But the gay marriage was a no brainer because it cost nothing to anyone. Making the climate better requires sacrifice. Still think we should try to be positive.

Except that,

1. We have already exceeded the “worst case scenario” path. We are quite literally in uncharted territory, as none of our climate models have been built for this scenario and we have no “prior art” to give any indications of what kind of climate changes might happen next.
2. On this path, +3℃ will be reached within the next decade and a bit - likely between 2035 and 2038.
3. At +3℃, lethally high wet bulb temperatures and chaotic weather will take out about 4 billion humans within a few short years. Chaotic weather itself will make industrialized agriculture impossible world-wide, as over 90% of all agriculture is shacked to rainfall. And too much is equally as devastating as not enough.
4. The collapse of the AMOC - with a “most likely due by” in the 2050s - will supercharge this climate chaos, causing weather patterns worldwide to whiplash for up to a decade as the planetary climate tries to find a “new normal”. At this point, pretty much any agriculture aside from hydroponics - and less than 3% of crops can be successfully worked hydroponically - will simply be unviable.

We are fucked. Right now, the best we can do is limit the wider environmental damage. Entire ecosystems will collapse, as changes are happening too fast for them to migrate towards the poles. The fastest prior example of climate change that we discovered happened almost 100,000× slower, so entire forests had the opportunity to migrate instead of perishing.

I am all for massive action. Not for humanity - I see zero chance of us surviving as any kind of a going concern into the 22nd century - but for the planetary ecosystem. We must give it the best possible chance for recovery, so that whatever comes after us has the best opportunity to flourish.