Bank Shot

Well, one the regulars at my local greasy spoon complained the other day that it was so cold that she had to turn on the heat in her house. And this should be a surprise? Smoke ain't clouds, and really does block the sun. So, in Tinkers to Evers to Chance style, climate change leads to higher temperatures, which leads to deeper evaporation, which leads to more flammable undergrowth, which leads to more intense wildfire, which leads to dense smoke, which leads to lower sun power, which leads to colder temperatures. It's not as if it hasn't happened before.

One of the more well known instances was "The Year Without Summer", back in the early 1800's, and also happened here in the shithole states of New England. That event caused significant harm. Again, particulates blocked the sun, in the 1816 case, from vulcanism. The Canadian wildfire situation isn't likely to have as widespread impact. Gov. DeMented will likely boast that such would never happen if he were President.

Then, of course, there's Snowball Earth. Something to look forward to:

Many possible triggering mechanisms could account for the beginning of a snowball Earth, such as the eruption of a supervolcano

1816 demonstrated that such an event is possible.