One in the morning put out of joint regarding the environment (7)
I believe the answer is:
ambient
'regarding the environment' is the definition.
'one in the morning put out of joint' is the wordplay.
'one' becomes 'i' (roman numeral).
'in the' indicates putting letters inside.
'morning' becomes 'am'.
'put out of joint' becomes 'bent'.
'am'+'bent'='ambent'
'i' put inside 'ambent' is 'AMBIENT'.
(Other definitions for ambient that I've seen before include "air" , "Surrounding or encompassing, say temperature" , "Surrounding - mean bit (anag)" , "Circulating" , "to do with circulation" .)