GPS locked automatic navigation systems mean that aircraft are more likely to fly into the wake turbulence of preceding aircraft on the same track unless positive action is taken to offset each flight track slightly.
More, and heavier aircraft flying around means more opportunity to fly through aircraft created turbulence, not some effect of global warming.
And RVMS puts aircraft closer together, increasing chance of wake turbulence events.
But isn't this about clear-air turbulence, which is quite different to wake turbulence?