Rises (9)
(Other definitions for escalates that I've seen before include "Increases in intensity" , "Steps up" .)
'rises' is the definition.
('ascend' can be a synonym of 'rise')
This is the entire clue.
(Other definitions for ascends that I've seen before include "Rises" , "Moves upwards" , "Travels upwards" , "Climbs, mounts" .)