Humanity, for the most part, is responsible for the damage we have done to this planet... but to be honest, I think the main culprit for the extreme weather changes are because of the poles moving.
The North Pole appears to be moving towards Siberia away from Canada. If this trend continues, in the next 50-100 years, Canada would probably be comparable to US weather with much less snow.
That's why warm places getting cooler, vice versa; as well as bodies of water changing.
https://www.popularmechanics.com/science/environment/a32496561/why-magnetic-north-pole-moving/







