Their underground campaign classic — "Booties for Obama" — notwithstanding, the new live album released this week by the Atlanta sister duo R.I.S.E. (formerly known as Rising Appalachia) just might be the green soundtrack of the year.

"Evolutions in Sound: Live" showcases Chloe and Leah Smith’s extraordinarily powerful and natural polyphonic range, drawing on a heavily infused brew of original songs, deep roots, and traditional music. Often underscored by a hip-hop-inflected spoken word intent on a "scale down" green revolution, the R.I.S.E. sisters and their guest backup musicians conjure an air of haunting, even entrancing, rhythms and social justice struggles that defy you to resist at your own risk.

This album’s live version of "Scale Down" — previously recorded on the duo’s second album — is a landmark recording for the times. Backed up by Maurice Turner’s wonderfully understated trumpet, Imhotep’s hand percussion, and Chloe’s unaffected harmony, Leah raps beyond the self-conscious hipness of most Def Poetry Jam cats and makes the case for the listener to get out of your car, "take a long hard look at you," and our environmental impact on the world, and "scale that down, too."

Apt to chat on stage about organic farming, herbs, and feminist chickens, as well as the role of meditation and music, the Smith sisters are part of a new 20-something generation of genre-bending, eco-wise musicians who travel the world in search of songs that have changed the way we live. Leah even offers her own poetic "state of the nation."

Raised in urban Atlanta on mountain tunes by a fiddling mother, both Chloe and Leah can skillfully play banjo and fiddle, but break away from most traditional musicians with their bluesy and jazz-licked versions of Appalachian, African, and traditional classics. Backed up by the funky rhythm of bassist John Branigan, Chloe’s gorgeous voice soars in turning the classic, "Oh Death," from a plea to an act of resistance. On Bill Withers’ classic, "Ain’t No Sunshine," the sisters play a lilting minor banjo pluck off their harmonies.

With a strong emphasis on their voices as instruments, unafraid to allow themselves to wind around each other with enough tension and dissonance. R.I.S.E. delivers a beautiful version of the Congolese traditional song, "JeJeBonge," and the Appalachian ballad, "Raleigh and Spencer."

It’s unfair to label such an evolving act. But with the unabashed political commitment and emerging talent in the tradition of rap godfather Gil Scott-Heron, the musical prowess of Marie Daulne and Zap Mama, and the light carbon footprint of gypsies, R.I.S.E.’s new live album is certainly the kind of music you can believe in.