can you use white sugar in carrot cake

[mum2samandalex]

recipe or does it have to be brown?

I've used white in an emergency before and it was ok

imo you can use white sugar in any recipe that calls for brown. It might not look so "rustic", but the taste won't be affected.

Yes

Yes - but disagree that the taste will not be affected. It will taste different and the texture will also be slightly different. However, this is not "good/bad" difference, just personal preference. The brown sugar not only colours and "opens out" the texture a little, it gives it a depth of flavour - caramelly, fudgyness.
Personally, I like the darker less refined brown sugars for most recipes other than things like shortbread or lightweight sponges (lower to golden, cannot bring myself to use white castor anymore)