Hot? yes, but apparently cooler than England right now as long as you're a meter below ground in a ring around the poles (how's a constant 21c/70f sound)
this guy's website is so weird but I love the novelty of the idea and he portrays a plausible scenario for it being ultimately more habitable than Mars
There are stellar phenomena that could burn the atmospheres off of every planet in the solar system at the same time and we wouldn't know until the trees caught on fire. It is really best not to think about how fragile this planet is.
yeah gamma ray bursts and stuff