James Cameron recently spoke on the Avatar sequel. One the idea of a sequel he said, “We created a broad canvas for the environment of (the first Avatar). That’s not just on Pandora, but throughout the Alpha Centauri AB system. And we expand out across that system and incorporate more into the story – not necessarily in the second film, but more toward a third film.”
He also indicated that the sequel might have anew environment saying, “Part of my focus in the second film is in creating a different environment – a different setting within Pandora. And I’m going to be focusing on the ocean on Pandora, which will be equally rich and diverse and crazy and imaginative, but it just won’t be a rain forest. I’m not saying we won’t see what we’ve already seen; we’ll see more of that as well.”
Cameron did note that he has not signed a deal with Fox to make the sequel yet, but did say that Sam Worthington and Zoe Saldana are already signed to reprise their roles in the sequel.