It's very unlikely, but even the fact that they mention it as a possibility feels just crazy to me.
You don't have to worry if you live in Canada though, I think this is just politicians trolling.
I just find the rhetoric to be a bit obscene (82% of Canadians are against it according to a recent poll!), but this is a question of perspective. Also, some impact (like the additional taxes / tariffs during imports) are real, not just a joke.
So, with regard to Greenland, he specifically refused to rule out military action [0]. Which in diplomatic protocols comes very darn close to threatening a military attacks.
As far as Canada goes, Trump's national security advisors is on the record [4] saying he doesn't think there's any plans about this. Which is also an extremely uncertain way of talking about military action about your closest neighbor. Trump has repeatedly talked about making Canada the 51st state [1], and called Trudeau a "Governor" [2]. Here's a New York time article summing up the types of threats/attacks Trump made wrt. Canada[3].
> he specifically refused to rule out military action
Donald Trump has specifically ruled out a lot of things that he then promptly did. He's also followed through enough that his threats have to be taken seriously. As a result, you get a hodgepodge of half-assed threats, each of which can be plausibly denied until followed through on, at which point you're asked how you didn't see him doing the thing he said he would do.
While it's not exactly a military declaration, Trump said during the joint session to Congress, "One way or the other, we’re going to get it" in reference to Greenland.
Do you have a link?