Is *raises the need for* a valid and meaningful phrase?

Blade,

I think you're fine here. "This raises the need for" seems perfectly natural to me. "This gives rise to a need for" is also grammatically correct, although I'll admit, it sounded strange to me as well.

Google's Ngram viewer is far better for checking these types of things than a straight Google search because, among other things, you can limit it to English books. Have a look here for the usage and here for examples in literature.

Hope this helps.

The problem is that "This raises the need for" is correct but it can be understood as "This increases the need for" or "This creates the need for". "This gives rise to a need for...", solves the ambiguity.

Google Ngrams show that raises the need for is at least comparable in idiomaticity with gives/gave/will give/have given rise to a need for (and the need for). We have to take into account that there are more variants hidden in the 'rise to a/the need for' data.

This is as I would have estimated; 'This gives rise to a/the need for...' sound fine to my ears. Looking at the the first 30 results in a Google search for "gives rise to a need for" yields no worrying examples, and mainly examples from businesses / institutions / legislatures in the US and UK.

And 'This raises the need for ...' is, although as you are picking up a slightly odd usage of 'raise' (while 'give rise to' is a familiar idiom), in fairly common use. Again, Google results for a search for the 5-word string are nearly (if not totally) entirely of well-written examples from institutions etc.

As Greybeard points out though, it introduces ambiguity. But, looking at examples on the internet, the 'gives rise to' rather than the 'increases' sense of 'raise' seems by far the more common.