Pole shift wouldn't affect the climate, but would screw up our compasses. The pole shift is a reversal of the magnetic poles. Where our compasses point north now, they would point south after a pole shift. It has happened many times before in Earth's history and the planet is still here.
Solar intensity(brightness) plays a much bigger role in climate change. Seems the sun goes through a cycle where it gets brighter and then gets dimmer and the earth heats up and cools down right in sync with it. The sun is gewtting dimmer right now so we are cooling off.