“Avatar: Fire and Ash” opened with $345 million in worldwide sales, according to studio estimates Sunday, notching the second-best global debut of the year and potentially putting James Cameron on course to set yet more blockbuster records. Sixteen years into the “Avatar” saga, Pandora is still abundant in box-office riches. “Fire and Ash,” the third film in Cameron’s science-fiction franchise, launched with $88 million domestically and $257 million internationally. The only film to open bigger in 2025 was “Zootopia 2.” But there was a tad less fanfare to this “Avatar” film. Sales were notably less than 2022's “Avatar: The Way of Water.”