For governments to do anything, individuals need to do at least one seemingly ineffectual thing: vote. But voting is a poor signal. You vote in most cases for representatives and these representatives stand for many things. To improve the signal you need to show this is why you voted, and that you will do it again. By doing the small, seemingly ineffectual things you can do as an individual you are signaling your preferences to people who can do more.

And more than this, by doing something, anything, you are in effect voting for the behavior you think is acceptable in your society. You yourself are more likely to do another small thing. Your neighbors will be a little less enthusiastic to be seen doing nothing. People, everyone, is looking for an excuse to pamper their present selves at the cost of other people and their future selves, but few people are so thoughtless and selfish that they will do this in all circumstances. By making this choice a little less comfortable for yourself and others, you shift the ratio: how much burden you and others will take on now versus how much you put off on others.

The truth of the matter is that if everyone would just do the little, seemingly ineffectual things we wouldn't need the government to compel us or engineer our incentives. The fix we find ourselves in is the cumulative result of many individuals doing small, seemingly ineffectual things that made things worse.

Fridays for Future and Extinction Rebellion are examples of such things - I think there's scope for much more across various politicals affiliations and leanings.