It was very warm in the room and Constanza Calderón was having difficulty concentrating. She remembered that she had started looking into the whole question of glacier movements several months ago after Bill Shepherd had drawn her attention to an article in 2002 by Roger J. Braithwaite in Progress in Physical Geography 26, Number 1 entitled Glacier Mass Balance, the first 50 years of international monitoring. The article had concluded that there was ‘no obvious common global trend of increasing glacier melt in recent years.’

Shepherd was addressing the whole group. ‘Does anyone know how many glaciers we are talking about?’ Someone said two dozen. Someone else suggested two hundred. ‘Tom? You’re a Californian. How many in your state?’ A satisfied smile spread across Thomas Naylor’s face. His bruised ego was about to get a boost. He felt grateful to Bill Shepherd for asking.

'According to Raub in 1980 there are 497 glaciers. A recent book Glaciers of California by Guyton counted 108 glaciers and 401 glacierets.’ He could see Shepherd was impressed. ‘Thank you Tom.’ Shepherd said with a warm smile. ‘Yes. There are a lot of glaciers in the world…one hundred and sixty thousand at the last count. About sixty-seven thousand have been inventoried but only a few have been studied with any care.'

‘There is Mass Balance Data extending five years or more for only seventy-nine glaciers in the entire world. So how can anyone say they are all melting? Nobody knows if they are or not. Which is why so much is made of particular glaciers…like Kilimanjaro.’ ‘Absolutely,’ said Naylor. ‘Kilimanjaro is definitely melting. Everybody knows that.’ ‘Why is that?’ Shepherd asked. Several people in the group said ‘Global Warming.’

'Actually probably not,’ Shepherd said. ‘Kilimanjaro has been rapidly melting since the 1800s…long before Global Warming. The loss of the glacier has been a topic of scholarly concern for over a hundred years. And it has always been something of a mystery because Kilimanjaro is an equatorial volcano so it exists in a warm region. Satellite measurements of that region show no warming trend at the altitude of the Kilimanjaro glacier. So why is it melting?’

A tall bearded gentleman at the back of the group responded. ‘It’s beginning to look like deforestation is the culprit. I have just come back from Nairobi and was talking to a couple of Swedish scientists at the Norfolk Hotel. They are working out what to do about it. The rain forest at the base of the mountain has been cut down so the air blowing upward is no longer moist. Annika reckoned that if the forest is replanted the glacier will grow again. Göran agreed.’

‘Right,’ said Shepherd. ‘And this is something of a trend. Local Weather and not Global Warming is the principal influence on glacier behaviour.’ An earnest-looking young woman asked for references about Kilimanjaro. ‘Yes. Correct me if I’m wrong.’ He looked across at the bearded gentleman. ‘Betsy Mason’s article in the November 2003 issue of Nature...African Ice Under Wraps. The debate continues in the International Journal of Climatology…’ He looked across at Constanza. ‘Here is my glacier expert.’

‘Yes that’s right,’ Calderón said. ‘2004, Number 24 pages 329 to 339…an article entitled Modern Glacier Retreat on Kilimanjaro as evidence of climate change: observations and facts authored by Kaser and others.’ The young woman scribbled furiously into her notebook. ‘This article shifted the whole debate because Kilimanjaro and its vanishing glaciers have become an icon for Global Warming. This is part of the problem.’ ‘What do you mean?’ the young woman asked. ‘Aah,’ Calderón thought…a journalist.’

‘Politicians lag behind the Environmentalists who lag behind the Scientists who lag behind the latest Scientific Findings. Kaser’s work established that there was a drastic drop in atmospheric moisture at the end of the 19th century. The ensuing drier climate conditions could be forcing glacier retreat.’

…extracted from a Tavern Talk on Climate with Bill Shepherd.