Should we set off a second modifying phrase before a noun?

I know the question itself is awkward! I was going to write something like the sentences below, but I was not sure about the punctuation.

1.Evidence on something is scant in global and almost non-existent in national scale.

2.Evidence on something is scant in global, and almost non-existent in national, scale.

Unless, on something' is there to indicate that you would be including details there, it doesn't add anything and could be omitted, and the order seems to be the wrong way round. I should give the information about the lack of evidence from the smaller area to the larger, for comparison, e.g. 'Evidence is almost non-existent in national scale, and scant (even)in a global scale'.