The North Pole presently rotates further into the dark hemisphere of the Earth thereby creating an expanding radius to the light hemisphere of the Earth where the Sun remains constantly out of sight. This expanding circumference will reach a maximum on
the December Solstice and encompasses an area which is called the Arctic Circle with the polar coordinate at its centre.

Arctic sea ice follows this expanding circumference even though there is a lag in the appearance and disappearance of sea ice in the same way the warmest part of the day lags noon when a location at lower latitudes is midway to the dark hemisphere of the
Earth as a function of daily rotation.

Planetary climate at its broadest approach is defined by the extent of that expanding and contracting circumference and therefore a property of the relationship between axial orientation relative to the orbital plane. It covers all planets in the solar
system-

https://calgary.rasc.ca/images/planet_inclinations.gif

Jupiter has a tiny equivalent of an Arctic Circle giving the planet an Equatorial climate while Uranus has an extremely large equivalent of an Arctic Circle giving that planet a polar climate.

The Earth has an equatorial climate with a sizable but minor polar input. It takes a number of major modifications based on a resolution of an issue that was not available to Copernicus and Galileo.

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