Game of Thrones is back. And from what we can tell from the show’s latest trailer, it seems like we might finally see the noble houses of Westeros unite to face the growing threat of the White Walkers, the north-of-the-Wall monsters that command a gigantic zombie army.

The White Walkers are some of Thrones’ creepiest monsters — but they also help tell a really interesting metaphor about climate change.

For starters, the White Walkers are a threat to all humanity: Their zombie minions are equally happy to rip apart people of all nations and noble houses. Yet instead of uniting to combat the shared threat to human existence, the houses in the show spend basically all their time on their own petty disagreements and struggle for power. White Walkers are generally ignored; some nobles deny their existence outright.

Swap climate change for White Walkers and "countries" for noble houses, and it starts to sound a lot like the real world.

Specifically, it sounds like the problem of international coordination on climate change. No one country can prevent catastrophic warming on its own: Every country that's a major greenhouse gas emitter is part of the problem.

Yet the biggest emitters, like the United States and China, are also geopolitical competitors: Both are wary of the other's intentions, making it hard for them to see any kind of deal that limits their emissions as win-win. And even if you get over the US-China hurdle, you have to get a deal that's acceptable to most every other country in the world — including developing ones that need cheap energy to fuel economic growth.

The big wars in Game of Thrones — the Baratheon-Targaryen-Stark-Tyrell-Lannister free-for-all — are basically supposed to stand in for these complications. All of these noble houses are focused on their short-term interests, but pursuing them is blocking the real problem: stopping the White Walkers and their zombie army. Likewise, CO2 emissions skyrocketed in the past 100 years — with potentially catastrophic consequences for the human race.

Summer is coming.