Meaning of "a lazy presage of the many wastelands in store for me and of the wasted landfills straight behind"?

Hello everyone. I am reading a novel, and I came across this expression. Could you please let me know its meaning?

So that it all came down to this, didn’t it—this moment, these tears, this dinner in a greenhouse, this party, this woman, this fire in my gut, this roof garden, and this glass dome a world apart with its visionary expanse of the Hudson in midwinter and that tireless celestial beam, which kept resurfacing each time you thought someone had finally pulled the plug on it and which now traveled the sky like a lazy presage of the many wastelands in store for me and of the wasted landfills straight behind—all of it added up to one thing: that if to some, being human comes naturally, to others, it is learned, like an acquired habit or a forgotten tongue that they speak with an accent, the way people live with prosthetic pieces, because between them and life is a trench that no footbridge, no corvus can connect, because love itself is in question, because otherpeoples are in question, because some of us—and I felt myself one in the greenhouse—are green card–bearing humanoids thrust among earth-lings.

- André Aciman, Eight White Nights, First Night

This is a novel published in the United States of America in 2010. This novel is narrated by the nameless male protagonist who meets Clara at a Christmas party in Manhattan. The protagonist is now eating dinner with Clara and other people in the greenhouse, and thinks back to the light beam that crossed the sky when, earlier in the party, he was looking down from the terrace over the streets and buildings.

Here, I guess that, by "a lazy presage," it might mean that the light beam moved slowly and lazily, and seemed ominous that it portended something.

But I am wondering how "wastelands" and "wasted landfills" here are different. Would "wastelands" mean "barren land", whereas "wasted landfills" mean "land which is ruined because trash is buried therein"...? (But this is just my guess.)

Thank you very much for your help.