Why has affected been impacted?

Listening to the news coverage of Hurricane Irene is giving me a headache:

“Sports Events Impacted by Irene”
“Business Impacted by Irene”
“updates from governors and emergency managers in impacted areas”
“travel impacted by Irene”
“millions could be impacted by Irene”
“How you can help turtles impacted by Irene”

I was taught that wisdom teeth can be impacted and meteorites can impact the Earth, but people are “affected.”

I think the problem comes from people’s confusion over “affected” and “effected.” Just like “who” and “whom,” no one is going to convince native English speakers that there is a difference between impacted and affected. And even the Chicago Manual of Style says that it’s OK to use impacted in this way. When it comes to informal speech or writing, pretty much anything goes, as long as your audience understands you. But formal writing is different. My definition of formal writing includes user guides, journals and newspapers, white papers, really any sort of business writing, and certainly academic writing.

According to most dictionaries, “impact” is a stronger word than “affect,” indicating “strike forcefully” (as in a meteorite) or to “fix firmly by packing or wedging” (as when a molar is unable to breach the gum surface). But they also list the definition “to have a direct effect or impact on” which is how most news sources and marketing writers use it. (Really? “Impact” means to have an “impact”?)

My main complaint with using impact(ed) in place of affect(ed) is that it is over used. While watching the news this morning, a reporter was describing an area affected by Hurricane Irene. She used impact and impacted in almost every sentence. At least change it up a bit and use different words to make it less grating on the ears.

Well, my ears, anyway. I know I’m unusual. When I write or edit for my job, I try to remove most of the instances of impact, simply because it sounds/reads bad if you use the same word over and over (unless you’re writing poetry or songs). Here’s an example of academic writing that overuses the word, from http://sciencepolicy.colorado.edu/socasp/weather1/pielke.html. (I highlighted every instance of “impact” in the article.)

Most people wouldn’t notice that and couldn’t care less. However, when I read writing like the example above, the message is lost on me, because I’m focused on what I would consider to be errors.

You know how sometimes you’re reading something and you stop, then read it again, and maybe again, before you can understand what the writer is trying to say? That’s noise. When you write or edit, your mission is to generate a message that is clear and concise and has no noise that would distract your readers from the message. Impact screams out at me from the page, radio, or TV so loudly that I have forgotten what the story was about.