Is there a significant difference between Scottish and Irish Gaelic?

I'm from Cape Breton, Nova Scotia... and there are still some people that speak Gaelic in the area... but contrary to what most people seem to think, none of the younger generation does! Anyway, the Gaelic there is mostly Scottish Gaelic and I am just wondering if there is a big difference between the Gaelic from Scotland and the Gaelic from Ireland? Is it so significant that Irish and Scottish Gaels would not be able to understand each other or so insignificant as to be equal to the difference between Canadian English and British English. Thanks for your help!