 4 spoilers, cast news: Zach McGowan promoted to series regular; Showrunner teases 'Earth strikes back' in upcoming season

The cast and showrunner of "The 100" were present at the San Diego Comic-Con, and they shared a few details about the upcoming fourth season, hopefully to tide fans' anticipation over until next year when the newest installment finally airs.

Those who follow the show know that based on the events from last season, the Earth would become uninhabitable in six months. Apparently, the continued rise of global radiation would make the possibility of a second apocalypse likely when "The 100" season 4 returns to the small screen.

"The world is going to end... again!" Digital Spy said, quoting what showrunner Jason Rothenberg told the press at San Diego Comic-Con.

"Season four is [when] the Earth strikes back. We'll see the environment beginning to collapse and crazy s**t will start happening. I think it's in our DNA at this point that if we say something's going to happen, it usually happens – there's no 11th hour save. So it's about how the characters are going to survive this, not whether they can stop it."

Even Henry Ian Cusick who plays Kane in the series said fans could expect "a lot of carnage, a lot of guilt and a lot of insecurity" in the wake of a second apocalypse.

Meanwhile, Rothenberg said they could possibly tweak the plot of the series to accommodate the possible return of Lexa (Alycia Debnam-Carey), Clarke's (Eliza Taylor) love interest. It would be recalled that just when their romance was taking off the ground, the show killed Lexa by accident.

Rothenberg said the character could make a comeback, but should that happen, it won't be in the upcoming season.

In other news, Entertainment Weekly said it was confirmed at "The 100's" SDCC panel that Zach McGowan, who joined the series' third season as Roan, the son of the late Ice Queen Nia (Brenda Strong), has been promoted to series regular.

In the series, he became the King of the Ice Nation when his mother died. So the upcoming installment could see more of McGowan in this crucial role.

"The 100" season 4 will return to The CW next year. In the meantime, check out Andy Swift's interview with the cast of the show during the SDCC below.