Meteors piercing the Van Allen radiation belt cause it to catch fire, resulting in a world-threatening "global warming". The "fire" is making the world's temperature rise alarmingly each day. If it is not extinguished it will soon end all life on Earth. Meanwhile the new, state of the art atomic submarine Seaview is on diving trials in the Arctic Ocean. The Seaview is being put through these trials by the scientific genius who designed and built the futuristic submarine, Admiral Harriman Nelson (Pidgeon). The specific details are being managed by Seaview's Captain Lee Crane (Sterling). There is a team of independent observers on board to appraise the new submarine. Among them, Dr. Susan Hiller (Fontaine). These tests end abruptly when icecap starts sinking around the submarine. The crew brings Seaview to the surface and discover the fire burning in the sky.
Admiral Nelson, along with his friend and fellow scientist Commodore Lucius Emery, do some calculations. They race to an emergency meeting of the world's top scientists at the United Nations, the purpose of which is to figure out what to do about the burning sky. At the meeting Nelson informs the UN that according to their calculations, if the heat increase is not stopped, it will become irreversible and "Earth has a life expectancy of about three weeks." The Admiral has come up with a plan to extinguish the Skyfire. He proposes firing a nuclear missile at the burning Van Allen belt from the Marianas Trench. The idea behind the missile firing is that if fired at the right place and time, 1400 hours on August 29th, the nuclear explosion should overwhelm and extinguish the flames, essentially "amputating" the belt from the Earth. The missile will hit the right place if it is fired from the proper position. The Seaview has the capability to fire the missile. Zucco's burn-out point, however, is beyond that date and time if the current rise rate is maintained.
But the Admiral's plan is rejected by the chief scientist and head delegate, Zucco (Henry Daniel) of France. His reasons are that he knows the composition of gases in the belt and he believes the Skyfire will burn itself out at 173 degrees. Zucco's plan is to let the Skyfire do just that and he feels the Admiral's plan is too risky. At Zucco's urging, Nelson and Emery are shouted down and the plan is rejected by some of the other delegates. Despite the rejection, the Admiral remains convinced his plan is the right one. Nelson and the Commodore return to Seaview and set sail for the Mariana Trench: being the only ones in favor of the plan, only the Seaview can implement it.
It is a race against the clock as Nelson tries to reach the proper firing position in time. There is trouble on board when an unsuccessful attempt on the Admiral's life makes it clear that there is a saboteur among them. But the confusion over who the saboteur is revolves around the scientist rescued by the Seaview in an early scene, Miguel Alvarez (Ansara), and the stress-observing psychologist, Dr. Susan Hiller. Other obstacles present themselves: a minefield, a hostile submarine with orders to sink them, a giant octopus, a near-mutiny and religious fanatic Alvarez, who believes it is God's will that the world end.
Near the end of the film the saboteur is revealed to be Dr. Hiller. Her identity revealed, she falls into the sub's aquarium during a fight with Captain Crane. There she is killed by a shark. The Admiral learns that temperatures are rising faster than expected. He realizes that Zucco's belief that the Skyfire will burn itself out is in error.
At the end of the film, Seaview reaches the Marinas Trench. There, in spite of the threats and objections of Alvarez, Seaview launches a missile into the belt and saves the world.
In June 1961, Pyramid Books published a novelization of the feature film by Theodore Sturgeon. The book was reprinted several times during the 1960s. One of those reprintings has Richard Basehart and David Hedison pictured on the cover. The book is still about the Walter Pidgeon film. Collectors who want a novelization of the TV series should find City Beneath the Sea. That book uses the TV characters but, should not be confused with either the TV episode or the later Irwin Allen film of the same name.
The Sturgeon book is based on an early version of the movie script. The book has the same basic story as the movie. The book also has a few characters that were not shown in the film and some additional technical explanation. Some scenes are different from the film. Some scenes in the book are wholly absent from the film, and likewise some scenes from the film are entirely missing from the book.
The original 1961 cover shows a submarine meeting a fanged sea serpent. Neither the submarine nor the sea serpent appear anywhere in the novel or the film.
In 1961 Dell Comics did a full color adaptation of the Voyage to the Bottom of the Sea movie. The comic was Four Color Comics #1230. The comic book has a few publicity stills of the movie plus a section on the history of submarines. In the comic book the Admiral's first name is Farragut instead of Harriman.
The movie poster shown in the infobox is one of four posters that were made to promote the film. Each has different wording and slightly different drawings. Each poster promotes the movie from a different perspective. The poster shown also promotes Sturgeon's book.
There is also a board game, manufactured by a company called GemColor, that is tied to the movie and not the TV show. The box has a photo of a diver with an eight-foot miniature of the Seaview.
The movie has been released on VHS and DVD.On one DVD the film was co-packaged with the film Fantastic Voyage. When the movie was released on a special edition DVD, the special edition was titled "Global Warming Edition".
There was some interest in a remake or reboot of the film in the late 1990s, but the project fell apart relatively quickly.