Here is the full list of all 17 Land Above Sea Below achievements.
Reach 15 days in a single game
Reach 32 days in a single game
Reach 42 days in a single game
Don't let a single tile to sink for 3 seasons
Don't let a single tile to sink for 5 seasons
Higher and higher II Don't let a single tile to sink for 10 seasons
Expand to 5 islands in a single game
Expand to 12 islands in a single game
Expand to 17 islands in a single game
Play for 50 consecutive seasons in a single game
Play for 100 consecutive seasons in a single game
Play for 150 consecutive seasons in a single game
Plant all 3 Tree of Fall types in a single game
Unlock all special buildings
Complete 10 mini-objectives during one game
Complete 32 mini-objectives during one game
Complete 65 mini-objectives during one game