There are several cycles that influence weather.
Sunspot cycles, several of them, not just the most obvious 11/22 year one.
The tilt angle of the Earth's axis is not a fixed value. It oscillates yearly a bit plus it has a several thouand year cycle from max to minimum tilt. Currently the angle is decreasing, which tends to produce overall more temperate weather, and the angle will continue to decrease for the next few thousand years. The yearly wobble moves the Arctic and Antarctic circles back and forth approximately 200 meters, but the current trend is polewards in a two steps forward- one step back motion. I've looked but haven't found anything but ballpark numbers for the absolute maximum range the circles move over. Even if I did, I don't know the math to calculate the area of the stripes the circles range over. At any rate, it's a fairly large area, which would be quite a difference in how much of Earth's surface has 24 hours or more constant darkness or constant sunlight per year.
How this would affect climate, even though it would seem that the summers and winters at the poles would cancel out, is due to the way heat works. During winter all that keeps the dark pole from getting super cold is the convection of the atmosphere and water currents. Antarctica will always be colder because it has no water currents to carry heat close to the pole, VS the north where there's water all the way to the pole. The summer pole gains heat due to convection and from direct insolation while the winter pole is radiating heat faster than convection can bring heat in.
Still another effect of orbital mechanics is the eccentricity of Earth's orbit and the precession of it's axis. Currently the northern hemisphere has winter while the Earth is farthest from the Sun. That's why the southern hemisphere climate is much milder, its winter comes at closest approach to the sun and summer at furthest from the sun. The bulk of the Pacific and Atlantic oceans being in the south also has an effect on mitigating temperature swings. In several thousand years, precession will reverse the summer/winter situation, though with the arrangement of land and water, the climate is most likely to shift to a more even situation instead of swapping the current extremes. Hop in a cryogenic freezer and set the alarm to wake up in time to see Antarctica thaw quite a bit.
With all these effects in play (don't forget random factors like volcanic activity, or even asteroid/comet strikes), which nothing can be done to change, it's the height of hubris to think that we- the Human Race, can cause massive climate changes. If you dig back through the predictions of the 'sky is falling' human-caused climate catastrophe people, you'll find that they've drastically scaled them down over time, after the same people held the exact opposite position 'global cooling' for quite a while in the 60's and 70's.
And finally, to illustrate the extreme bogosity of the position taken by Al Gore and others,
"We have to get rid of the Medieval Warm Period." Two other 'inconvenient' events commonly ignored are the 'Maunder Minimum' where records show a period of very minimal sunspot activity and the 'Little Ice Age' which happened around that time- and extended by a massive volcanic eruption that caused the 'year without a summer'. Right now the climate in many places, especially higher northeren latitudes, is not as warm as it was during the Medieval Warm Period. That's when the Vikings tried to colonize Greenland (when it was a botanically lush land) and in England there were commonly cultivated crops that it's still too cool to grow now.
So bring on 'global warming' and get back to the temperatures of that warmer time from ages past. (Nevermind that wayyyyyyyyyyyyyyy back in the ages of the dinosaurs and other fossil eras it was a heck of a lot warmer.)
