Now, at 70, he is retiring from singing, on a long world tour that will take him to Carnegie Hall on Thursday. He reflected on his career in an interview backstage at the hall. Here are edited excerpts from the conversation.

How did you decide when to call it a day?

Sooner or later you have to face the reality, no? To stop your professional life. The projects I have now go through 2018 and maybe part of 2019 — two years from now. Every time that I go on stage now, I realize much more how I enjoy it, and I realize that the end is very close — so I enjoy it more and more. But I don’t think more than two years.

Is it melancholy to think of this being your last Carnegie performance?

I was thinking today, the first time I ever sang here was in Verdi’s “I Lombardi,” with Eve Queler, and that was December ’72. It sounds scary, but it’s true!