Correction

Today the scientific argument about the broad principles of what we are doing to the Earth’s climate is over. By releasing huge quantities of greenhouse gases such as carbon dioxide and methane into the atmosphere we are warming the world.

Since the early 1990s there has been a furious debate about global warming. So-called climate change “sceptics” have spent years disputing almost every aspect of the scientific consensus on the subject. Their arguments have successfully delayed significant political action to deal with greenhouse gas emissions. Recent research reveals how the roots of this argument stretch back to two hugely influential reports written almost 30 years ago.

These reports involve a secret organisation of American scientists reporting to the US Department of Defense. At the highest levels of the American government, officials pondered whether global warming was a significant new threat to civilisation. They turned for advice to the elite special forces of the scientific world – a shadowy organisation known as Jason. Even today few people have heard of Jason. It was established in 1960 at the height of the cold war when a group of physicists who had helped to develop the atomic bomb proposed a new organisation that would – to quote one of its founders – “inject new ideas into national defence”.

So the Jasons (as they style themselves) were born; a self-selected group of brilliant minds free to think the unthinkable in the knowledge that their work was classified. Membership was by invitation only and they are indeed the cream. Of the roughly 100 Jasons over the years, 11 have won Nobel prizes and 43 have been elected to the US National Academy of Sciences.

For years, being a Jason was just about the best job going in American science. Every summer the Jasons all moved to San Diego in California to devote six weeks to working together. They were paid well and rented houses by the beach. The kids surfed while their dads saved the world. Less James Bond, more Club Med.

Today the Jasons still meet in San Diego in a quaint postwar construction with more than a hint of Thunderbirds about it. In 1977 they got to work on global warming. There was one potential problem. Only a few of them knew anything about climatology. To get a better understanding they relocated for a few days to Boulder, Colorado, the base for NCAR – the National Center for Atmospheric Research – where they heard the latest information on climate change. Then, being physicists, they went back to first principles and decided to build a model of the climate system. Officially it was called Features of Energy-Budget Climate Models: An Example of Weather-Driven Climate Stability, but it was dubbed the Jason Model of the World.

In 1979 they produced their report: coded JSR-78-07 and entitled The Long Term Impact of Atmospheric Carbon Dioxide on Climate. Now, with the benefit of hind-sight, it is remarkable how prescient it was.

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”.

Scientific research has since added detail to the predictions but has not changed the basic forecast. The Jason report was never officially released but was read at the highest levels of the US government. At the White House Office of Science and Technology Policy, Frank Press, science adviser to President Jimmy Carter, asked the National Academy of Sciences for a second opinion. This time from climate scientists.

The academy committee, headed by Jule Charney, a meteorologist from Massachu-setts Institute of Technology (MIT), backed up the Jason conclusions. The Charney report said climate change was on the way and was likely to have big impacts. So by the late 1970s scientists were already confident that they knew what rising carbon dioxide levels would mean for the future. Then politics got in the way. And with it came the birth of climate change scepticism.

In 1980 Ronald Reagan was elected president. He was pro-business and pro-America. He knew the country was already in the environmental dog house because of acid rain. If global warming turned into a big issue, there was only going to be one bad guy. The US was by far the biggest producer of greenhouse gases in the world. If the president wasn’t careful, global warming could become a stick to beat America with.

So Reagan commissioned a third report about global warming from Bill Nierenberg, who had made his name working on the Manhattan Project developing America’s atom bomb. He went on to run the Scripps Institution of Oceanography where he had built up the Climate Research Division. And he was a Jason. 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.

His basic message was “calm down, everybody”. He argued that while climate change would undoubtedly pose challenges for society, this was nothing new. He highlighted the adaptability that had made humans so successful through the centuries. He argued that it would be many years before climate change became a significant problem. And he emphasised that with so much time at our disposal, there was a good chance that technological solutions would be found. “[The] knowledge we can gain in coming years should be more beneficial than a lack of action will be damaging; a programme of action without a programme for learning could be costly and ineffective. [So] our recommendations call for ‘research, monitoring, vigilance and an open mind’.”

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.”

Professor Naomi Oreskes is a historian of science, researching the history of climate change. Dr Jonathan Renouf is producer of Earth: The Climate Wars, 9pm tonight on BBC2

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