where does all this debris come from?
Doesn't say, but there's a lot of junk up in orbit, paint chips from things put up there, bolts, micrometeorites, things like that. Some is man made and some probably is not.
"Space debris" usually refers to man-made stuff, anything from defunct satellites to flecks of paint. There are natural things like micrometeorites around as well. The big problem is the more pieces of debris you have, the more collisions are likely to occur, and those collisions produce yet more debris.
I would think the majority is human garbage from the silly space program. While our Oceans are dying we piss away our futures through funding cronies of past administrations----------- One good possibility is that the garbage may shade us from the sun and cool the planet-----sort of a garbage sunscreen?
lol... now that's a bit of wishful thinking. =P
Here's an idea: send up a magnet that will orbit around the earth and collect all of the debris! Pro: you collect a lot of harmful debris. Con: you end up with this huge blog of garbage, flying around the earth at thousands of miles per hour, with consequences more catastrophic than any one of the pieces of debris :/