The speaker is anxious about the state of the world, and the poem is built from that anxiety. Most of it is a string of "what if" questions: the bees might not return, the maple trees and earthworms might leave, the sky might harden into a plastic dome, the wells might go dry. Alongside these big fears sit small, practical details. Garlic mustard is spreading and can't possibly all be pulled. Living in the country means driving everywhere, which the speaker seems to see as part of the problem. Wars appear too, stated flatly: "I think the wars will never end."
The ending is the turning point. The speaker makes compost "out of everything" and says, "I'm trying to write this poem." Both are modest efforts, and the word "trying" admits they may not be enough. The mood is worried and uneasy, but also honest and a little tender. The short lines and plain speech make the fear feel personal, like someone thinking aloud, and the poem ends on stubborn, small-scale action rather than despair.