people could stop flying for leisure - they could stop using their car for every trip that could also be made by bike - they could vote for politicians that are actually campaigning for changing stuff instead of promising people to keep their lifes as it is - they could stop eating meat every day
there's a lot of stuff a single person can choose to not do that would result in huge change if enough people did it since that would actually allow even moderate politicians to change things that actually matter.
if a politician right now is even thinking about banning beef or tripling the price of gas and making flights even more expensive than that they can pretty much start looking for another job since that would be a huge change for a huge part of the population - if enough people started deliveratly foregoing beef or using the most convenient option possible then we might have a chance.
the problem is that people are fucking lazy and a lot of them are egoistic, too - so everyone just claims that others have to change first...
and then there are those "bUt ChInA1!1!"-guys that totally ignore that china is building more renewables each month than any other country does per year and that they still pollute less per person than western countries and also less in total over the last 150 years than western countries, too.
it's people in the US or Europe that have to lead the charge since they are the ones that profited MASSIVELY from the pollution 100 years ago that led us into this mess...