This is a given in the Self-rule act, chapter 8. It is stated in very clear terms that the decision about the independence of Greenland (Kalaallit Nunaat) is made by the Greenlandic people. In reverse order, the process is as follows:

7: Greenland is independent after
6: The Danish Parliament has given its consent
5: to the result of a referendum in Greenland
4: based on Inatsisartut's approval of the result of
3: negotiations between Naalakkersuisut and the Danish government
2: which will commence once the people demands these negotiations on the terms for independence
1: following a sound and constructive debate (which is exactly what we ask for on these pages).

The Self-rule act acknowledges that the Greenland people is a proper people as defined in the people rights, and that the Greenlandic identity is different from the Danish. By the same token it has therefore also been stated by the same law that the official language of Greenland is Kalaallitsut / Greenlandic (§20).