The man who got the world to agree on climate

• This is part two of a two-part post. Read part one here.

When not tackling climate science or negotiations Bert Bolin liked nothing more than a little choir singing. Credit: KVA

In 1975, advised by Bert Bolin, the Swedish government drafted a bill on future energy policy containing a conclusion that elsewhere might be controversial even today. “It is likely that climatic concerns will limit the burning of fossil fuels rather than the size of the natural resources,” it foresaw. Produced thanks to Bert’s early role tackling environmental issues, it was one of the first times humans’ effect on climate and the risk it poses us was noted officially. For more than two decades afterward the Stockholm University researcher would further strengthen that case, both through his research and by putting climate science firmly on the political agenda. And those tireless efforts would help the United Nations’ Intergovernmental Panel on Climate Change (UN IPCC) to consistently achieve what otherwise might have been impossible agreements.

The Swedish bill was a bold statement, given that average air temperatures were only just about to reverse a slight cooling that had gone on since 1940. Bert and scientists like Dave Keeling had shown that CO2 levels in the atmosphere were rising. Basic science established by Svante Arrhenius 80 years before had showed this should warm Earth’s surface. So why was it cooling? The way scientists found the answer was typical of the progress in climate science Bert was overseeing. They would use the latest tools, including computers and satellites, bringing theory and measurement together to improve our understanding.

Climate models in the early 1970s were still simple by today’s standards, but had advanced from the early computerised weather predictions Bert had previously pioneered. And when Columbia University’s Stephen Schneider and S. Ichtiaque Rasool added aerosols of floating dust to CO2 in a model for the first time, they found a possible explanation for the temperature drop. The aerosols, particularly human pollution, created a cooling effect that swamped the warming – so much so they warned it could trigger an ice age. Though Stephen and Ichtiaque soon realised that their model overestimated the cooling, aerosols obviously deserved a closer look.

To clear up such murky problems, the Global Atmospheric Research Programme (GARP) that Bert jointly set up would bring together scientists from around the world, despite the cold war. As GARP’s first experiments, looking at heat and moisture flow between the atmosphere and ocean, started in 1974, Bert organised a meeting in Stockholm on climate physics and modelling. GARP had two goals – improving 6-10 day weather forecasts first, and climate change predictions second. As it gradually became clear how hard the first was, climate forecasting became more important.

Diplomacy was needed among the gathered scientists as arguments flared over how ambitious they should be. Should they strive for satellites that could collect the high resolution data scientists and models needed, even though that was beyond their capabilities at the time? And significantly for later climate work – should they seek to produce results so society could respond to change, even when results were uncertain? Bert was clear on that one: scientists had to answer socially important questions, though he was in a very small minority prepared to say so openly.

Unmasking warming

Before flue-gas desulphurisation was installed, the emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide. This pollution partly masked the warming driven by CO2 from 1940-1975, while also causing poor air quality and acid rain. Credit: US National Parks Service

Meanwhile, continuing his research into how long chemicals stayed in the atmosphere, in 1976 Bert used air quality data from the US and Europe to show aerosols dimmed sunlight. That provided physical evidence that the effect mostly happened around polluted cities, and the cooling was much lower than in Stephen and Ichtiaque’s model. And as we’ve cleared up that kind of pollution, CO2’s warming power has been unleashed. Bert was also becoming increasingly interested in how non-human life, like plants and trees, affected climate, reflecting a shift happening in climate science generally. Scientists from ever more subject areas were adding their views, captured by a new sister organisation to GARP – the Scientific Committee on Problems of the Environment (SCOPE). Through the 1970s and 1980s Bert would edit key SCOPE reports on the carbon cycle and greenhouse effect.

Though GARP and SCOPE were boosting the science, Bert wanted their messages to go further. “The outreach from the scientific community to society and politicians was still hesitant and unsatisfactory,” he later recalled. A desire for a more permanent international collaboration on climate research saw GARP evolve into the World Climate Research Programme (WCRP). Yet Bert still wanted a more comprehensive analysis. “After the completion of the first international assessment in 1980 I felt that it was essential that the next assessment should be more truly international and go beyond the physical aspects of climate change that had dominated the efforts so far,” he wrote.

In 1983, Bert began a project supported by the United Nations (UN) Environment Programme to answer that need, leading to the creation of the International Geosphere–Biosphere Programme (IGBP) in 1986. It integrated physical, chemical and biological views of Earth’s ecosystem more closely than ever before. Bert was especially important in realising how hard it would be to get scientists from different areas to work together, and figuring out how to make it work.

“But an organ that provided an international meeting place for scientists and politicians to take responsibility for assessing the available knowledge concerning global climate change and its possible socio-economic implications was missing,” Bert would admit. And in 1987, a stark report called ‘Our Common Future’ would push the UN to create just such a body. Bert, fresh from serving as science advisor to the Swedish Prime Minister, attended the new UN Intergovernmental Panel on Climate Change (IPCC)’s first meeting in November 1988. With no notice, he was asked to serve as chairman – a role that he would continue and cultivate for another decade, even after retiring from Stockholm University in 1991.

Bert Bolin addressing the UN in Geneva, Switzerland, in 1996, where the findings of the IPCC’s second report were formally accepted. Credit: IISD.

At first some scientists like Stephen Schneider thought the IPCC a waste of time, and that existing assessments largely backed by rich countries were thorough enough. “But how many of those are convincing to people in India or Indonesia or developing countries who don’t trust the science that comes out of it?” Bert replied. Eventually seeing the need for worldwide agreement Stephen, like most others, was convinced. From just 28 countries at that first meeting, the IPCC grew to be the largest international scientific project ever, with Bert directing its first two reports, published in 1990 and 1995.

‘Contacting’ heads together

The mazy progress and the heated debates that led to the IPCC’s creation would only get worse as more countries joined and its importance grew. But aided by Bert’s decades of experience – and Sweden’s reputation for neutrality – it succeeded in laying plain the facts, certainties and uncertainties. “His reputation as a brilliant and honest scientist, who listened to and respected diverse views, attracted the best and the brightest of the scientific community to the IPCC, and the fledgling panel rapidly gained the attention of the politicians to whom its reports were addressed,” recalled Bob Watson, who succeeded Bert as IPCC chair. “Bolin’s quiet, soft-spoken style earned him the trust and respect not just of government officials who already recognized the threat of human-induced climate change, but also of those who vehemently challenged the idea that Earth’s climate was even changing, let alone whether humans were involved.”

To Bert’s keen political sense fossil fuel producers would obviously have been the least likely to agree that emitting CO2 was harmful. And he often had to deal with their objections at the plenary sessions where the IPCC’s reports have to be unanimously agreed by all countries. For example, in the IPCC’s second assessment report, the topic of ‘fingerprints’ that can only have been made by human-caused climate change proved particularly controversial. The chapter’s wording said that one especially important fingerprint – cooling higher up when the lower atmosphere is warming – showed a ‘discernible’ human influence.

The delegation from Saudi Arabia objected loudly, backed by Kuwait, before Kenya suggested dropping the chapter altogether. Bert called for a ‘contact group’, where the opposing sides would meet face to face. Commonly used at the IPCC, in the close confines of such contact groups it’s harder to deny the truth, and an agreement is usually reached. This time the Saudis didn’t turn up, and back in the plenary they continued their objections. But the single Kenyan delegate had gone, and his speech resolved the dispute. “I was convinced by the Saudi concerns that this was the most important issue we faced, so I went to the contact group for hours,” he said. “When I understood what was happening, I became fully convinced the lead authors had correctly portrayed the science, and thus I withdraw my objection to Chapter 8 and move we accept the text from the contact group.”

Bert Bolin and his partner Monika Kjellstrand in Henning Rohde’s apartment on the day the IPCC and Al Gore received their Nobel Peace Prize, December 10, 2007. Image copyright Tellus B, used via Creative Commons license, see Rodhe paper referenced below.

The first IPCC reports swayed politicians towards signing the climate change convention at the 1992 Earth summit in Rio de Janeiro, Brazil, to prevent ‘dangerous manmade climate change’. It was the same with the 1997 Kyoto protocol to begin cutting emissions. Even after Bert retired, when some scientists suggested that 550 parts per million (ppm) of CO2 in the atmosphere, twice pre-industrial levels, might be acceptable, he objected. Bert’s view prevails and 450 ppm is now seen as the level where climate change will get dangerous.

When the IPCC received its Nobel Peace Prize on December 10 2007, Bert was suffering from stomach cancer, making him too ill to travel. Among the speeches, co-prize winner US vice-president Al Gore sent the veteran scientist a personal message. “Bert, without you we would not have come to where we are today.” Bert, watching the ceremony on TV in his long-time colleague Henning Rodhe’s living room, answered back. Henning wrote: “It was a very special moment for me and my wife to be with [Bert] on this important occasion and to hear him commenting on the speeches of Al Gore and Rajendra Pachauri – the current chairman of IPCC.”  Bert died less than three weeks later, aged 82, though he had more to say on climate. Three days afterwards a Swedish newspaper published his final letter, whose title ‘Serious but not hopeless’ still describes the climate situation well.

Further reading:

This year I’ve already written about the following pivotal climate scientists who came before Bert Bolin, or were around at the same time: Svante Arrhenius, Milutin Milanković, Guy Callendar part I, Guy Callendar part II, Hans Suess, Willi Dansgaard, Dave Keeling part I, Dave Keeling part II, Wally Broecker part I, Wally Broecker part II, Bert Bolin part I

Bert Bolin’s ‘A History of the Science and Politics of Climate Change’ includes his description of how he has fitted into the story.

The story of Bert’s encounters with Stephen Schneider and the ‘fingerprint’ episode come from Stephen Schneider’s book ‘Science as a Contact Sport‘.

Bert Bolin and Robert J. Charlson (1976). On the Role of the Tropospheric Sulfur Cycle in the Shortwave Radiative Climate of the Earth Ambio : 10.2307/4312172
Bob Watson (2008). Obituary: Bert Bolin (1925–2008) Nature DOI: 10.1038/451642a
Henning Rodhe (2013). Bert Bolin (1925–2007) – a world leading climate scientist and science organiser Tellus B DOI: 10.3402/tellusb.v65i0.20583

Spencer Weart’s book, ‘The Discovery of Global Warming’ has been the starting point for this series of blog posts on scientists who played leading roles in climate science.