Here is the full list of all 17 Terra Nil achievements.
Completely restore the planet
Restore the Irradiated Sprawl
Restore the Polluted Fjord
Restore the Volcanic Glacier while still having at least 15 lava tiles
Discover all animal species and fully restore biomes and climate conditions in the polar region
Restore the Archipelago
Restore the tropical region with at least 40% of the map being underwater
Have 3 bears living on 3 different hills at least 10 tiles apart in the River Valley
Restore the Abandoned Quarry
Create rock by causing lava and river to meet
Construct an Animal Observatory at the intersection of 4 different tier 2 biomes
Discover all animal species and fully restore biomes and climate conditions in the continental region
Discover all animal species and fully restore biomes and climate conditions in the tropical region
Restore the River Valley
Appreciate the beauty of nature for at least 60 seconds
Use screenshot mode to take a full map screenshot
Burn down 25 buildings with a single fire