I'm a skeptic by nature. I considered the 70s cooling claims to be little more than media hype at the time, I was too young to have had any formed opinion during the 60s.
As for global warming I think that one issue is that the issue of the warming itself is too often conflated with anthropogenic warming. From what I have been able to see, that there is warming seems well supported by the data, but the amount of warming actually experienced seems much less than the models seem to have predicted. More on this later. Whether the warming is human induced is less clear. One of the problems is that many of the people put forward as "experts" in the field are often nothing of the sort. For example, in Australia two of the most prominent people in the field have been Professor Ross Garnaut who was commissioned by the previous federal government to write a report on climate change and the other is Professor Tim Flannery former head of the Climate Commission, now the Climate Council, after it lost government funding. Both of these gentlemen are highly qualified to talk in their respective fields, Garnaut is an economist and his views on the likely effects of various warming scenarios on the economy are entirely reasonable. Similalry for Flannery, a mammalogist and palaeontologist and quite well qualified to discuss the likely effects of warming on bio systems.
What neither of these gentlemen are qualified to express an opinion on, however, is the cause of the observed warming: in that area they are laymen. This is a major problem that those who are concerned about warming need to address. Many of the most outspoken people WRT global warming are not any more qualified to discuss the causes of it than any other reasonably well educated lay person. There are precious few scientists who actually are properly qualified, such as atmospheric physicists. Whatever their views on the matter may be, they are drowned out by the clamouring hoards. It is a form of group think, no one wants to be seen as being out of step with what they see as the consensus of their contemporaries. It's just easier to investigate, for example and in completely good faith, how global warming might effect some aspect or other of the natural world and produce completely valid results, but just take the issue of the cause of the warming as a given. After all, how can, for example, a scientists working on some small freshwater fish in the Murray Darling Basin possibly asses the validity of anthropogenic warminig, but he can with authority talk about the effects of warming, whatever its cause.
I do not subscibe to the theory that there is some sort of conspiracy amongst the scientific community. I know far too many scientists to fall for that one. I do know, however, that scientists are subject to political pressure, both within their field and from outside (as in from politicians). In my work on freshwater fish I have run into some quite nasty little cliques of people (scientists) who for ideological reasons actively work against conservation efferts that would for exampke result in widespread reintroduction of threatened native fish because they are being proposed by anglers and include the option of eventual limited consumptive access to the resource. They prefer to have a much smaller populations in far more limited locations with an aim of somehow unwinding 200 years of European activity in this country. It's insane. They're actually working against their own stated aims. I don't think they're being malicious, just majorly misguided and blinded by their ideology. So I am not entirely sure that there are not pockets of people like these scientists amongst the climate science community.
Even if they are right, that the warming is anthropogenic, it is obvious that the levels of CO2 are not going to come down anytime soon. We need to be doing far more about learning to adapt to the change rather than doing the King Canute thing. The frantic way that many global warming eperts effectively shout down resonable objections causes me concern. (Mind you, a large proportion of the objections are unreasonable, it's just that ALL objections arer treated the same way.) Statement like "the science is settled" worry me a great deal. Science is never settled. Refusing to even consider that you may be wrong is a typical human characteristic, but one which scientists are supposed to be actively on the look out for and avoiding.
Which brings me to models. I have had a fair amount of involvement in using population models in the management of freshwater fish re-introductions. What became apparent to me was that the models actually only reflected the assumptions that were put into them. They were being treated by the government fisheries managers as the last word in scientifically predicting likely outcomes. As methods of capturing people's knowledge, or at least their opinions, these models work extremely well. What they do not do is discover anything new. A little reflection on this should make this seem obvious, but again it is a case of the scientists involved acting outside their areas of expertise. They may be very knowledgeable about fish, but they are not mathematicians and so tend to believe what the model tells them as a sort of Deux ex machina, without realising that the model is simply reflecting back at them what they told the model. They were convinced the model is right because, funnily enough, it agreed with them. As science and human knowledge overall becomes more complex it is becoming more and more difficult for people to be accross a number of different disciplines. We are becoming a race of specialists with narrower specialties all the time. Maybe we need "specialist" generalists to help us put it all together.
As for climate change, I am concerned that we are taking the wrong path. That may well turn out to bite us on the behind.