My thought is to look at the other uses of "to address" and "to tackle" and the difference is clear.

In my opinion they are both the same. They both mean you are confronting the problem. The only difference is that "to tackle" implies that the problem is difficult. "to address" seems like the problem will be simple. However, both can be used for difficult or easy problems.

I think "to address" a problem means to explain it But "to tackle" it means to solve it ... dunno if its right or :/