The poem begins with a plain fact: land covers one third of the earth's surface. It sounds like a line from a textbook, and the flat, measured tone is part of the effect. Then the poem shrinks to a fragment, "What goes and stays," which reads less like a statement than a thought turning over. Things leave, things remain, and the poem doesn't say which is which.
The last line, "How does it look now," is a question with no answer attached. It could be asked of the landscape, or of a place the speaker is trying to picture, or of the world after change. The "now" suggests time has passed and something may be different.
The speaker's feelings are never named. What comes through is curiosity, maybe a quiet unease. The mood is spare and open, with a lot of white space around the words. The poem moves from a big, fixed fact to an uncertain question, and that gap is where the feeling lives.