Topics of this game:
- ground that's been frozen for 2 or more years
- is topsoil that freezes and thaws seasonally
- organic matter insulator, stores huge amounts of carbon
- is from the previous ice age
- can be as deep as 1500 metres
- trap heat and raise temperatures globally
- the result of permafrost melting
- the result of greenhouse gas being emitted into the atmosphere
- clues that indicate permafrost deterioration
