Tips for blocking Ireland's large greenhouse emissions are nonsense (5)
I believe the answer is:
bilge
'are nonsense' is the definition.
(I've seen this before)
'tips for blocking ireland's large greenhouse emissions' is the wordplay.
'tips for' says to take the initial letters (letters at the tips of the words).
The initial letters of 'blocking irelands large greenhouse emissions' is 'BILGE'.
(Other definitions for bilge that I've seen before include "Lowest internal portion of a ship's hull" , "Lower part of hull; nonsense" , "Piffle - part of hull" , "Dirty water in bottom of boat - drivel - nonsense" , "Dirty water collecting on a vessel" .)