day and night is the main way you can tell as well as the stars moving across the sky, and we can tell it rotates by looking at the sky and seeing the sun move across the sky during the day.
Global warming will cause see levels to rise since a lot of water is stored in ice sheets which will melt. All of the melt water will end up in the ocean causing sea levels to rise.
I hope this helps. Let me know if anything is unclear.
