@Doomroar I'm pretty sure his uncle says "we're lost" in the "all hope is lost" sense. Like doomed or done for.
@Nk9bjP4A In the book, Axel mentions that the temperature has been increasing. Axel and his uncle aren't wearing their coats anymore and I'd expect the air and the surface of the sea to have been heated by the constant lightning strikes and the balls of fire exploding all over the place. Dunno if hypothermia still happens if it's >30C out. Keep in mind that the novel that this manga adapts was written in the 1860s and that its aim was to show extraordinary journeys (like going to the Moon!!) so it may gloss over some of the practical/scientific stuff to keep the story exciting. Or it may just be wrong in some places if we've made new discoveries in the past century and a half!