In the absence of a worldwide warming trend, there is a large scale oscillation, the thermal bipolar see-saw. When the arctic cools, the antarctic warms and vice versa. With a worldwide warming trend, even if both are warming, the oscillation will still cause one to race ahead of the other, then switch places.

See https://www.nature.com/articles/ngeo1026

Other differences besides those mentioned in other answers:

• Due to weird chemistry, increasing CO₂ over Antarctica causes a reverse greenhouse effect - it cools the surface! See https://www.nature.com/articles/s41612-018-0031-y
• There is a lot of vulcanism under Antarctica. We don't know how much melting to attribute to that.

In the absence of a worldwide warming trend, there is a large scale oscillation, the thermal bipolar see-saw. When the Arctic cools, the Antarctic warms and vice versa. With a worldwide warming trend, even if both are warming, the oscillation will still cause one to race ahead of the other, then switch places.

See the article Expression of the bipolar see-saw in Antarctic climate records during the last deglaciation.

Other differences besides those mentioned in other answers:

• Due to weird chemistry, increasing CO₂ over Antarctica causes a reverse greenhouse effect - it cools the surface! See the article Unmasking the negative greenhouse effect over the Antarctic Plateau.
• There is a lot of vulcanism under Antarctica. We don't know how much melting to attribute to that.

In the absence of a worldwide warming trend, there is a large scale oscillation, the thermal bipolar see-saw. When the arctic cools, the antarctic warms and vice versa. With a worldwide warming trend, even if both are warming, the oscillation will still cause one to race ahead of the other, then switch places.

See https://www.nature.com/articles/ngeo1026

Other differences besides those mentioned in other answers:

• Due to weird chemistry, increasing CO2 over Antarctica causes a reverse greenhouse effect - it cools the surface! See https://www.nature.com/articles/s41612-018-0031-y
• There is a lot of vulcanism under Antarctica. We don't know how much melting to attribute to that.

In the absence of a worldwide warming trend, there is a large scale oscillation, the thermal bipolar see-saw. When the arctic cools, the antarctic warms and vice versa. With a worldwide warming trend, even if both are warming, the oscillation will still cause one to race ahead of the other, then switch places.

See https://www.nature.com/articles/ngeo1026

Other differences besides those mentioned in other answers:

• Due to weird chemistry, increasing CO₂ over Antarctica causes a reverse greenhouse effect - it cools the surface! See https://www.nature.com/articles/s41612-018-0031-y
• There is a lot of vulcanism under Antarctica. We don't know how much melting to attribute to that.