It would be ironic that on or around the mayan date Earth has a magnetic pole shift and thus the weather patterns change, or a series of massive earthquakes that changes the axis or tilt.
Places like Alaska will suddenly see tropical weather. Maybe even tropical hurricanes.
Australia changes dramatically and the interior gets wave after wave of rainfall transforming it into a vast lush fertile land.
The shift is not a flip as one would do with a pancake.
The dipolar field loses its strength and small polarity fields develop all over the earth. These small polarity fields slowly reorganize to a strong dipolar field with a reverse polarity. The sun does this every cycle and it is what creates all the sunspots and CME’s during solar max.