First, the number of highly visible global events caused by GW will be coming fast and furious. If the tipping point for societal awareness and acceptance of human induced GW is not already here, it will be in the next year or so.
Unfortunately, all the "boy who cried 'Global Warming'" theatrics with which we've been bombarded the last few years will make it much harder for actual evidence to be even alarming, let alone convincing.
I read an article a few days ago about a species of jellyfish which had just been seen in a new area. The headline confidently blared that GW was the cause of the spread of this creature's range. The article itself didn't say anything about it, though, except to quote some Eminent Man saying that the jellyfish was sensitive to temperature, and guessing that something might perhaps have warmed the water in the area where the little bugger had just been found. He didn't mention anything about actual measurements of water temperatures - a curious omission.
Now this only counts as a "highly visible" event to those of us who take an interest in things like marine invertebrates. Jellyfish are sensitive to a lot more than temperature; salinity, wind & water currents, parasites, presence of food, etc. And, perhaps more importantly, randomness. Jellyfish don't appear like mosquitos at certain times of the year - some years they don't appear at all, other years we're buried in them. This I know to be the case from my own observations of jellyfish over many years - I don't need some geek reporter or pop musician to tell me about the habits of jellyfish. The Eminent Man would of course know all that, and he wasn't dumb enough to drag GW into it himself. But the reporter certainly was dumb enough. So we have yet another alarm with nothing
at all behind it. It's deteriorated to the point that it's a mere pleasantry, down there with the usual casual, everyday gripes about the weather - after this year, the phrase "global warming" is going to mean a serious cold snap. It's gone from panic to joke, all without serious evidence and coherent argument ever even being presented. The more we're bombarded with blatant PR and political bloviation, the further we'll have to travel before even serious evidence is taken seriously.
This is an obvious consequence of the effort to substitute enthusiasm for science. It's been done before, but it never works well.