Personal effort by itself can only achieve marginal changes, but political action without personal example will achieve nothing.
Politicians are not stupid. If the environmentalist grass roots do not believe in their cause badly enough to go and change their personal lives first, they will only receive token efforts and empty promisses. And that's because the politicians do (correctly, IMHO) assume than environmentalist only want to wash away their guilt, not achieve actual changes. As in, changes that will negatively affect their personal lives.
Of course, what environmentalist say they want is to have politicians affect everybody's lives... but in practical terms, that means to affect primarily the lives of those that are underrepresented in the political arena. Everybody else is going to push back when real cost come upfront. And since this is the same people that has been thrown under the bus by every other class and group of interest during the last few decades, they cannot be made to pay the cost.
And, more important, for the needed changes to be embraced by enough people to matter, you need a narrative that let them believe they are achieving something of value. That cannot be done with propaganda alone. They need examplars, people who have done what it takes to effect a change in their own lives, who have paid the personal costs, and who are not deprived and miserable because of it, but actually happy and even successful.