It is true that an individual can live as carbon-neutral and eco-friendly as possible without making nary a dent on global warming. However it is also true that all of these individuals have the power to elect people who can to do something. One very simple example I can think of that happened in recent history was Trump pulling the US out of the 2015 Paris agreement on climate change mitigation. If the public at large were educated on the subject, there would be widespread outrage and a lot of pressure NOT to do this - but his base leaned heavily climate-change-sceptic so it was A-OK (bonus: it really triggered the libs which would go down well even with Trump fans who are undecided on climate change). Now, would that agreement alone fix everything and arrest climate change? Probably not, but getting the world to agree on something was one step in the right direction.