Catastrophic heating problem AGM will be in Bangor, unusually (6,7)
I believe the answer is:
global warming
'problem agm will be in bangor unusually' is the definition.
I can't tell whether this defines the answer.
'catastrophic heating' is the wordplay.
'catastrophic' becomes 'global' (I can't justify this - if you can you should believe this answer much more).
'heating' becomes 'warming' (synonyms).
'global'+'warming'='GLOBAL WARMING'
Can you help me to learn more?
(Other definitions for global warming that I've seen before include "Problem facing the planet" , "Heating up of the earth" , "Increase in world temperature" , "change in the atmosphere" , "Climate change" .)