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Madrid 1995 And The Quest For The Mirror In The Sky

The detection of global warming and its attribution to the human cause had always been a task fraught with seemingly irreducible uncertainties. These had not subsided towards the end of 1995 when the pressure was mounting to deliver on political expectations introduced in the late 1980s. In a previous post we considered whether the Nov 1995 IPCC Working Group 1 meeting in Madrid was a tipping point in the corruption of climatology. Here we take a closer look at the science behind the ‘Chapter 8 Controversy’ in a longer essay broken into 2 posts (Part II here).

Mirror, Mirror hanging in the sky
Won’t you look down what’s hap’n here below

Image from Santer's Detection and Attribution presentation, Working Group 1 Plenary, Madrid, Nov 1995

Could this really be it? The first faint image of man in the sky?

Ben Santer had just placed a transparency under the lens to project this colour pattern high upon the conference wall. It was the first afternoon of the Working Group 1 Plenary in Madrid, and this great council of nations from across the entire globe was persuaded to study the significance of its strange contours before getting down to their principle task. And so they should study it, for this is a game-changer striking at the nub of what the IPCC is all about. Although obscure, here is an image of the impact of human industry on the atmosphere above. At least part of the recent warming had at last been attributed to industrial emissions. If not for this, then why these near one hundred delegations flown in from all corners of the globe? There they were carefully positioned at arched rows of labelled bureaus across this cavernous auditorium. As they listened to live translations of Santer’s explanation, not a few of them must have gazed up in wonder: Could this really be what man hath wrought?

The science of Detection and Attribution had come a long way fast, and in recognising the significance of these recent developments the chairman, Sir John Houghton, opened the conference with a surprising change to the agenda. The main purpose of this Working Group 1 Plenary is to consider, modify and unanimously approve—as a faithful synopsis of the entire scientific report—every line of a drafted non-technical summary. To inform this approval process, the lead authors of the chapters would first give a 10 minute overview of their finished chapters and respond to any queries from the delegations. But in addition to this, Houghton proposed a special extended presentation on the Detection and Attribution issue, the subject of the contentious Chapter 8. This was apposite to the great interest and controversy so evidently building around this topic. But it was also necessary, as Santer in his presentation ‘went to considerable lengths to stress,’ because the recent developments in the science ‘justify a stronger statement on attribution’ than was included in the draft Executive Summary that the delegates held in their hands. On this topic, the Executive Summary was entirely out of date. [AustDelRpt]

The pace of Detection and Attribution (D&A) research in the early 1990s was such that the avant garde was evolving way ahead of, and out of pace with, the plodding progress of peer-review publication. Moreover, through 1995 it was becoming clearer that the science had advanced beyond the early drafts of the Second Assessment, from which was drafted the Summary for Policymakers and its Executive Summary. Not only was the research advancing, but a breakthrough had been achieved such that the human signal in the warming could now be observed for the first time emerging above the noise of natural variability.

For the significance of this finding in the history of the IPCC, consider that back in 1990 Tom Wigley had submitted a draft of the First Assessment that was conclusive: The human impact on climate had NOT been detected. And so he was asked: How long before we can expect to see the signal? His response is recorded in the final section of the published Chapter 8. Given expected advances in modelling and another ½ degree of warming, attribution should be achievable. But this much warming is not expected for ‘a decade or more,’ and this assessment was repeated in the Rio Supplement of 1992 [FAR p253-4]. Wigley’s prediction turned out to be wrong because he did not anticipate the breakthrough in the research that was just around the corner. This breakthrough meant that the human signal could be seen even despite the pause in warming of the early 1990s.

Most of the scientists involved in this advanced D&A work were on board as authors contributing to the new Chapter 8. Moreover, its co-ordinating lead author was also the lead author of the two most important recent papers delivering these D&A results, including the one that explains the significance of our ‘Mirror in the Sky’ above.  So here in Madrid, at the final plenary of Working Group 1, Ben Santer was the man. Here was the man leading this advance in the science who was now explaining it directly to those who most needed to know.

As Bert Bolin had just put it in his opening address, the Summary for Policymakers is ‘the scientist’s window into politics.’ And this was the meeting that served to polish that glass. In fact, the first task for the conference was to polish the Executive Summary of the policymakers’ summary—those few pages that the policymakers back home were most likely to look through. The profound policy implications of the proposed updates to this Executive Summary were known to all, and so the idea was that once these advances in the science were explained, the Plenary would agree to seize the day, and incorporate them into a revised Summary.

Santer’s presentation was well received by an overwhelming majority of the delegates who were evidently on side with the proposal to update the report according to this new evidence. An ad hoc ‘small group’ was quickly formed to rewrite the D&A section of the Executive Summary. This group first convened that first evening following Santer’s talk. After much discussion the following day, it managed to deliver a new version of the D&A section for approval at the Plenary on the morning of the 3rd and final day. [AustDelRpt]

What is remarkable about this late intervention is that few people in the world, few scientists—even climate scientists—had seen this representation of the terrible distortion human industry had affected in the sky; few had seen it before Ben Santer placed that transparency under the lens on the first day of Madrid. But by the time he had finished his talk the most important audience in the world evidently understood its significance. This was shaping up as the realisation of a spectacular communion of the most advanced science with inter-national governance—more than the scientist-founders of the inter-governmental panel could have ever anticipated—a marvellous triumph for the communication of knowledge to power, and, in every way, it was happening on a global scale.

A marvel it might have been if it weren’t for those present at the conference with no interest in the message so communicated. One or two delegations with great stake in the continuing growth of the fossil fuel industry seemed to take every opportunity to push back, compromise, slow down, derail, and sabotage a consensus on this issue. And so the triumph at Madrid, later celebrated by Houghton—a triumph of science over vested interests—was challenged on every line, on every word that might so much as suggest attribution of climate change to the human cause. It had been a long journey to Madrid, and even when the word-by-word battle was over on that final desperate night—even when they had just managed to deliver that fateful phase, ‘a discernible human influence’—still the war was not yet won.

We now know that the political war had only just begun. But the question for this blog is not about the politics, but about the science. Had it really triumphed here? Or had it got lost in the enthusiasm for some greater cause?

Full essay, part I & part II