The Kessler syndrome is a situation where a major satellite collision causes an increase in space junk, causing a cascading effect destroying many if not most other satellites.
As of 2018, we are losing about one satellite per year due to collisions with space junk, yet these collisions are far too small to cause a runaway effect. Furthermore, action has been taken by the Federal Communications Commission to reduce the chance of this happening and regulations in the US require all satellites launched after March 18, 2002 to be disposed of by controlled atmospheric reentry or a boost into a graveyard orbit after shutdown.
Will Kessler syndrome occur before 2050?
This question will resolve as Yes if between 2018 to 2049 (inclusive), there is at least one calendar year when 10% or more of Earth's operational satellites become inoperable due to collisions with space debris.