[acqq]

The reached tipping point they mention is that the current objects will collide often enough to continually produce even more debris. That means that the generation of the new objects happens certainly much faster than the burning in the atmosphere.

http://en.wikipedia.org/wiki/Kessler_syndrome

http://webpages.charter.net/dkessler/files/KesSym.html

"today, the catalogue contains about 13,000 objects, or more than 3 times as many objects. This gives a collision rate that is more than 10 times what it was just over 30 years ago, or 0.13 per year….which is the same as one catastrophic collision between cataloged objects every 8 years….with the time between collisions rapidly becoming shorter as the catalog continues to grow. The larger fragments from either explosions or collisions will further accelerate the rate of collisions."