After the “catastrophe signal’ – When science entered the policy greenhouse

Guest essay by Bernie Lewin

A new book on the origins of the global warming movement tells how the Intergovernmental Panel on Climate Change was first pressed into policy based evidence making.

It was a single line in one report that read:

The balance of evidence suggests a discernible human influence on global climate.

These words in the second assessment of the Intergovernmental Panel on Climate Change can now be seen as pivotal in the history of global warming science.

However tentative the wording, this was the first time that an official assessment had made a positive ‘detection’ claim.

The breakthrough was widely celebrated and then used to justify a change of US policy, towards support for binding greenhouse gas emissions targets.

But this came only after protests over what had been done to the IPCC report to make way for this statement. Just days before the US policy change was announced, an op-ed by leading US scientist, Frederick Seitz, described the late removal of sceptical passages as ‘a major deception’, and a ‘disturbing corruption of the peer-review process’, where policymakers and the public had been misled into believing ‘that the scientific evidence shows human activities are causing global warming’.

For Seitz and others, responsibility for the deception sat with Ben Santer, the coordinating author of the ‘detection’ chapter. However, although it was indeed Santer who had made the changes, it is now clear that he was not acting alone. Instead, there appears to have been an orchestrated campaign to alter the scientific findings so that they could justify the US policy change.

This is most evident in an official US government submission to the IPCC. It was supposed to be suggesting changes only to the wording of the report’s summary, but shows Washington pressuring the IPCC to change the underlying scientific chapter. It asked for recent findings on the effects of sulphate aerosol emissions to be used to justify a ‘smoking gun’ detection claim, and for the removal of uncertainty statements that stood in its way.

The submission was written by Robert Watson, a British chemist who had recently taken up a position in the White House. When previously at NASA, Watson had been at the centre of an earlier scare – over destruction of the ozone layer – where he had shown a deft hand in public relations, keeping scary stories in the headlines so as to maintain pressure for a complete ban on CFCs. By 1989, concern over an ozone ‘hole’ in remote Antarctica had waned, but just before a big ‘Save the Ozone Layer’ conference, Watson declared that Arctic ozone was ‘primed for a large destruction’ in coming days.

Watson knew very well that there was almost no chance of a northern ‘hole’, but his warning had the desired effect, winning headlines around the world and undoubtedly influencing the European’s decision to wind up all production of CFCs.

Scientists’ ability to catalyse policy action did not go unnoticed. By the time of the 1992 Rio ‘Earth Summit’, political attention had shifted towards regulating fossil fuels and many country delegates queued up behind George Bush (senior) to sign a convention to do just that. Still, the US had been holding out on binding commitments to emissions targets. The next year, when Bill Clinton arrived in the White House, change was in the air.

The only trouble was with the science. There was still no hard evidence that emissions were having the effect that the climate models were suggesting. In fact, the IPCC had been retreating further and further from making a ‘detection’ finding. Its first assessment in 1990 warned that detection might not be achieved for decades. A special report for the Rio summit was even more sceptical. By 1995, the scientists were declaring that ‘we don’t know’ when detection might be achieved. This could hardly justify drastic climate action.

The first step towards rectifying the situation involved a claim that sulphate aerosol emissions had been damping warming in recent decades. This is how the climate modellers could explain the lack of recent warming while still predicting a future catastrophe. Still, the argument for detection remained weak.

But then, at the eleventh hour, Santer made a dramatic new discovery. The aerosols effect also distorted the expected geographical pattern of warming, and he claimed to have found this very pattern in the climate data. However, his announcement came after his chapter of the IPCC report had already been drafted and reviewed. While it was agreed to include the new findings, there was heavy and sustained criticism from his peers, and this explains why he retained a very sceptical conclusion.

All that remained was for the country delegates to accept the scientists’ report and agree on a summary at a meeting in Madrid. But it was leading into that meeting, in their comments on the summary, where the US said that the report needed changing. Watson made specific suggestions on how to use Santer’s new findings to support a detection statement. The State Department cover letter was less specific but more insistent, asking ‘that the chapter authors be prevailed upon to modify their text’.

In Madrid, Santer was again invited to explain his discovery. When he declared that his chapter was out of date and needed changing, the Saudis and Kuwaitis protested that the new findings were only preliminary and they also questioned the probity of national delegates changing the text of the scientists’ report. But this was dismissed as the carping and blocking strategies of vested interests; the changes the US wanted were made.

Many years later, Houghton published a reflection on the Madrid meeting under a banner ‘Meetings that changed the world’. As he saw it, without the triumph of science over the oil lobby at that meeting, global action on climate change could not have proceeded to the climate treaty agreed in Kyoto two years later. According to Houghton, passage of the famed ‘discernible human influence’ statement saved the treaty process. Considering its effects on later events it’s hard to disagree. But what is not widely known is that this policy driven finding also saved the IPCC.

Bernie Lewin’s book on origins of the global warming scare, Searching for the Catastrophe Signal, is published by the Global Warming Policy Foundation.