Shortage beginning to destroy planet (6)
I believe the answer is:
dearth
'shortage' is the definition.
('dearth' can be a synonym of 'shortage')
'beginning to destroy planet' is the wordplay.
'beginning to' indicates taking the first letters.
'planet' becomes 'earth' (Earth is an example).
The first letter of 'destroy' is 'd'.
'd'+'earth'='DEARTH'
(Other definitions for dearth that I've seen before include "Scarcity, paucity" , "Lack of resources" , "In short supply" , "poverty" , "Shortage, lack" .)