I feel obliged to point out that the massive hypocrisy, energy waste, and enormous carbon footprint of the Live Earth concerts do not invalidate their claim. History is replete with people advocating for causes while not living up to their ideals. Most young environmentalists are hypocrites; so what? Most everythings are hypocrites. I sometimes find it remarkable that we rise out of selfishness long enough to do any good at all.
Yes the sanctimony is irritating, but it is irrelevant to the truth. The same is true for all the kicking of Al Gore about his personal exploitation of the environment and John Edward's exploitation of the poor. The hypocrisy might be a valid consideration as to whether we elect them but it does not in itself invalidate their causes, any more than randy preachers invalidate Christianity.