Blame Assignment

As I often I point out, it's the major parties that are "stealing the votes" from the Greens. No one voting for third parties is doing so in spite of the fact that they really want to vote for someone else, unlike major party voters. The Green agenda is the only one that truly aims to mitigate the Climate Crisis at its core, which will also have many other positive side effects in order to actually be put into place. The time to have started that work and to treat it seriously was way more than 30 years ago.

A party or faction doesn't have to win to be influential in politics - see the Republicans for an example - but having the ideas vigorously brought up in every debate is important. 

The Climate crisis is basically "whataboutism" turned inside out: literally everything else is "whataboutism". 
I like to point out Brecht's take on the Buddha's Parable of the Burning House. 
https://www.mysteriology.com/blog/the-buddhas-parable-of-the-burning-house-by-bertolt-brecht/

It will change civilized human life patterns, and not for some far off generation either. It will also take down functioning ecosystems, and to some extent, even change geography through shifting shorelines, receding glaciers and melting permafrost. The buck has already been passed to us, and we're left holding the bag (block that metaphor). There is no natural process - which is the only thing that can treat the crisis at scale - in place or planned to be in place that can deal with the enormity of our environmental sin. 

Good luck being, say, pro or anti choice as your house is swept away in a flood or derecho, your hospitals burn to the ground in wildfires, and you and your family and friends become sudden climate refugees in places where municipalities and their governments cannot handle the massive influx.