I know that there are differences between increase and increment and decrease and decrement in general. E.g. increase/decrease can be used as verbs whereas increment/decrement cannot, and increment may not necessarily imply an increase in some contexts (Mathematics).
However, I am not aware of any differences in meaning between them when used as a noun in a context similar to this:
The expected increase in global temperatures vs. The expected increment in global temperature
I checked the usage in the English corpus with Google Ngram Viewer and the pair increase/decrease seem to be used more frequently.
Is there a subtle difference in meaning between these two? Would there be a subtle difference, if I used decrease and decrement in the previous comparison?