Ice and the Sky: bubbles of  fossilised time

Garlanded with honours and academic recognition, French paleo-geologist Claude Lorius still says towards the end of this film that he wonders whether his life will make a difference. He wanders elegiacally through rocks only half covered in ice and stands in the rising tide on some distant atoll, emphasising the ice retreat. Luc Jacquet (Oscar-winning director of March of the Penguins) made this documentary-homage to honour the science and, yes, to challenge us make the changes we must face.

 Lorius first went south in 1957, answering a bulletin board ad, to spend a winter snowed in with two other men in a hut about the size of my living room. He was already experienced from research in Greenland, and his research focused on the difference between ‘heavy’ snow and ‘light’ snow, crystals falling at different times of the year and hence creating different kinds of ice. Snowflakes are all unalike, but it seems some are more different than others. He built up the evidence of long cycles of ice-ages and inter-glacial periods which made his thesis in the early 1960’s, a fundamental building block of what came after.

A casual drink of whisky gave him his eureka moment. Some Australian scientists dropped an ancient piece of ice into the water of life and as it cracked, bubbles drifted upwards. Lorius describes the moment in a characteristic way by asking why he had never noticed this before. Those bubbles had been trapped in the ice since it was formed. The ice was thousands of years old. So was the air.

The quest became one of finding the oldest ice, taking it back to his laboratory in Grenoble, and analysing the fossilised air it contained. A lot of the work was done at Dome C, now camp Concordia run jointly by the French and Italians.  The summit is 3200 above sea level and the ice is nearly the oldest on Earth.  Incidentally Walker reports in her tour of research stations that the food (and drink) at the station easily outclassed the rest of the continent. Some clichés are founded in fact. Indeed archival film used in ice and the Sky shows plenty of meals and a white-hatted chef insisting on good service.

Lorius wanted to go further.  To get deeper – and older - he need to go to Vostok, the Russian research station. Vostok is legendary as the coldest place ever reliably recorded on the Earth’s surface, sinking to an extraordinary -89.2°. (The map is from Walker's book.) This was 1984. He not only faced major physical and engineering challenges alongside the techniques needed for pioneering science. There were the diplomatic challenges of the Cold War too. An enduring image of the film is America, Russian and French scientists working together in extreme conditions and celebrating joyously when ice over 400,000 years old was recovered. For many years this was the oldest ice known. The work at Vostok gives us one of the most important graphs in all of climate science.

The air in ice-cores shows the levels of carbon dioxide and methane in the atmosphere at the time the ice was formed. They can relate this to temperature (by the nature of the hydrogen in ‘heavy’ or ‘light’ ice). The graph shows the extraordinarily close correlation between the two. (There’s a great explanation at AntarcticGlaciers.org which is where the graph below is reproduced.)  Walker likens CO2 to curry powder: the atmosphere only needs a pinch to add heat.

Over the last 100 years, since humanity started digging up fossil fuels, burning them and putting the gas into the air, the temperatures have shot up. The graphs clearly show how temperature has increased further and faster than any time in four millennia. Today ice over 800,000 years old has been extracted which confirms the story revealed by Lorius’ research.

Ice and the Sky is a beautiful film. Jacquet and Lorius tell a moving and enlightening story about what is happening to our home. The British Guardian interviewed them at Cannes where the film closed the festival. The discussion which is itself a delight and the two men were all too well aware of the irony of the conspicuous consumption which surrounded them on the Riviera. In keeping with science founded on looking at whisky Jacquet, talking about the challenges of change offers the insight ‘We need desire – this is very important. But you can make a big party sustainable easily.’

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