Loud fans

The last few days/week, my Macbook has been making quite a loud humming noise. I'm quessing its the fans as when the fans spin faster, the noise gets louder, and it sounds like its the fans, so thats my quess.

What could cause this and is it a problem?
My Macbooks only a month or two old. It really shouldn't be doing that.

Probably just the fans, they can get loud sometimes

If your doing something like encoding then your fans will get pretty loud because your macbook will get hotter

I think the fans kick in when your macbook gets about 72-74℃