On coracles, Partridge, the Mandan and the Inuit

A Passamaquoddy Legend:

In ancient days Partridge was the canoe-builder for the other birds. And after he had finished all the canoes, he called the birds together and each got into its bark and paddled off.

Oh, it was a great sight! First of all came the Eagle, in his big shell, paddling with the ends of his wings. Then came the Owl dipping his wings in the water, like the Eagle. Then the Crane, the Bluebird, the Robin, the Blackbird and the Snipe went sailing proudly after, uttering shrill cries or whistling and singing. And last of all came the tiny Hummingbird in a very tiny canoe; and for him good Partridge had made a prettily little paddle.

And the Fish-Hawk, who lives on the wing, skimmed over their heads, crying with amazement, as he saw the proud little fleet of canoes put out to sea.

“Why, O Partridge,” cried the Fish-Hawk, “have you no canoe for yourself?” But Partridge gave no answer, only looked mysterious and drummed; and the noise of his drumming sounded like an Indian at work on a canoe.

Then the birds sailed back to land, and all cried out, “Why, O Partridge, have you made no canoe for yourself?”

But Partridge shook his head, and said that when he built a canoe for himself, it should be a wonder such as no bird’s eye had ever beheld. This went on for some time until at last every bird knew that Partridge was making a wonderful boat for himself.

Now Partridge thought, “If a boat with two ends sails two ways, when then a boat, that is round, will sail every way.” So he built a canoe like a nest, perfectly round. And when it was finished, he called together all the birds to watch him put out to sea. And as they looked at the round canoe, they all cried out: “What a wonderful boat! We were not wise enough to think of such a thing!”

The Partridge, swelling with pride, stepped into the canoe, and dipped his paddle, But the boat made no headway at all, only spun around and around. And the harder he worked, dipping his paddle, first on one side and then on the other, the faster spun the canoe.

And when the birds saw what was happening, they fell to laughing, and mocking Partridge. And he left his round canoe, and, flying inland, hid himself for very shame under the low bushes.

And to this day he flies close to the ground, and hides under leaves and bushes. And the noise of his drumming sounds far and near like an Indian making a canoe.

Partidge had not been to Wales, nor to India, among other places where coracles are common.

Figure 1. Welsh coracle (Data Wales )

Figure 2. Indian coracle (Wikipedia )

It was in part the presence of the coracle that suggested to Meriwether Lewis as he and William Clark met the Mandan Indian tribe in what is now Washburn North Dakota that the tribe might have been descended from Prince Madoc ap Owain Gwynedd of Wales who lived around 800 years ago. (And would have travelled to America in roughly the same time frame as those reported to have left the Viking boats in Minnesota). It is, unfortunately, not something that can easily be checked with DNA testing, although, as an aside, it is now possible to get paternity testing in the Mandan region of the country. The last full-blooded Mandan, Mattie Grinnell, is reported to have died in 1971. Even by the time of the Lewis and Clark visit the tribe had been reduced from perhaps 15,000 individuals living in 9 villages, down to just two villages of around 1,200 people.

Figure 3. Mandan village – Bull Dance – George Carlin 1832 (American Art )

The village and tribe that Lewis and Clark met were largely wiped out in a smallpox outbreak in 1837. After the epidemic there were only around 100 survivors.

One of the difficulties in getting a true picture of the history of the Native American population prior to the large-scale migrations of Europeans across the continent, is that so many in those tribes died, due to the diseases that also arrived at that time. For example, by the time that the Pilgrims landed in Massachusetts it has been suggested that over 90% of the local native tribes had died, due to infection. (h/t Gregory ) Until recently the major cause of death was thought to be due to smallpox and viral hepatitis , a disease to which Native Americans are more susceptible but leptospirosis has also been now indicted, in the three to six year period that saw the majority of the deaths. Rats and mice from the many ships from different nations that were by that time visiting the continent would contaminate the environment in a way that made locals more susceptible, because of their lifestyle, than the booted and western-oriented visitors.

Regardless of cause, the diseases killed a dominant portion of the population, numbers suggested ranging from 75% to the 98% loss of the Mandan. The enforced migrations of the tribes, and the re-development of the land to fit European farming tradition has also lost a considerable part of the archeological record.

Further, when one goes back to around historic periods measured in tens of thousands of years ago, the maintenance of lineage lines and their origin becomes more difficult, and the need for larger sample sizes to draw realistic conclusions is offset by the reality that if the natives of the time lived on the coast-line, that region, around the world is now under considerable depth of water as the great glaciers have melted.

Yet the lack of evidence should not be considered equivalent to there being no evidence, and thence that these events did not take place. The evidence that the X variation in mtDNA migrated west seems conclusive, as Stanford and Bradley (S&B)have shown.

Figure 4. Distribution of the X mtDNA variation in the global population (Stanford and Bradley).

Having myself, in earlier times, studied how an early Stonehenge was made, after helping make one, the intelligence, and the long time over which events had time to occur back in those millennia, sometimes seems to get lost in current discussions over whether certain journeys and developments could have taken place.

S&B’s argument that local inhabitants of Siberia would, to have been able to survive, had to learn to create sealed clothing from animal/marine sources is a logical base on which to assume that boats, ubiquitous in other parts of the world, would have also existed in the far North. The example of the Thule Inuit, who travelled from Alaska to Greenland during the Medieval Warming Period, arriving in time to greet the Vikings and come down to us as the “skraelings” is well documented. The migration is generally thought to have been motivated by following the whale. It is a distance of on the order of 3,000 miles and while, at one time it was thought that this migration might have taken decades, or centuries there is now a school of thought that it might have occurred within a 2-3 year period, due to the use of dog-sleds and umiaks. The alternative reason that is now proposed for the short duration of the transition is also novel:

the Bering Strait Thule experienced a serious iron shortage related to disruptions in East Asian trade routes after the rise of Ghengis Khan in the 13th century. Knowing of sources of iron in the Canadian Arctic, Thule migrants set off on a journey eastwards in search of this precious commodity. The iron they eventually discovered would have been both meteoric (Cape York meteors) and European, because Norse Greenlanders were trading into the Eastern Canadian Arctic in their quest for walrus ivory and other Arctic luxury goods.

The image of a peaceful Inuit is also under challenge:

The emergence of hierarchical village societies, containing over-classes of artists and political leaders, and supported by slaves, is linked to their learning to hunt for the largest mammal in their environment, the bowhead whale. Intense competition for hunting grounds, over-population, and the ability to maintain permanent militias were factors in the emergence of violent conflict. Archaeologists have uncovered fortified Bering Strait villages, and the Thule were known to wear Chinese-style slat armour and use the Mongol recurved bow.

Conflict in the region was not just an event a thousand years ago it has been regionally common, even back to 13,000 BP. No wonder the Vikings had such a hard time in Western Greenland, and chose to leave L’Anse aux Meadows to its resident tribes. (But it might also explain where all those polar bear skins came from, that ended up going to the Vatican from the Greenland diocese.) (THE LOST WESTERN SETTLEMENT OF GREENLAND, 1342, An M.A. Thesis in History, by Carol S. Francis, California State University – Sacramento – Fall 2011).

Well this was more of a digression than I had intended when I started writing this post this morning, but rather it serves to illustrate, through the drastic loss of life when European and American cultures first met, and through the lack of much archaeological evidence until recently, the difficulties in generating a highly detailed history of events over the past 20,000 years.

I plan on writing about the Red Paint People next, and their arrival, and then we might get to the dissertation, cited above, and the discussion topics that it falls into regarding the interactions of Europeans and Native Americans in the MWP.

Sea-levels and Permafrost burials

The calamities that are predicted by those arguing for the need for carbon dioxide emission controls typically focus on the rapid rise in sea levels that are predicted as the temperature continues to rise. The rise in temperature is also anticipated to get more rapid, since, as the tundra that covers much of the countryside along the Arctic Circle warms, it is expected to emit more methane. There are a number of other commentators who are talking about this (and which I will refer to in Saturday Pick Points later today) but I thought I’d dwell just a little more on the Medieval Warming Period Experience to counter the latter. But first a comment on the “rising tides” that are cited as the greatest concern. (They were after all the basis for the court decision that the EPA had to regulate carbon dioxide.)

On April 2, 2007 the Supreme Court released its ruling in the case of the state of Massachusetts vs. the Environmental Protection Agency. Massachusetts and eleven other states, along with several local governments and non-governmental organizations (petitioners), sued the EPA for not regulating the emissions of four greenhouse gases, including carbon dioxide (CO2), from the transportation sector. The petitioners claimed that human-influenced global climate change was causing adverse effects, such as sea-level rise, to the state of Massachusetts. In a 5-4 decision, the court ruled in favor of Massachusetts et al, finding that EPA has the authority to regulate CO2 and other greenhouse gases.

If one goes to the National Institute of Oceanography, in India, one gets this curve for the last sea-level at Mumbai for the past 135 years, and it suggests that there is nothing particularly remarkable about the current changes in sea level, nor is there any discernable effect due to GHG Global Warming.


Sea-level variability at Mumbai, which has the only more-than-century-long sea-level record in the Indian Ocean. Annual sea level (cm) is plotted as a function of time to reveal the variability of the annual sea level over the length of the data record (1878 to 1988 in this figure) (red), showing the inter-annual variability in sea level at Mumbai. Filtering annual sea level with a 10-year boxcar filter (10-year running mean) (blue) reveals inter-decadal variations. At Mumbai, these inter-decadal variations are as large as are the variations from year to year.

The University of Colorado at Boulder has a site that lists, from Tide Gauge Records, the rise in the oceans over the decades, and the site includes this table:

Source University of Colorado Boulder.
With today’s technology it is now possible to see these changes in a more global sense. JPL, for example, has an animation site of seal-levels (the sea-level viewer) which is worth a visit. as well as the patterns shown by major currents.

However if one looks at the satellite measurement of sea levels, one gets:
Source Univ Colorado Boulder

What is interesting is to note that this data comes from two different satellites, and that if one separates the two (Jason and Topex) one gets a slope for the TOPEX of 3.22 mm/yr, but for the Jason data the slope is only 2.4 mm per year, which is more in line with the tide gauge data, but which also suggests that the sea-level rise is slowing down, rather than speeding up. (The average for the two together, I compute to 3.28 mm, but that is rounding).

Now the second point required that I adopt a new bit of technology. The book that I have started to quote more and more from in regard to glaciers, ice sheets etc is Jean Grove’s Little Ice Age of which I have written before. However, as I also noted, the original costs $320, and if you want the new edition it is $850 on Amazon. Much as I find this fascinating, this is a bit steep, and so I borrowed the books from the library. But they had to go back – and hence the step to new technology. I discovered that the book costs $11 on Kindle. Egad! I pay for the machine with one purchase.

I’m still learning how to use the machine, and so it will take a couple of days before I can pull quotes and pictures properly from it to insert here. But here is the relevant section, copied out, that I wanted to point to today. We know from the recent excavations at Sandet in Greenland, that the ground is now permafrost to the surface. However, to quote a little from Grove

It is known that Herjolfsnes remained inhabited until after 1480, though it is clear that the climate had deteriorated by 1350. This is shown by the fact that costumes from burials were penetrated by tree roots until those of the 1350’s and subsequent decades, which remained in remarkable state of preservation, indicating that not long after burials of this time the ground a meter or two deep had become frozen throughout the year (Norlund 1924, Howgard 1925, Gad 1970).

So all the current permafrost in that latitude was not frozen prior to 1350. Thus it was giving off the decomposition products prior to freezing. The farm at Sandet still smells like a midden when its soil is thawed. Ergo if there was no vast global melt-down at the time, and history would surely have recorded one, when these latitudes were not frozen, then there won't be this time. And the Medieval Warming period ran from about 930 to 1350, so I would suggest that we relax and stop all the hysteria.


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Advancing and Retreating Glaciers in the Holocene

I was musing as to how to start this post, and so I Googled “Medieval Warming Period”, and found that there is a post at Gristmill about talking to an AGW sceptic, that states

There is no good evidence that the MWP was a globally warm period comparable to today. Regionally, there may have been places that exhibited notable warmth -- Europe, for example -- but all global proxy reconstructions agree it is warmer now, and the temperature is rising faster now, than at any time in the last one or even two thousand years.

This is actually a set of incorrect statements. And it epitomizes one of the problems facing those of us that would prefer to have this as a scientific debate about the facts. The problem is the blanket refusal of those who consider that greenhouse gases are the cause of global warming to recognize the considerable body of scientific evidence that contradicts their case.

I am going to be quoting from Jean Grove’s “Little Ice Ages – Ancient and Modern” again in this post, but from volume 2 this time. As with the first volume the book is copiously referenced with detailed scientific studies, the Bibliography runs 70 pages of 2-columns, with about 16 references/column/page, which works out to over 2,000 references on the subject. The subject is as the title says it is, the ice ages of the past millennia, with evidence of their extent and intensity, and their global nature. Between the periods of increased cold, there are periods where it is warmer, even than today. These also are documented, with evidence. The evidence is debated, and weighed as to credibility. It does not require a proxy to show that where a farm existed and there is now ice, that it was warmer when the farm was there than it is now, as an example, or when the advance of a glacier sheared off the trees, to surmise that it was getting colder.

The scope of the work, and recognize that this is a summation of the work of the hundreds of scientists writing the papers that she has combined and integrated, covers largely the advance and retreat of glaciers. In the first volume, which I covered earlier, the main focus was on looking at the last Little Ice Age, and its global impact with glaciers from Alaska to New Zealand growing to new lengths, and then in the early 1800’s starting to contract.

In the second volume the emphasis switches to the Holocene as a whole, namely roughly the past 10,000 years. And, while glacier advance and retreat cannot by itself be taken as a sole indicator of global temperature, some of the concurrent events (the rise and fall of the tree line in the region surrounding the glaciers, and the formation of lakes or peat bogs where glaciers stood, for example) serve as proxy thermometers. As an example, writing about the Engebreen and the main Svartisen glacier

A warm period about 1500 BP (before present) (cal AD 500) is recorded by the growth of pine forest above the present pine limit. Then came ice advances marked by sheared off trees in the period AD 360 -900 (Worsley & Alexander 1975). Although the exact years in which these trees were killed has not been identified by comparing their ring sequences with the long dendrochronological series now available, their radiocarbon dates can be taken as more precise than those derived from soil and peat samples. They demonstrate that Engabreen advanced and retreated several times in this period to form a complex moraine. Karlen (1991) pointed out that the tree ring sequence indicates several temperature fluctuations with cold summers around 550 AD, and again between 780 and 970 AD, though with 20-30 years of summer warmth around AD 930.

In such a manner and going from country to country is the evidence amassed. Karlen, for example, shows that the altitude of pine forests were 100 m above the current limit in the Medieval Warming Period around 1,000 years ago, and that the height of the tree line had varied up and down over 200 m in the Holocene. He concluded that this represented a change of about 1.5 degC.

I have used Greenland as an example of historic climate change in the past, and it is interesting to quote

By about 6,000 calBP the inland ice margin had retreated to a position close to the present (Weidick et al 1990) . . . .Retreat of the ice continued and from at least 4700 to 2700 calPB the inland ice margin was inland of its present position by as much as 15 km. The scale of the retreat is indicated b subfossil shells, reindeer bones and a walrus tusk, brought to the surface by the ice of Jakobshavn Isbrae and deposited in moraines. The reindeer bones which have been dated to 3040 +/- 60 BP must have come from above the snow line over 50 km from the ice margin, and moved westwards in the ice at a rate of about 20 -50 m per year.

The mean annual temperature at Jakobshavn on Disco Bay in the Holocene Climatic otimum is estimated have been about -1 degC, as opposed to -3 degC currently. The great fjord stretching 60 km to the east where the tongue of Jakobshavn Isbrae is now more than 700 m thick, was then free of ice. With readvances probably around 2500 and 1200 BP the ice haltingly returned. Finally, between 1850 and 1880, the Little Ice Age advance culminated, since when the ice has continuously thinned (Weidick 1996).

The front recession has been plotted over the past 150 years, and is shown here.
Retreat of the Jakobshavn glacier

The book continues, going from ice field to ice field as it moves from the Arctic to the Antarctic. Then it plots a curve showing the coincidence of the periods of glacial advance around the world, over the Holocene. Obviously in some parts the work has yet to be done to fully define the periods and details of the glacier movements. Yet the one thing that stands out is that over the past 3,000 years there has been a remarkable consistency in the periods, around the world, when glaciers advanced, and when in the presence of a warming period they retreated.
Regional summaries of glacier expansion (Grove Fig. 15.25)

The book notes the existence of the Dansgaard-Oeschger cycles

The Dansgaard-Oeschger cycles turn out to he bundled into longer cooling cylces, each of which ends with an abrupt shift from cold to warm temperatures. These bundles are known as Bond cycles. It appears that during the abrupt cold-to-warm shifts at the end of Bond cycles temperatures must have changed by several degrees within a matter of decades, both at the ocean surface, and in the atmosphere over Greenland.

Though not understood, the book suggests that the climate change may have been induced by changes in atmospheric dust.

Well, as you can see, the real story is quite different to that which Gristmill would have you believe. Sadly at present there are just not that many folk that will question the statements that they blandly make. I will add the correlative plot from the book in the morning (or rather later in the morning).
Addenda The graphic is added above - fig 15.25.

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From the Little Ice Age to today -rates of climate change

Much of the media coverage of the changing climate relates to the changes in glacier size, and their relative retreat over the past four decades. In the last Saturday post, I quoted the overwhelming scientific evidence for the presence of a global Little Ice Age (LIA) as documented by Jean Grove.

What I would now like to do is show, through the work of Syun-Ichi Akosafu, of the International Arctic Research Center, that the transition from the LIA to today began long before the considerations of Global Warming and carbon dioxide forcings were much thought of, and, with the backing of the solid science that has documented these changes, that these changes have very little sensitivity to the purported effects of increased carbon dioxide levels. Further I would underline his comment that it is not possible to study climate change without long-term data – considering long term to be not 60 years or even 600, but rather the periodicity of climate changes over the last 3000 years. And that requires archaeological information as well as that of proxies alone, particularly as it relates to those that live in the Arctic regions.


In beginning let me note that as the global temperature, over the last decade, has refused to follow the predicted path of those who espouse global warming, so the period over which average temperatures are defined to denote the trend in climate has been extended, from three, to five, to ten, to the latest fifteen year averages. Let us, for the sake of scientific honesty, decide that five years is a reasonable period over which to define a mean, and then move into the discussion.

Akosafu begins by showing that, if we plot this 5-year mean over the past 140 years, then the trend can be divided into a steadily increasing part (the black line) with, superimposed upon it variations that he calls natural, but that will be examined and discussed as we work through the paper.


Figure 1. Global temperature change, shown as a 5-year average and defined by the overall trend, and the variations thereon. (Akosafu Fig 1e).

Given the whole debate about global warming and carbon dioxide levels, it is appropriate to also include his figure 2, which shows the change in both over the last 150 odd years,
Figure 2. Global temperature (5-year smoothing) plotted with CO2 levels

By comparing temperature records from Vardo, in Norway, with the ice core data from Severnaya Zemlya, he shows that the two can be correlated, and then uses the ice core data to show that the temperature it records has been rising since about 1780. This is then correlated with data from coral studies on the island of Guam that similarly show a temperature rise, which started around 1800. The paper ties this date to changes in the time that ice freezes over lakes and rivers, and when it melts. The conclusion is visibly evident that there has been a change, and that it dates back to around 1800.

However much of the response to mention of both an MWP and an LIA has suggested that the events were localized to Western Europe. Now Grove showed through quotations from numerous papers that this was not true, and Akosafu equally strongly refutes that argument with data from both Peru and China,
Figure 3. Oxygen isotope values translated into temperature variations for both China and Peru over the past 400 years (Akosafu Fig 4c)

While many folk seem to prefer to rely purely on the scientific numbers derived from proxy values, I feel that information from contemporary historical documents can be equally or more valid. Thus the reports of cooler summers between 1550 and 1750, which led to deaths because of the poor harvests, and thus famine, provide information that should not be ignored.

The generality of that condition, and the global evidence of a change to a warming trend after about 1800 is well documented. It is this evidence, and the timing of the start of global warming, that shows that it is a natural, rather than an anthropomorphic change. Anecdotal information, such as the fact that Permafrost formed during the LIA around Fairbanks is only now starting to thaw, does not define the depths of the cold that many places saw and he points out (Figure 6a) that for those many places around the globe, the average temperature in the 1700s was considerably below that modeled by Mann et al, in their famous “hockey stick” paper that formed such a central theme to the IPCC report of 2001. In fact he quotes a table from the NRC 2006 report on global temperatures that confirms, with half-a-dozen plots, that temperature started rising somewhere around 1800. He rightly asks the question that, if CO2 levels did not start rising significantly until 1946, what was the cause of the earlier rise?

If, in fact, one examines the trend of temperature rise from 1800 to 1900 and then from 1900 to 2000 and subtracts the rate of change in existence before carbon dioxide effects are postulated to have occurred, then one finds the pre-existing rate to have been 0.5 degC/100 years following 1800. With the IPCC claim of a temperature rise of 0.6 degC/100 years, then the difference due to CO2 initially appears to be 0.1degC/100 years.

Now if the drop in temperature during the LIA was a total of 1.5degC, such a rate would bring us “back” to date only 1degC. And there are records that suggest that the MWP was, in fact, warmer than today’s temperatures. This, however, only deals with the “black line” portion of Figure 1. Akasofu now looks at the variations around that trend, namely what is referred to as the “multi-decadal oscillation.” This can be seen, in Figure 1, to be an oscillation, but to those anxious to prove Global Warming, it is this oscillation above the underlying trend, coincident with the rise in CO2 levels, that is the marker to our future doom.

However, as an initial point, it should be noted that the nature of oscillations is that, after swinging one way in periodic mode, they then start to swing back. And the phase of the oscillation, as seen from Figure 1, is such as to suggest that the return should begin around 2000 – as it did. This variation is around 0.15degC /10 years, and cycles, as shown, around the mean growth.

Studying the changes that this warming is inducing, Akasofu looks in more detail at the actual specificity of occurrences, rather than the generality. Consider, for example, the reduction in the Arctic ice cap. This is not a uniform contraction, which one might anticipate if the cause were a universal warming, but rather is maximized along the Siberian coast, where the currents from the North Atlantic – under the driving force of the North Atlantic Oscillation (NAO)- have accelerated the melt. The characteristics of that melt – the ice is melting from the bottom, rather than the top, confim that it is a water current related phenomenon, rather than a surface temperature caused result.

In earlier posts I have commented on the retreat of the glacier at Glacier Bay in Alaska, and will take the opportunity of pasting his illustration of this, so that I can refer back to it later. You will note that it shows the glacier retreating to its greatest extent, before 1860.
Figure 4. Glacial retreat at Glacier Park

Similar plots are presented for the Franz Josef Glacier in New Zealand, and the Gangotri Glacier in the Himalayas, as well as the advance and retreat of the glaciers in the west-central Alps.

As I pointed out, when discussing Bangladesh, Akasofu also does an evaluation of the rise in sea levels over the last hundred years, and notes that while the average has been some 1.7 mm/year in recent years, rather than increasing, as one would expect with the glaciers melting, and the ocean warming, in fact the rate has dropped below 1.4 mm/year.

Hidden now, in the heart of the paper, lies some of the more damaging evidence against the modeling of Climate Change that is presumed by so many to be accurately predicting our future.

In the post that induced my departure from The Oil Drum, and as Akasofu confirms, Greenland, as a whole has not been warming in the same mode as the majority of the Arctic regions. When, however, the IPCC Arctic group were asked to run their models to hindcast the behavior of the Arctic regions over the past fifty years, the IPCC models were nowhere near accurate in their predictions of what actually occurred.
Figure 5. IPCC prediction vs reality (on the left)

Further, because the IPCC only focuses on the period following 1975 they neglect the changes in the Greenland ice sheet that occurred during the 1920-1940 period which were substantially greater in magnitude than those now occurring, but which could not have been caused by GHG. And, this after all being an Arctic Research Center, they also point out, contrary to MSM reports that the actual temperature of the permafrost has stopped rising, and in fact the methane levels “off-gassed” have decreased, since about 2000.

I will forego discussion of what might cause the larger cyclic variation (the MWP – LIA cycle) to another time.

So there you have it, to those willing to do "due diligence" on the changes in climate over the past two centuries, the evidence is substantial that the fears so assiduously heightened in the media, are not, in fact, based on fact. We'll get into the MWP and earlier parts of the cycle, in future posts.

Glaciers and the Little Ice Age

I suppose that many of us that are trying to do “due diligence” in looking at the scientific data that relates to the issues of climate change come to the table with different perspectives. In my case, as I explained earlier, my curiosity was wetted by the information that the Earth goes through cyclic periods of warming and cooling, the most recent of which have become known as The Medieval Warming Period, and the Little Ice Age. I am currently reading Jean Grove’s “Little Ice Ages-Ancient and Modern.” She was a Fellow and Director of Studies in Geography at Girton College, Cambridge, and, since her death in 2000, the book has been issued in a second updated edition, by Dick Grove, her husband. It is now in two volumes, and this will be about some of the information that lies in the first of these. It deals with glaciers, but glaciers grow from snow, and that snowfall has changed over the years.


As a fairly comprehensive text, it takes the history of many of the glaciers around the world back beyond their most recent past to discuss how they have advanced and retreated. Using evidence from, among other things, church records, it shows how farms that were prosperous in the MWP had been wiped out and over-run by the glacial advances of the LIA. And it shows, through copious references to the scientific literature in the field, the times and rates of these advances and retreats. Some of those who discuss this cycle have suggested that the MWP was a localized event in Europe, this text clearly shows that it was not, though I will talk about the MWP period more in a later post, and in this one concentrate on the event that is the most recent Bond event, as some now call these cyclic cold periods. It is interesting that in the fluctuating entry that covers the Bond event at Wikipedia the LIA comes and goes as a recognized Bond event (today it is gone).

Jared Diamond, in “Collapse – How Societies Decide to Collapse of Succeed,” wrote of the contrast between the native population of Greenland (I will call them the Thule, though there are debates on which group it was) and those descended from the families who came to Greenland with Erik the Red in around 982 AD. (He does not address that the Thule may, in turn have arrived in Greenland from Alaska by migrating across the North of Canada in the same time frame). Diamond concludes that the inability of the Vikings to adapt to the sea harvest as the weather got colder made it more difficult to sustain the conventional farming life in Greenland. However Grove points out that the advance of the glaciers to the sea changed the patterns of fish migration, so that the harvest may not have been there, at least in the form that they were used to – though if the fish were not there, then presumably the seals that feed on them would also have migrated, and the Thule also, so that only the farmers, tied to the land would be left starving). However Grove also quotes Arneborg who examined the bone collagen of some of the settlers, which indicated that the Norse diet changed from 20% sea food in the eleventh century to 80% in the fourteenth, so perhaps it was just the climate change that marked the beginning of the LIA in that time frame that was the real cause of the disappearance of the Norse.

Being tied to the land in the peculiarities of society of the time had considerable disadvantage as the glaciers advanced. The cold winds around the glacier were not good for crops. Grove quotes from a court of inquiry report of 1742

It was apparent that it was the nearness of the glacier which is the cause of crop failure on this farm, for in the fields where the crops were now in ear, the ears on the side towards the glacier from the west were quite brown, and on the other side green, though some ears were not even in bud because the cold and the strong cold winds which the glacier exhales freezes it away in one night’s still weather.

With the winter snowfalls and short cold summers the glaciers, in this case the Bersetbreen branch of the Jostedalsbreen glacier in Norway, advanced through arable farmed land over the period from 1680 to 1745. After reaching a peak advance in 1748 it has since retreated some 4.5 km according to Erikstad.

And it is in this advance and retreat of the glaciers, whether in Greenland, Norway, Switzerland The Pyrenees, the Urals, The Caucasus, Tibet and the Himalaya, Mexico, Ecuador, Africa or South America that the bulk of the text is devoted. The dates of glacial advance, the point of maximum range and then the consequent retreats are documented and discussed. The book goes into considerable detail, where it is available, documenting both glacier behavior, and the effects that the extensions of the glacier had on the surrounding inhabited areas. This effect was particularly severe in Europe coinciding as it did, with the onset of the Black Death. And while glaciers grow and shrink in part due to changes in precipitation, she documents, for example, the changes in Snowfall in Scotland during the LIA, as illustrative of the changing patterns that predominated.

Grove cites others who show that the LIA was pervasive outside of just the glacial fields. For example Thompson, who considered that 1490 marked in the beginning of the LIA in the Northern Andes, with the long-term Holocene cooling culminating in the seventeenth and eighteenth centuries.

In Chile the Ada Glacier advanced until some time after 1858, but by 1882 was in retreat, and has been retreating since. Similarly in Argentina by 1895 Hauthol was reporting on the glacier in the Atuel valley wrote that

the glaciers clearly indicate not only that until a short time ago they were of much greater extent but also that they are now losing volume and retreating at a great rate.

Between 1914 and 1937 Groeber reported that the glacier had retreated 3.2 km.

The Patagonian Icefields include the San Rafael and San Quentin glaciers which have been studied more intensely than others. Both have been in general retreat for most of the last century, after reaching a maximum LIA extent in around 1876. The San Rafael has oscillated over a distance of 10 km. Since the glaciers have had floating tongues which is more prone to precipitation as a means of control, rather than temperature, these oscillations may not be climate controlled. Moving further south into the Southern Patagonian Icefield

In the early part of the twentieth century the easter outlet glaciers of the Southern Patagonian Icefield retreated rapidly from extended postions reached in the mid to late nineteenth century, leaving clear trim lines in the vegetation (Lliboutry, Clapperton).

A short review of a book that has references to supporting scientific papers in virtually every paragraph and which covers the field with the depth and detail that this does can do very little justice to it. The book, however, clearly shows that the LIA was a global event, and that it brought glaciers forward around the world. Further it shows that the globe began recovering from the depths of the LIA in the 1800’s and glaciers have been retreating from their maximum extent for most of the twentieth century. This predates the increases in carbon dioxide so that glacial retreat, in and of itself, cannot be used as evidence of CO2 impact on climate. The variations that occur in advance and retreat speeds and directions, even between glaciers that are quite close show that there can be over-riding other parameters that are more influential than temperature change, although when there is a general trend for glaciers to grow through the LIA from minimal positions before it, and then to retreat similarly generally after the peak of the LIA conforms to its presence.

Other evidence can be used to surmise the temperatures before the LIA arrived, Grove cites grain being grown in Greenland and Iceland, in areas where farms have not yet been able to be re-established. She cites orange growth in the Tang and Deng counties of Xichuan (which cannot grow them at present) as late as1264 to mark the beginning of the LIA, with the MWP ending somewhat later in Tibet, though there is some discrepancy in the data from different ice cores from that country.

On an editorial note I would have added the references cited, unfortunately they are in the second volume, and I don’t have that one yet.