Superman: The Amazing Transformations of Jimmy Olsen #1

When Jimmy allows Prof. Potter to demonstrate his evolution accelerator on him, he becomes a human from 1,000,000 A.D. who calls himself the Cosmic Brain. Transformed, Jimmy forces Superman to create a crater in the Antarctic icecap and fill it with heavy materials. Only once Jimmy has reverted to his normal self does Superman discover that as the Cosmic Brain Jimmy had figured that the clustering of the Earth's main land masses around the North Pole would some day lead to the destruction of the planet.