Last week, while it was still officially winter, the temperature reached 87°F here in Michigan — for not one freaky day but for several days straight! What’s wrong with this picture? Well, normally our average high this time of year is about 45°F. The daffodils have already come and gone, all the trees are leafed out, the fruit trees are in bloom, and the Tulip Festival in Holland, MI is destined to be a glorious Stem Festival in early May. We won’t be free of the threat of frost or hard freezes until mid May. Farmers are anticipating millions of dollars in crop loss. If the baking temperatures hadn’t been so delightful for humans, the scene here would be downright apocalyptic! Never before has Michigan been so warm so early in the year. There were tornadoes near Ann Arbor and near San Antonio, Texas (a mile from my sister’s house) – places normally outside Tornado Alley. What the hell?
There is some evidence to suggest that folks living in Ireland during the mid sixth century might have been thinking exactly the same thing, although the climatic extreme at that time was the opposite – a global winter due to a possible comet impact. “In the period AD 536-545, Irish oaks, Sierra Nevada foxtail pines (Pinus balfouriana), and Fitzroya conifers (Fitzroya cupressoides) from Chile show years of extreme cold – the only years in which rings narrowed from severe weather match up across the three. There was no volcanic eruption to account for such global chilling, [but]…some astrophysicists have proposed a catastrophic encounter with cometary debris, an event recorded not only in tree rings but in Britain’s Arthurian myths and Celtic folktales” (Viney, 2003, p.68). Can anyone spot the references in these tales?
The Irish annals record no evidence that a comet was seen streaking across the sky during that time, but of course it might not have been visible from the Emerald Isle. There is one peculiar reference to “the failure of bread” in 538 AD (MacAirt & MacNoicaill, 1983, p. 73). Could this be a failure of grain crops? In 543 AD, the Annals of Clonmacnoise record, “Bread was very scarce this yeare” (Murphy, 1993, p.78). An eclipse of the sun “in the early morning 14 days before the calends of March” is noted in England in the year 538 (Ingram, 1993, p.22). It probably was a true eclipse, which can be verified, no doubt, by astronomical software, but it’s entertaining to think that it might have been some sort of debris cloud. According to Mitchell and Ryan, “There is some evidence to suggest that initially the climate in the later Iron Age was slightly warmer than at present. This will have meant that grain crops would have ripened better; in later times, it was necessary to dry corn [grain] in kilns before grinding it” (1997, p.248).
So, what are the climate trends in Ireland of late? “Frequent and violent winter storms and flooding from intense rainfall are the chief apprehension in Ireland as…more heat moves from the Equator to the poles. Between the 1970s and 1990s there was a fall in the number of moderate gales across the northern British Isles, while the number of damaging storms, with winds of between 60 and 80 miles per hour…approximately doubled. On the Irish west coast, gusts of around 100 miles per hour…have been experienced in several recent storms” (Viney, 2003, p.64).
Need any more evidence of global warming?
Ingram, J. (1993). The Saxon chronicle: AD 1 to AD 1154. London: Studio Editions.
MacAirt, S. & MacNiocaill, G. (eds.). (1983). The annals of Ulster (to A.D. 1131). Dublin: Dublin Institute for Advanced Studies.
Mitchell, F. & Ryan, M. (1997). Reading the Irish landscape. Dublin: TownHouse.