Like actual climate change, there are Thrones skeptics
Not everyone agrees with this interpretation, of course, not even George R.R. Martin. One of the commonly cited counters to the Thrones-as-climate-change-metaphor argument is an answer he gave to an audience member, who asked him about the potential allegory, at a 2013 event:
"Like Tolkien I do not write allegory, at least not intentionally. Obviously you live in the world and you’re affected by the world around you, so some things sink in on some level, but, if I really wanted to write about climate change in the 21st century I’d write a novel about climate change in the 21st century."
He went on to explain that he began outlining and writing the books long before events like the Iraq War and other globally defining conflicts had occurred, so any similarities are post hoc. All of that's fair, and perhaps it's best not to talk up the themes within a fantasy novel series about dragons and magically forged swords when they affect folks in the real world. However, that wasn't his final word on the topic. In November 2014, in an interview on Al Jazeera America, Martin described his thinking behind the political undertones of his books' various different plotlines: