Yep, water takes a lot of heat to make it go in temperature so any change in ocean temps has a large impact on the global average temperature.

Not sure if you know this or not but black Hermione wasn’t a canon claim like Dumbledore. People were criticizing the casting of a play and she was defending the actress, saying “Hermione can be a black woman with my absolute blessing and enthusiasm.”

Imo the worst of the canon claims is that wizards would shit themselves and then apparate it away instead of developing toilets.

Hidden Power doesn’t exist in Gen 9. Although you can use Tera Blast with the appropriate Tera type to replicate that. Note that using your Tera on Heatran will also change your defensive typing for the 3 turns (?) it lasts.