Giving away my age here, I remember a science fact article published in the old Galaxy SF magazine on this topic. I'm not sure of the exact date but think it was in the early 50s, written by rocket scientist Willy Ley. He raised the alarm then about the extreme dangers posed by "earth orbit-crossing asteroids," as I think he put it.
He urged an organized astronomical search for others. But I think it was the asteroid cluster that smacked into Jupiter a few years ago that truly raised the hackles of the astronomical community -- and galvanized those who believe catastrophism of that kind and more has impacted all life on earth.
That was 1994’s comet Shoemaker-Levy 9, actually comets, as an earlier encounter with Jupiter apparently had busted one comet into multiple comets. :’)
http://en.wikipedia.org/wiki/Galaxy_(magazine)
“Along with an essay by Gold, Galaxy’s premiere issue introduced a book review column by celebrated anthologist Groff Conklin (which ran until 1955) and a Willy Ley science column that continued until his death in 1969.”