Simple 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. Read the rest of this entry »