In the fragment “Young and thin ice can regrow relatively quickly once the dark and cold winter sets in.” (lines 55-57), sets in…

Available at: <https://www.washingtonpost.com/energyenvironment/2018/12/11/arctic-is-even-worse-shape-thanyou-realize/?noredirect=on&utm_term=.508085a17318>. Retrieved on: July 2, 2019. Adapted. 

In the fragment “Young and thin ice can regrow relatively quickly once the dark and cold winter sets in.” (lines 55-57), sets in can be replaced, without change in meaning, by