You hear similar arguments from those who believe climate change is happening but disagree with current efforts to counter-act it. The logic being that right now climate change is not causing any major harm and that we can't really predict the future so there's no point in worrying about what might happen in a decade or two.

I don't think anyone is arguing that right now climate change or AI is threat to human civilisation. The point is that there are clear trends in place and that those trends are concerning.

On AI specifically, it's fairly easy to see how a slightly more advanced LLM could be a destructive force if it was given an unaligned goal by a malicious actor. For example, a slightly more advanced LLM could hack into critical infrastructure killing or injuring many thousands of people.

In the near-future AI may help us advance biotech research and it could aid in the creation of bioweapons and other destructive capabilities.

Longer-term risks (those maybe a couple of decades out) become much greater and also much harder to predict, but they're worth thinking about and planning for today. For example, what happens when humanity becomes dependant on AI for its labour, or when AI is controlling the majority of our infrastructure?

I disagree but can understand the position that AI safety isn't humanities number one risk or priority right now, however I don't understand the dismissive attitude towards what seems like a clear existential risk when you project a decade or two out.