I was stretching things a bit, but, the Global Climate Change of 1817-18 and the resulting dicoveries led directly to Franklin going to the Arctic. And the weather was warmer in 1845 than in 1817.
It’s as good a point as any of the Climate Scientist have, but, more realistic.
For those interested in the topic, I recommend reading “The Arctic Grail”, by Pierre Berton. It’s a great history of the search for the Northwest Passage, Franklin, then the quest for the Pole.