A few months ago, reader JF from Milford wrote to express her concern about concerning, the adjective -- as in, "The current unemployment situation is very concerning." She was noticing it more and more on TV news reports, she said, and "I really hate it ... 'concerning' sounds like a made-up word."
I replied that though this concerning did seem to be enjoying a vogue, it wasn't a new use: The earliest quote from the OED -- "I cannot bear anything that is the least concerning to you" -- is from Samuel Richardson's "Pamela," 1741. And I vaguely promised to look into the rise of concerning.
But now I don't have to: Mark Liberman at Language Log, having received a similar query from a reader, has done it for me. He finds that the usage is gradually increasing, but thinks we should remain calm:
Why not just give up, get over it, and look on the bright side? Concerning has plenty of standard precedents ("This is troubling/annoying/terrifying/grating") where a prepositional-phrase version would be odd (?"This is of trouble/annoyance/terror/gratingness"). In fact, of concern is a bit of an outlier, so you could see the change to concerning as a move in the direction of linguistic consistency.
Or maybe you'd rather look on the gloomy side? After all, "some people enjoy watching the decay (as they see it) of everyone else's language," says Liberman. "If you're one of them, then never mind, and many happy returns of the peeve."