Blog about West overwhelmed by frightful climate change (6,7)
I believe the answer is:
global warming
'climate change' is the definition.
(I've seen this before)
'blog about west overwhelmed by frightful' is the wordplay.
'about' is an anagram indicator.
'west' becomes 'w' ('W' can be a synonym of 'west').
'overwhelmed by' means one lot of letters goes inside another (I've seen this in other clues).
'frightful' becomes 'alarming' ('alarming' can be similar in meaning to 'frightful'**).
'w' put inside 'alarming' is 'alwarming'.
'blog' anagrammed gives 'glob'.
'glob'+'alwarming'='GLOBAL WARMING'
(Other definitions for global warming that I've seen before include "Problem facing the planet" , "General temperature rise" , "Peril for the earth" , "Increase in world temperature" , "Heating up of the earth" .)