Of course you're right, and it is quite apparent to me that we will not sort it out; there isn't even a "we" that's really in charge of the global atmospheric CO2 level - it seems like an emergent phenomenon of our civilization. I guess you get used to it after awhile, and it probably helps that I never wanted to have children.
HN has an extreme challenge in discussing high-conflict issues. I've pointed this out myself (see: <https://news.ycombinator.com/item?id=30376111>), and it's one of my major frustrations with the site. I do agree with you, strongly, that finding effective ways to break through this communication deadlock should be helpful.
That said, I've also found that the most effective way to counter this is not:
- Complaining, snarking, or even substantively mentioning voting trends. Among other issues, this goes specifically against HN guidelines (<https://news.ycombinator.com/newsguidelines.html>), and even where arguably defensible such comments tend to draw downvotes and flags, largely for the reasons given in HN's guidelines: they make boring reading (and discussion). There's also the fact that HN tends to sort out bad voting / bad comments eventually, though as with most online discussion sites it's strongly influenced by initial comments. That's another reason your top-level comment here was likely flagged and hard: it simply doesn't help resuscitate the discussion.
- Point-by-point rebuttal of myths and falsehoods. "Fisking" (<http://catb.org/jargon/html/F/fisking.html>) might have some validity in scientific argument, though as Einstein noted, if an idea is truly wrong, it takes only one sufficient rebuttal (<https://hsm.stackexchange.com/a/3485>). Cutting to the root of a specious argument is far more effective in my experience.
What I've done, to varying degrees of success, where I see a discussion going off the rails is to take the time to craft a top-level comment addressing what I see as a key, substantive, or under-discussed point, with the hopes of steering discussion back on track. It's not always successful, but it often is, even where I feel that I'm arriving late in the game. Key is to not reply to earlier comments (which amplifies them), or to address downvotes or other noxious behaviours. What I suspect is that there are enough readers of HN who are seeking the sort of comment I'm writing that even late contributions can substantively swing discussion. They key is raise the issues or arguments you think are being underrepresented. That's more work than a casual dismissal, but also far more valuable to HN as a whole.
And of course, climate change has been politicised out the wazoo. Downvoting the bullshit is key, though naturally the bullshitters employ a similar tactic. If this seems egregious, the proper response is message the moderators at hn@ycombinator.com raising the question of possible shilling or voting manipulation. Mods can step in, and HN's ultimate behaviour is a mix of moderation actions by members, staff moderators, and a fair bit of programmatic manipulation. Administrative mods are the ultimate backstop, but they are neither omniscient nor omnipresent and often take actions only after having been contacted directly.
An example of editing a comment of mine after some initial downvotes. I entirely ignored the downvote issue, and merely clarified my intent: <https://news.ycombinator.com/item?id=40673847>
And a rare case of a direct refutation (initially posed as a request for sources / clarification, also on a climate-adjacent topic as it happens). Turns out the OP was sharing some long-debunked bullshit disinfo: <https://news.ycombinator.com/item?id=40664837>
If we can’t sort this out we are all… screwed.