I knew that in the later 1970's the National Academy of Sciences commissioned a report on possible future climate change due to anthropogenic carbon dioxide emission at the request of President Carter's science adviser. The resulting Charney report basically said climate change is happening and gave a reasonably accurate (by today's standards) estimate of what the effects would be.
I didn't know that the NAS report was preceded by a (then secret) report by the JASONs, who had essentially independently come to the same conclusions. A fascinating article on the times online by Naomi Oreskes and Jonathan Renouf spells out the JASON's conclusions:
Right on the first page, the Jasons predicted that carbon dioxide levels in the atmosphere would double from their preindustrial levels by about 2035. Today it’s expected this will happen by about 2050. They suggested that this doubling of carbon dioxide would lead to an average warming across the planet of 2-3C. Again, that’s smack in the middle of today’s predictions. They warned that polar regions would warm by much more than the average, perhaps by as much as 10C or 12C. That prediction is already coming true – last year the Arctic sea ice melted to a new record low. This year may well set another record.
Nor were the Jasons frightened of drawing the obvious conclusions for civilisation: the cause for concern was clear when one noted “the fragility of the world’s crop-producing capacity, particularly in those marginal areas where small alterations in temperature and precipitation can bring about major changes in total productivity”.
Note that the JASONs are not being "alarmist" - they merely highlight that GCC will almost certainly cause widespread economic, social and political disruption, in particular in those countries too poor to mitigate its effects. Such unrest is almost certainly not in the best interests of the United States.
Had the Carter administration's moves toward energy independence and alternative energy sources been followed the world would have had 30 years head start on combating Global Climate Change.
I also didn't know that the Charney report was followed by another report commissioned by the Reagan administration that was elected in 1980. They knew how to deal with reports whose conclusions they didn't like: commission another report and put someone to your liking in charge of it.
Nierenberg’s report was unusual in that individual chapters were written by different authors. Many of these chapters recorded mainstream scientific thinking similar to the Charney and Jason reports. But the key chapter was Nierenberg’s synthesis – which chose largely to ignore the scientific consensus.
[...]
Overall, the synopsis emphasised the positive effects of climate change over the negative, the uncertainty surrounding predictions of future change rather than the emerging consensus and the low end of harmful impact estimates rather than the high end. Faced with this rather benign scenario, adaptation was the key.
If all this sounds familiar, it should. Similar arguments have been used by global warming sceptics ever since Nierenberg first formulated them in 1983. Global warming was duly kicked into the political long grass – a distant problem for another day. At a political level, Nierenberg had won.
But this was only the beginning of his involvement in what eventually became a movement of global warming sceptics. A year after his report came out he became a co-founder of the George C Marshall Institute, one of the leading think tanks that would go on to challenge almost every aspect of the scientific consensus on climate change. Nierenberg hardened his position. He began to argue not just that global warming wasn’t a problem, but also that it wasn’t happening at all. There was no systematic warming trend, the climate was simply going through its normal, natural fluctuations.
The creed that Nierenberg originated all those years ago still has its dwindling band of followers. Sarah Palin, the Republican vice-presidential candidate, recently responded to a question about global warming by saying: “I’m not one who would attribute it to being man-made.”
Because doing so would mean that its would be in the United State's best long-term interests to take actions that would be bad financially for certain polluting mega-corporations.