A glacier in the Cairngorms?

Garbh Choire Mor, Cairngorms

The Garbh Choire in July 2011. The false moraine is the ‘lip’ of the coire that can be made out just below the lowest snow

There seems to be something irresistible to many folk about having our very own glacier – even if it’s long gone.

A professor at Dundee University made the headlines this week with a claim that Coire an Lochain in the Cairngorms held a glacier as recently as the 1700s. The news seemed to excite everyone, and I have to admit to a small frisson myself. But why? Okay, 400 or so years ago is a lot more recent than the over 11,000 years conventional wisdom said had passed since the last Scottish glacier had disappeared but, all the same, it’s not as though we could go and poke it with an ice axe. Gone is gone, whether it’s 11,000 years or 400.

Anyway, the controversy opened up quickly when, writing the story up for the MCofS website, I asked the opinion of Adam Watson on the claims. He dismissed them as poorly researched and tested and said that if there was a ‘little ice age’ glacier in Scotland – which there wasn’t – it would have been in the Garbh Choire Mor, where, unlike Coire an Lochain, snows still lie through most summers.

Sphinx snow patch, Garbh Choire

The Sphinx snow patch in the Garbh Choire

But: the claims first:

Dr Martin Kirkbride, a geographer at Dundee University, said in his paper that Scotland’s most recent glacier – formed during the ‘Little Ice Age’ – possibly existed in the Cairngorms as recently as the 1700s.

He said it had long been understood that Britain’s last glaciers melted around 11,500 years ago, but that, by using modern dating techniques, he had shown that a small glacier had been formed in Coire an Lochain in the Northern Corries and had piled up granite boulders to form moraine ridges within the last few centuries.

He said: “Our laboratory dating indicates that the moraines were formed within the last couple of thousand years, which shows that a Scottish glacier existed more recently than we had previously thought.

“The climate of the last few millennia was at its most severe between 1650 and 1790. There are some anecdotal reports from that time of snow covering some of the mountain tops year-round. What we have now is the scientific evidence that there was indeed a glacier.”

Dr Kirkbride’s paper was backed by another from Dr Stephan Harrison at the University of Exeter and Dr Anne Rowan at the University of Aberystwyth, who developed a climate model to simulate Little Ice Age climate in the Cairngorms. Their paper argued that small glaciers would have been created in the corries by a cooling of air temperatures by 1.5C and precipitation increasing by ten per cent.”

Dr Harrison said: “Our findings show that the Cairngorm mountains were probably home to a number of small glaciers during the last few hundred years – around 11,000 years later than previous evidence has suggested.”

However, the claims of both sets of scientists were rejected by Dr Adam Watson, primarily an ecologist but who has made particular study of snow and long-lying snow beds in Scotland and in the Cairngorms in particular.

A chapter in his fascinating book, ‘A Snow Book, Northern Scotland’, based on over 70 years of observations and study, specifically deals with the 18th century glacier question and he is in no doubt that such a thing didn’t exist, the boulder moraines often claimed as evidence actually being built up by rockfall and avalanche debris.

To be fair, his chapter involved the Garbh Choire rather than Coire an Lochain but, after reading both papers, he said this week that one boulder ridge identified by Dr Kirkbride as a moraine (pushed up by a glacier) was, in fact, a protalus rampart, fed annually by boulders, soil, vegetation and other debris coming down in avalanches.

He said: “In areas of acidic bedrock, such as the granite of the Cairngorms, a moraine has a clearly defined profile with different soil horizons. These include very thin acidic dark horizons above a dark greyish horizon (all these combined often called ‘topsoil’ by laymen), above a strongly coloured orange-brown sandy or gravelly ‘subsoil’. Other glacial deposits, till or boulder clay under the glacier and fluvio-glacial deposits washed out by glacial rivers, have their own characteristic horizons. This differentiates them more clearly and reliably than any surface measurements by geomorphologists.”

He said the Kirkbride paper was typical of studies by geomorphologists “who fail to dig a single soil pit and ignore fundamental principles of soil science.”

And he added: “This failure includes Sugden, who made the original proposal of glaciers in several corries of the Cairngorms in the 1700s and one in Garbh Choire Mor in the early 1800s.

“Both the 2014 papers state clearly that there was no soil profile in the supposed morainic ridges that they described. This rules out moraines without further ado.

“Both papers are uncritical in dismissing the possibility of protalus ramparts on the basis of the authors’ personal opinions on the unlikelihood of boulders and other debris travelling so far in avalanches. This signifies that they have never witnessed avalanches in these corries or their aftermath that can be seen in photographs.”

And he concluded: “The claim in Kirkbride about moraines in Coire an Lochain of Cairn Gorm is particularly unlikely. A snow patch survives till winter during very few years in that corrie, whereas in Garbh Choire Mor the patches almost always survive till winter, and hence this is the most likely site for a glacier in Scotland.”

However, Dr Kirkbride has stood by his paper.

He said: “I don’t have Adam’s experience of the Cairngorms – I doubt anybody does. But I have been visiting the Cairngorms for over 30 years, in all seasons, and I share his appreciation of the role of avalanches in modifying the landscape. Before writing our paper, we carefully considered several possible explanations for the boulder ridges before interpreting them, on the balance of a variety of evidence, as glacial moraines.

“The key point with regard to the moraine ridges that we describe in our paper is that the larger avalanches actually start at this height in the corrie, and move boulders from here further down the slope. The glacier has deposited the boulder ridges in a different place from where the avalanches do: in fact, it’s snow avalanches in springtime which are gradually destroying the glacial moraines at the present day by eroding debris from them, not creating them.

“The ridges themselves are in the wrong orientation with respect to the cliff above to have been deposited by snow avalanches, as we explain in our paper.”

Dr Kirkbride said he agreed that further work on soil profiles would be useful, but said it was not true that he didn’t dig a soil pit to examine this. “The deposits are not old enough to have well-developed soil profiles on them, unlike the 12,000 year-old moraines elsewhere in the Cairngorm corries,” he said.

So there you have it: a clash of experts. Though Adam Watson is primarily known as an ecologist rather than a glaciologist, he brings a scientific rigour to the question (especially when you read the full Chapter 6 of his book) which is hard to argue with. But who’s to gainsay the expertise of Drs Kirkbride etc? I don’t think they hand out university professorships in lucky bags.

I suppose an ideal outcome would be for the two men to work together, bringing each of their expertise to the table and producing a joint paper. Maybe that would seem too much of a duel, with a winner and a loser, but I’d hope that both men are bigger than that and would be more interested in settling a question that clearly fascinates people.

Great. Settled. Now all they need is the time…

Since writing this post I’ve found a very apposite article on the ukHillwalking site, written by Dr Kirkbride and one of his colleagues, answering Dr Watson’s criticisms. It’s very worthwhile reading and can be viewed here.

And, at the risk of endless scientific duelling, here’s a more complete version of Adam Watson’s argument: http://www.winterhighland.info/forum/read.php?2,160860,160987#msg-160987

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13 Responses to A glacier in the Cairngorms?

  1. Interesting debate, although the argument that a glacier is more likely to have been in Garbh Choire Mor seems the more logical don’t you think?

    • I spoke to Dr Kirkbride on the phone and his argument (which I didn’t retain sufficiently to accurately reproduce here) was that the topography of the two coires (which is very different) was what made the difference. But there does seem to be considerable polarisation of ideas on this debate and I’m in no way qualified to judge who is right. (Keep up your own blog, by the way. 🙂 )

  2. Stephan says:

    I’m the first author on the modelling paper, and it’s pretty clear to us that Martin Kirkbride is right about this. There is little chance of the ridges at Coire an Lochain being protalus ramparts. Both Martin and Doug Benn (also on his paper) are acknowledged experts on PTRs and the ridges are in the wrong position for this.

    It seems to me that the previous existence of LIA glaciers is pretty uncontroversial. Intuitively, it’s not hard to imagine small glaciers in Cairngorm corries at a time when the Thames was freezing over, and when snow patches were lasting until late summer in the Cotswolds of southern England. Given the late lying snow patches now at a time of considerable global warmth, it seems clear these these must have been much bigger in the past. Our modelling shows that such sites are very sensitive to small changes in MAT and precipitation, with only a drop of -1.5C producing substantial glaciers (although the model is allowed to run to equilibrium).

    What with Martin’s cosmogenic dates and the geomorphology of the sites, I think the evidence is compelling.

  3. Martin Rye says:

    Interesting stuff. That Moraine is a way down the mountain side and needs to be explained. They do need to team up and investigate. Really excellent post and thanks for writing it up.

  4. Some good counters in that extra link! The explanation for the lack of snow in Coire an Lochain also sounds logical, haha! I wonder if Watson will reply…

  5. Bob McChristie says:

    This is very interesting – and shows how two different viewpoints become polarised – strangely enough in Dr Kirkbride response he talks about observations on six continents – now he and his colleagues may have only carried out observations on six continents – but there is argument about whether there are seven continents QED

  6. Stephan says:

    Just read Dr Watson’s comments on Winterhighland. He clearly hasn’t read our paper carefully and in various places accuses us and Martin’s team of immaturity and failure to understand the nature of the scientific process. This is pretty patronising stuff in my opinion. I don’t want to engage in a slagging match, but any cursory examination of the CVs of the scientists involved in the two papers shows a very high level of scientific expertise in mountain and glacial geomorphology and numerical modelling, with substantial research experience all over the world. We do not have the ecological expertise of Dr Watson, but this isn’t an issue about ecology. Ours was a modelling paper which showed that even small reductions in MAAT produced substantial cirque glaciers in a number of areas. Our job was not to dig holes in moraines, and even if we had it would not have provided the evidence to test the hypothesis one way or another. Dr Watson argues that the ridge in Garbh Coire Mor is a protalus rampart on the basis of boulder angularity, arguing that boulders would be rounded by glacial action. This shows a failure to understand how small glaciers work. However, the essential question is this: is it reasonable to suppose that during the LIA the Cairngorms were around 1.5C cooler than now? If so, then our modelling suggests that glaciers would have developed, although the exact size of the glaciers would have been partly limited by the length of time that conducive conditions prevailed.

    As cairngormwanderer say above, blogs aren’t the best places to argue these things. If Dr Watson (and/or others) would like to respond formally to our papers in the journal then I’m sure we would all look forward to this.

  7. To be honest I think scientific discussions on blogs make the science closer to normal people, don’t you think? 🙂

    Anyway, it was a pleasure to read the post and your comments. I have never visited Scotland, but as a glaciologist I am exploring the issue to write few lines about it on my own blog. To me, the paper of Kirkbride et al. seems to be reasonable and I agree with Stephan that it is not an case of ecology, but purely geomorphology, glaciology and climatology.

  8. mwhite says:

    “Glacier-like hazards found on Ben Nevis”

    http://www.bbc.co.uk/news/uk-scotland-highlands-islands-28885119

    “On these fields, they have come across compacted, dense, ice hard snow call neve.

    Neve is the first stage in the formation of glaciers, the team said.

    The team has also encountered sheets of snow weighing hundreds of tonnes and tunnels and fissures known as bergschrunds.

    The large, deep cracks in the ice are found at the top of glaciers.”

    • The BBC reporter was being a wee bit credulous there. There was certainly a lot of snow last winter, and lots has survived, but none of these features are exactly unusual in Scotland and certainly don’t mean we have a glacier starting.

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