I’d like to make a few points:

Firstly, call me a cynic, but I think the desal plant go-ahead had a lot more to do with the State Govt attempting to placate private interests involved in the project than any foresight as regards to climate change (CC). The “carbon cost” of constructing, and then running the desal plant will hardly be a good thing in terms of carbon emmisions (however many trees are planted or green energy bought to offset the impact. The idea that you can forget about Co2 emmisions involved in manufacture and operation, and simply throw money at carbon credits in order to make it “green”, is not exactly the imaginative approach govts need to take at this time, but I digress.) What happened to recycling?

Secondly, the reason it is beyond the capacity of our social institutions to deal with CC because they exist within an all-encompassing socially-irrational economic institution! Not only does “co-operative” not compute, neither does the very notion of a “society” or “social interests”.
The defining feature of social and economic organisation that has permitted climate change to become a larger and larger problem is the capitalist system, namely the primacy of profit-making above rational social planning. As you point out, any possibility of maintaining the former with the latter with respect to climate-change evaporated about 30 years ago. It is arguably no surprise that no action was taken at that crucial time, given the obvious influence the profit system has on the political sphere.

Basically, the issue of Climate Change presents itself as the failure a system that privileges short-term profit to deal with a serious long-term social and environmental problem. It is a blatantly socially and environmentally irrational way of organising. The first step to solving it will be understanding that “teh economy” is a means to society’s ends, rather than the other way around. Which by necessity means popular control, rather than consensual regulation of a profit-system, a band-aid solution at best.

The biggest ideological challenge (in both capitalist responses to CC and towards non-capitalist responses) will be the anti-government, free-market worshippers and faux-intellectuals, whose ideals do not even admit to the existence of society, let alone problems that might face it.

We may see more dictatorships in a world gripped by the effects of climate change, but it will not be a result of dire need to solve the problem, but the dire need to save the system that is causing the problem.

I hope I haven’t sounded too dogmatic. I suppose one is bound to when capitalism or profit is mentioned more than once, such is the evilness of referring to them without adoration or respect.