> So it's not chaotic like weather is chaotic.

I politely disagree, but my non-expert arguments shouldn't carry much weight. Here's a quote from a 2018 IPCC document instead:

    "The  climate  system  is  a  coupled  non-linear  chaotic  system,
    and therefore the long-term prediction of future climate states
    is not possible.  Rather the focus must be upon the prediction
    of the probability distribution of the system’s future possible
    states  by  the  generation  of  ensembles  of  model  solutions." [0]

I'd kind of like to dive in to the topic of whether an "ensemble of model solutions" is a fair and sufficient sampling of the problem space to trust the statistics, but I don't have enough details. However, I have done particle filters before, and when you have more than a few parameters to estimate, you need a shit-ton of particles before you can trust the statistics you get out. And that's with well behaved and fairly linear systems.

[0] https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-14.pdf