I think the reality is that even parties who take the issue seriously know the solutions are difficult. Making difficult decisions is a great way to get voted out in the next term.

An example from the US:

During discussions for the recent bipartisan infrastructure deals, Republicans wanted to raise the gas tax to help pay for the bill. Progressives felt it would affect the middle class too much so they pushed it out.

Gas tax isn't exactly a carbon tax. But it is close. So here's a case where the party on the Right wanted a "CO2 tax" but the party on the Left scuttled it. (https://www.nytimes.com/2021/06/24/us/politics/what-is-in-th...)

I think France saw something similar with the "Yellow Vest" movement. I'm definitely not knowledgeable about French politics, but I think a lot of that protest was around an increase in gas tax.

In the US, any party that takes the issue seriously does not get elected in an meaningful capacity. Maybe a city representative, even state representative here and there, but that's about it.

And until that changes there will be very little in the way of action on climate change as the problem is just kicked down the road.

However all that delay just makes the problem harder to fix.

So the choice really is simple.

Find a way to make your government representatives take the issue seriously, or accept the 'catastrophic train wreck' that is just some decades away.

This helps, but there's a time lag, and the person you voted for does not know why you voted for them over the other party. Letting your congressperson know that you care about it by calling them or writing them directly is much, much more effective at getting policies you care about implemented. You should vote (in every election!) because they know who votes and who doesn't, and want to make voters happy -- but you also need to know that this is an issue of interest to you.

Right now, here's a very straightforward way to do that for climate change: https://citizensclimatelobby.org/senate/