How it all could end
Season 7 may conclude before the more intense weather incidents bear out, and as we've learned over the years, any number of characters, plot armor notwithstanding, could die before the climactic flashpoints in the War of Ice and Fire that we're sure to get in the show's final season. But this quote from the work of Charli Carpenter -- as pointed out by Vox and other outlets -- indicates the race to the finish line could directly comment on the climate change theory:
"The slogan 'Winter is coming' is meant literally as well as metaphorically: planetary forces are moving slowly but inexorably toward climatic catastrophe as the infighting among kings and queens distracts them from the bigger picture. This is a collective action story, with the Night’s Watch issuing increasingly desperate alarms yet receiving indifferent shrugs. ...The argument [of the series] seems clear: if existing governance structures cannot manage emerging global threats, expect them to evolve or fall by the wayside."
A "collective action" story sounds a lot like the alliance between the First Men and the Children of the Forest, and is a lot more hopeful than the reputation of Game of Thrones suggests. Following Carpenter, the endgame of Game of Thrones will depend not upon who sits on the Iron Throne, or who screws whose aunt, or who finally kills Littlefinger (rooting for you, Arya), but on whether or not the various forces of humanity that still have money, military, magic, and magnificent dragons can get past their realpolitik and cooperate long enough to fight the forces of evil that are capable of changing the weather.
Maybe Jon Snow can survive this week's madness beyond the Wall long enough to pull it off and eventually prevent a second Long Night, as has been prophesied in the saga. Or maybe, to borrow a metaphor real-life climate scientists have used, our characters have gone "past the point of no return," and their squabbling, wasted time, and the disruption of a natural order have caused such a dent in humanity's ability to confront an inevitable devastation.
The "point of no return" is apt because it sets up the same moral dilemma all of the saga's main characters will face before the end: Do you continue to address the difficult long-term problem like Jon Snow, who faces the danger, knows the danger, has been outnumbered by the danger several times over, and chooses to fight anyway? Do you battle against climate change even though we're "past the point of no return"? Or do you focus on a chair made of swords and your control over people and nations, while your population and countryside freeze over?
If that devastation is inevitable -- and, again, Game of Thrones is not known for hopefulness -- ice will envelop the land before the end of the next season. The Wall will fall. Daenerys Targaryen will die. Jon Snow will die again, and his Ghost will join him. They will return as cold carcasses, perhaps missing an ear, an eye, an arm, but no less certain of their dark, singular mission of destruction. Perhaps Sansa will live to watch the frozen, desiccated corpses of babes feast on the flesh of those still living in Winterfell, before the wight that was Littlefinger turns her into a frigid specter, too. And perhaps even dragons, the Song of Ice and Fire's symbol of hot-blooded hope, will blink through steely blue eyes before the end.