Fall of the Nations. Raise of the Ice Breaker
Man did not anticipate just how cold the plant would get. There's was a generation indoctrinated on the notion of an ever heating Earth. When the planet refused to bend to the politics, the narrative changed to include any and all forms of inclement weather, yet the spirit of their message remained rooted on an idea that a depleted ozone was increasing CO2 and raising the temperature of the planet.
They were not prepared for the opposite of what they had been trained to believe.
Would they have survived, even if the flawed politics hadn't been so potent? Civilization still would have fallen. Perhaps not as fast.
The survivors took to the seas, onto ice breakers. These were the same heavily modified vessels that the reclamation crews had piloted in their futile attempts to repopulate New York and Boston. They were floating cities, nuclear powered behemoths that rivaled in size to the largest luxury liners.
Mobility was the new means of obtaining power in a world that was slowing to a frozen halt. The mission was to find the remaining pockets of vegetation and life. These pirate governments became the dominant society. Eventually all major population centers on the land reverted to their most base, primal urges.
The generations that no longer remember life on the land were not so naive to think that the earth would inevitably be scorched by their own hand. Their expulsion to the sea was the most damning proof that the planet imposed change despite the beliefs of man.