Recycling paper's sustainable - with a twentyfold increase at the start to make it significant (11)
I believe the answer is:
appreciable
'sustainable with a twentyfold increase at the start to make it significant' is the definition.
I can't judge whether this definition defines the answer.
'recycling paper's' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'paper' is 'appre' which is within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for appreciable that I've seen before include "Large enough to be noticed" , "Enough to be taken into account" .)