An explosive volcanic eruption, a bishop’s ring and the Little Ice Age: How freezing weather and near famine arrived in Scotland in 1674…
Or, four events that form an interesting historical pattern, but may not be linked one to an other. Then again, what if they are?
The Eruption of Gamkonora in 1673.
1. The Volcano
On 20 May, 1673, Mount Gamkonora, a volcano in Indonesia, violently erupted obliterating the top of the mountain and blasting ash far into the stratosphere. In the tsunami that followed villagers were killed. The impacts of the eruption were not just local, it also impacted on the global climate. Perhaps surprisingly, it may have had an effect on the other side of the world, in Scotland.
Today, the 1673 Gamkonora event has been eclipsed in historical memory by other, colossal, eruptions in the area whose names resonate down through history, Tambora in 1815 and Krakatoa in 1883. How large the 1673 eruption was is not clear. It was probably similar in scale to the better known VEI 5 eruptions of Vesuvius in 79 AD and Mount St. Helens in 1980, but probably a bit smaller that the VEI 6 eruption of Mount Pinatubo in 1991.
What does a forgotten Indonesian eruption have to do with Scotland? It is certain that nobody in Scotland in 1673 knew about what took place at Gamkonora. Although the volcano lay near to Ternate, one of the legendary Spice Islands of world history where the Dutch were present, a very long sea voyage lay between the event and news of it reaching Europe. What may have taken less time was the first tangible sign of it to appear over Scotland.
2. A Circle Round the Sun in Summer. 1673.
On the 6 August, 1673, the Reverend Robert Law observed something unusual in the sky:
‘This summer, 1673, was a very rainie summer, and the harvest exceeding rainie and dangerous. On the 6th of August was observed a circle about the sun, much lyke to a rainbow, about 12 hours in the day; the lyke has not been usuall, which, as it seems, portended much raine by the event of it; and in October was there a windie Thursday through Britain and Ireland, that shoke more corn upon the ground than what stood. (Law, Memorialls, 52.)
What had Law observed? From his description it appears that he believed that he had witnessed either a halo around the Sun, a relatively common event that is caused by ice crystals semi-randomly orientated in the atmosphere, or a corona, which is caused by water droplets. Law specifically said that it was a portent of ‘much raine’.
However, did Law know what it was that he recorded? He also states that ‘the lyke has not been usuall’ and that it was ‘a circle about the sun, much lyke to a rainbow’. Law certainly knew about rainbow-like optical effects around the Sun, as he identified a sun dog over Glasgow in 1683.
Halos and corona are not the only optical phenomena that produces a circle round the Sun. Over two hundred years after Law witnessed the circle that was ‘much lyke to a rainbow’, the Krakatoa eruption led to the recognition of a different optical phenomena, a Bishop’s Ring.
It is here that Law’s description is of particular interest. What Law observed was ‘a circle about the sun’ which was ‘much lyke to a rainbow’, but not, apparently, the same as a rainbow. A Bishop’s Ring around the Sun has an inner rim that is whitish or bluish white and an outer rim which is reddish, brownish or purple. It is ‘much lyke to a rainbow’, but is not a rainbow. It is produced after large, explosive, volcanic eruptions throw sulphur aerosols high into the atmosphere that then move around the globe. For those who doubt that an Indonesian volcano can cause a Bishop’s Ring over Europe, here is an image of one over Finland in March, 1992, that was caused by the eruption of Mount Pinatubo in the Philippines in June, 1991.
A Bishop’s Ring from Pinatubo © Marko Riikonen.
If Law recorded a Bishop’s Ring, it was probably first observed over Glasgow or Dunbartonshire, which was where Law lived, 78 days after the Gamkonora eruption. Intriguingly, there is a parallel with the discovery of the Bishop’s Ring after Krakatoa in 1883. After the cataclysmic eruption of the volcano on 27 August, a ‘constant halo observer’ noted it over Sunderland on 27 November, i.e., 92 days later. It is clear that atmospheric circulation, local weather conditions and a keen eye for such phenomena are an important factor in the observation of such an event, perhaps today few more people would both pay attention to it and record it. Law certainly was interested in providential signs in natural phenomena. Although he specifically states that the summer was ‘very rainie’, it appears that 6 August was a clear, sunny day suited to observation as the entire circle was observed in the sky at ‘about’ noon.
In the end, it is not clear which form of optical phenomena that was ‘much lyke to a rainbow’ that Law recorded in the sky over Scotland, but he may, perhaps, have recorded a Bishop’s Ring over two centuries before the optical effect was identified by science.
Whether Law recorded a Bishop’s Ring in 1673 is neither here, nor there, when it comes to the impact of the Gamkonora eruption on the global climate.
3. Volcanic Climate Forcing and the Little Ice Age
A recent scientific analysis of the ‘climate forcing of volcanic eruptions’ in the last 2,500 years which was published in Nature, Sigl, Winstrup, McConnell etc, ‘Timing and climate forcing of volcanic eruptions in the past 2500 years’, has indicated a stronger correlation between volcanic eruptions and sudden cooling in the climate.
At number three in the article’s ranked list of the sixteen largest post-volcanic cooling events of the last 2,500 years is the year 1675 with a temperature anomaly of -1.78̊C. Although 1675 was not one of the twenty coolest years on record, it was part of a decade between 1672/3 and 1681/2 that was, in global terms, the fourteenth largest average temperature anomaly (-0.77̊C) and eleventh in terms of an anomaly in tree growth found in the tree-ring data in the last 2,500 years. (See Extended Data Table 4 & 5 in article.)
The Gamkonora eruption was not one of the twenty largest eruptions of the last 2,500 years. Worse volcanic climate forcing had prevailed in the first decade of the seventeenth century that produced the largest temperature anomaly decade of the last 2.500 years (-1.17̊C) and contained the second highest single temperature anomaly (-1.82̊C). It was almost certainly caused by the eruption of Huaynaputina in the Andes. That event may have led to a great famine in Russia that killed over a million, but it appears to have had little effect on Scotland.
Gamkonora was not responsible on its own for cooling in the 1670s. The Little Ice Age, which caused cooling in Scotland, the rest of Europe and North America, was certainly a, if not the, major factor in the cold decade that followed Gamkonora. Volcanic activity is a possible cause of the Little Ice Age, but orbital cycles, changes in ocean circulation, the Maunder Minimum and decreases in the population have also been put forward as causes.
The weather in Scotland was, at times in the decade between 1672 and 1682, quite peculiar, or, at least, it drew the providential attentions of the Reverend Law and others.
Although the year 1675 has been described as the third largest post-volcanic cooling event in the last 2,500 years, the summer of 1675 was ‘very hott’ in Scotland and the end of the year ‘very warm’ until December. However, in September of that year, ‘a hurricane’ struck Scotland.
In the middle of the summer of ‘76, ‘a Great Haill’ stuck Dumbarton, while in December of that year, the ‘most violent frost’ that anyone could ever remember descended on the land.
However, it is at the very end of the fourteenth largest average temperature anomaly decade of the last two-and-a-half millennia, that a potentially significant sign of climate change appears in Scotland, when Inuit hunters were discovered in Orkney in 1682 and again in 1684. At the same time, the winter of 1682 was described as ‘rather like a spring for mildnes’, while the winter of 1683 to 1684 famously brought the Great Frost, which was followed by violent floods and strange portents.
The above illustrates how difficult it is to translate global climate cooling or volcanic climate forcing directly into local weather impacts, especially when we are reliant on sporadic and patchy historical sources for the decade.
What may be clearer is that the Gamkonora 1673 event had a significant impact on the Scottish climate in the year immediately following it, as it is generally a year or so after a large volcanic eruption that its impact on the climate is most tangible.
4. Gamkonora’a Possible Impact on Scotland
In early 1674, a vehement frost descended on the country that lasted for a biblical forty days. In the upland parishes of the South and the Highlands, families froze to death and cattle, sheep and wild animals died in great numbers.
The prolonged frost had knock-on effects. A terrible harvest ensued in the fall of 1674:
‘the harvest … being very evill for the corns that were so late in sowing the last spring, throw the long continuance of the frost, were not rypened for the most part, but very green in October, as if it had been in August.
The September of that year was very fair, and hott all throughout, and if Providence had not so ordered it, we would have had great scarcity of victuall, if not a great famine; but the October following was very rainie, which keept back the corns from rypening, and necessitat the people to take in the corn half wett and green, which occasioned much ill meall, though dear; for, till the beginning of October, there was little or no shearing; yet the following months, November, December, and January, there was not eight days frost, which helped well forward the labour and tillage of the land, and was very helpfull to the cattell, under that scarcity of fodder there was; and notwithstanding of all that great storm that was the last February and March, wherein many people and cattell dyed, yea, the deer and other wild beasts were starved to death with hunger and cold in the Hylands and other parts, yet was there not any tyme cows found fatter than in this last harvest [of 1674], and no scarcitie either of sheep or cows for slaughter, nor no dearth of them more than at other tymes. Thus the Lord who casts down with the one hand, lifts up with the other. Blessed be his name for ever!’ (Law, Memorialls, 73-4.)
‘This year, 1674, ends in a stormy winter; great winds in it, great scaith at sea, and great loss of ships. Victuall very dear; the boll of meall is 12 lib., and 20 merks for five furlots of malt, and that in January 1675, in the mercat of Glasgow;’ (Law, Memorialls, 73.)
Did the eruption of Gamkonora in 1673 lead to cold and erratic weather patterns in Scotland in 1674? Did the Reverend Law observe a Bishop’s Ring over Glasgow? It is an interesting pattern, but whether those events were connected is not proven.
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