This was a fascinating question, I just want you to know.
As for the answer;
I see three possibilities, and none of them are mutually exclusive and you're free to layer as many as you like over one another.
1) Get the power from another character that produces magic in one way or another. Not to hint or anything but as an example, but Shendu would be a nice magic battery once he Echoes a bit.
2) Not to spoil future revelations, but there would be certain in game events which could offer a temporary 'charge' of power. Others in the future that could establish just the sort of the link to the Earth as you suggest, (although with some side effects). To let you know how possible it is, one of the first types of event has already happened and could (read: pretty much will) happen again several times.
3) It's entirely possible to Echo the towers. YEAH YOU READ THAT RIGHT. It'd take a fair few to get it to full strength and would probably be more viable in later Seasons, but it can be done.
As I said, all of those are possibilities individually or all together.
no subject
As for the answer;
I see three possibilities, and none of them are mutually exclusive and you're free to layer as many as you like over one another.
1) Get the power from another character that produces magic in one way or another. Not to hint or anything but as an example, but Shendu would be a nice magic battery once he Echoes a bit.
2) Not to spoil future revelations, but there would be certain in game events which could offer a temporary 'charge' of power. Others in the future that could establish just the sort of the link to the Earth as you suggest, (although with some side effects). To let you know how possible it is, one of the first types of event has already happened and could (read: pretty much will) happen again several times.
3) It's entirely possible to Echo the towers. YEAH YOU READ THAT RIGHT. It'd take a fair few to get it to full strength and would probably be more viable in later Seasons, but it can be done.
As I said, all of those are possibilities individually or all together.