This report of Julia Slingo's recent lecture at the Institute of Physics was originally posted in the discussion forum by a reader. I thought it worthy of elevation to the main blog. My thanks to "Colonel Shotover" for his efforts.
Frances Saunders, president of the Institute of Physics, introduced the lecture, telling us she was particularly delighted to welcome JS, first because her work on climate models showed the importance of physics to everyday life, and second because she was a woman, and so critical in supporting the objective of getting more women into physics. A cynic might suggest that these represented the twin pillars of government science: obtaining funding by demonstrating ‘relevance’ and supporting government policy objectives in return.
JS opened by telling us her lecture wasn’t really about climate change at all, but then showed a couple of slides showing how deadly serious our situation was. The rise in CO2 levels in the atmosphere was unprecedented during the last 800,000 years. Citing John Beddington, she told us that climate change was just one part of a dangerous future, playing into difficulties with water and other resources, population growth, food and energy supplies, politics and economics, health and migration. The planet ought to be ‘pretty much in balance’, but it wasn’t. The Thames barrier had been raised more in 2013/14 than ever before.
So far, so predictable, and I began to regret coming to the lecture. But at that point the tone and subject matter changed entirely. JS put fears about thermageddon to one side and launched into an eloquent disposition on climate models. Her immense enthusiasm for using computerised mathematical models to mimic weather systems was immediately apparent. She described the physics that went into the models, showed us the relevant equations, and talked about her drive towards better resolution, showing us how that increased resolution improved the ability of the models to reflect what happened in the real world. Here was a real scientist, making predictions from models, examining them against reality, investigating discrepancies, striving for an ever better understanding of the way the weather and climate work, immensely proud of how these incredibly complex models could simulate such things as global evaporation and precipitation, and the development of hurricanes. Frequently there were animated graphical comparisons between the models and reality, and we were shown how simulations had improved over the years. There was no alarmism here, although we were shown diagrams showing the absorbtion properties of CO2 and an explanation was given as to why these were important. She was open about problems with current models and that there was an immense amount still to be learned, reflecting this in her final slide: the words of Sir Isaac Newton: “I was like a boy playing on the sea-shore, and diverting myself now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.”
JS needs a certain amount of fear of climate change to keep the funding coming for ever-larger supercomputers, so it’s hardly surprising she’s part of the “consensus”. Nevertheless I came away with a much better opinion of her. She hadn’t shown us much about what climate models tell us about the future, and certainly hadn’t blunted my scepticism about the dire predictions we hear so often. But she had given us a better understanding of how weather and climate models work, accepted that there was much still to be learned, and shown us her passion for continuously improving the models to better reflect the real world.