"I've been involved in legal hearings on different land use issues back in Ontario and I know it takes a lot of volunteer hours and a lot of expert hours, so there's a lot of money involved to mount a good legal challenge," she told The Early Edition's Rick Cluff.
Harmer travelled the route of the proposed pipeline through the Nobel Women's Initiative, meeting with women living in the communities along the route.
"It was a really first hand account of the positions of communities," she said.
Harmer is performing at a benefit concert at Vancouver's York Theatre tonight as part of Pull Together — a campaign to raise legal funds launched by the Sierra Club and RAVEN Trust.
But Harmer said that money will only go so far — and said bigger changes are needed for Canadians to lessen their dependence on fossil fuels.
"We got ourselves here and I know we can change our direction … but we really have to stand up and change some things right now," she said.
To hear the full interview with Sarah Harmer, click the audio labelled: Sarah Harmer adds voice to Pull Together.