snowwrestler, it may vary by field, but my (non-climate) field relied almost entirely on informal communications, presentations, write ups being shared but not published.
I don't have direct experience with climatology, but from what I understand it's somewhat similar: conferences like AGU are really important to climatologists for that reason.
To present (even a poster) at a conference like AGU, you have to submit an abstract and it must be accepted by a committee of other scientists. It's not a paper, but still counts as a form of review and publication.
Edit to acknowledge: obviously a lot of work gets done informally during conferences as well.
But it's in the service of publishable research, is it not? I don't think many scientists are going to say, "I'm changing my research program based on something I read on Hacker News yesterday." There's a bar for serious consideration.
I don't have direct experience with climatology, but from what I understand it's somewhat similar: conferences like AGU are really important to climatologists for that reason.