Grantville Gazette 37

Subtropical North Atlantic: there's a broad shallow low centered on 1700, and a high in the early- and mid- 16^th century.

Western Greenland: The entire LIA was warmer than in the late- 14^th century, but at its warmest in the early-15^th and coldest in the late- 17^th and late-19^th centuries.

Central England: The LIA saw a long decline to the low of late-17^th century, then an improvement in the early-18^th century. Temperatures remained well below the broad peak of the 13^th century.

Fennoscandia: the deep low is just after 1600, and temperatures gradually recovered to a broad peak in the late-18^th and the whole 19^th centuries.

Eastern China: the biggest temperature drop of 1000-2000 was before the LIA, in the 12^th century. During the LIA, temperatures remained at or above their 14^th century levels, with a broad peak in the 19^th century.

Tropical Andes: the LIA really began around 1500 here, but there were no sharp lows. The lowest points are in the late-17^th and late-18^th centuries. The early-17^th century was cooler than the 15^th century but otherwise unremarkable.

Thus, the LIA was not simply a four-century cool period; it included warmer and cooler intervals, and these weren't synchronous between regions. However, it has been contended with some justice that it was a period of greater temperature variability.

1630s Europe: Historical Accounts

We can learn a lot about past climates from historical records. At the very least, they speak directly to the real-life consequences of weather conditions (droughts, floods, freezes, heat waves, and storms). And in some cases the historical records provide quantifiable information (e.g., the dates that particular lakes or rivers froze or thawed, the dates of harvesting grapes or other crops) that can be correlated with overlapping instrumental records so that the older temperatures may be inferred.

While our interest is particularly in the 1630s, we will from time to time look back at dates that would have been in living memory, and forward to the 1640s.

Pfister has constructed, by rating the severity of temperature and rainfall extremes in documentary accounts and weighting them together, an index of climate impact on European agriculture. There were major peaks in 1569 -73, the late 1590s, 1614, and 1626-29. 1628 was a 'year without a summer.' (cp. Battaglia). 'After 1630 the level of climatic stress drops substantially.' The next peak, in the 1640s, was of about half the magnitude of the one in 1626-29.

Temperature increased from the 1620s to the OTL 1630s, and the number of witchcraft trials in eleven regions of Europe, standardized relative to the regional means, declined. In the OTL 1640s, they increased again, to higher than the 1620s level (Oster, Fig. 1).

Great Britain. According to Wikipedia/River Thames Frost Fairs, in the 17^th century, the Thames froze over at London in 1608, 1621, 1635, 1663, 1666, 1677, 1684 and 1695. With particular regard to the winter of 1635, the frost was severe from December 15 to February 11. It was followed by a warm and moist spring, and a very hot and dry summer and autumn. But the following winter (1635- 36) was unseasonably warm. 1637 was also cold. The summers of 1636, 1637 and 1638 were all hot and dry (Marusek 116; LambCPFF 568).

During the LIA, the 25-year average of the English price of wheat increased from its low around 1500 to a high around 1650, then dropped to a shallower low in the late-18^th century, and then climbed to a greater high in the early-19^th century (Flohn 44; LambCPPF 462).

Note that during the coldest parts of the LIA (which for England was the late-17^th century), the growing season was shortened by 1-2 months compared to that of modern England (Mandia).

Scandinavia and the Baltic. Historical climatologists have found records of the date of ice break-up at the harbor of Riga (Latvia) going back to 1529. We know that in the 1620s, 1620-21 was a severe winter, 1622-23 was average, and 1625-6 was mild. And in the 1640s, 1642-3 was severe, 1648-9 was average, and 1649-50 was mild. But the data for the 1630s are missing. The average break-up date is March 24 in a mild winter, April 3 in an average one, and April 12 in a severe one, but the variability is fairly high. (Jevrejeva). For the 17^th century, the earliest date was Feb. 2, 1652 and the latest May 2, 1659 (LambCPFF 587).

There is also data, complete from 1600 on, for ice-breakup at Tallinn (Estonia), which is near the average western limit of the ice cover in the Gulf of Finland. (Tarand 192). The means for 1597-1629 were year-day 97.4 for Riga and 106.18 for Talinn, and for 1630-1662, they were 80.25 and 99.73 respectively. The estimated winter air temperatures for Tallinn were -5.84^oC and -4.72^oC for the two periods. And the 'Ice Winter Severity Index' for the Western Baltic dropped from 0.73 to 0.44 (it was 0.02 in 1988-93). (Eriksson; Tarand 192).

Alas, the post-1622 Great Sea Toll records for Stockholm, recording the dates of first arrival and last departure for each shipping season, were requisitioned by the Swedish Army as-brace yourself-wadding for artillery. Nonetheless, useful records relative to the shipping industry have survived, and the climate observations from these records have been scaled and calibrated with overlapping instrumental data to reconstruct winter temperatures for Stockholm. These reveal that 1614-23 (-2.43^oC) and 1624-33 (-2.20^oC) were the second and fourth coldest decades since 1500. (The dangers of relying too much on the generic Little Ice Age label are shown by the fact that one of the five warmest decades, 1734-43, is within the conventional LIA.) The decade of 1634-43 was a bit warmer than 1624-33.

I have found reports of crop failures in Norway in 1632 and 1634 (GroveLIAAM, 67). These are probably attributable to the proximity of glaciers. The 1742 report of the court of inquiry on Elekrok stated 'it was apparent to us that it was the nearness of the glacier which is the cause of crop failure on this farm . . . the ears on the side towards the glacier . . . were quite brown, and the other side green. . . .' (71).

The Netherlands. In East Friesland, on Sept. 1, 1637, there were great floods (Marusek 116). (The specific date won't be repeated in the new time line, but there may still be a propensity to flooding that autumn.)

For wheat prices, the first LIA climb came later than for England, possibly in the 1640s. Otherwise, the fluctuations were similar to those for England but smaller.

Germany. The walls of historic buildings at Tonning on the west coast of Schleswig-Holstein reveal that the flood of Oct. 11, 1634 reached a height of four feet above the ground surface. (LambCHMW 17). On Norstrand Island, 6,123 people drowned, and 50,000 livestock were lost (Rabeljee). This flood is mentioned in Grantville literature, but the up-timers didn't think to warn King Christian about it because they assumed it would be 'butterflied away.' Instead, it came ahead of schedule. See Boyes, 'A Great Drowning of Men,' Grantville Gazette 28.

The price of rye in Germany over four centuries has been analyzed. Peaks corresponded to a poor harvest-this could be because of climate, or because of warfare. Considering just 1590-1650, there were small peaks in 1590 and 1610, moderate ones in 1626, 1634 and 1649, and a large one in 1622. However, the worst one of all was that of 1816 (the 'year without a summer') (Mandia, Fig. 17). Other than in 1634, the 1630s appear to have offered cheap rye-albeit not as cheap as in the 'good years' of the 16^th century. The high prices in 1634 were probably attributable to plague (Pfister2007, Fig. 8).

France. On October 6, 1632, southern France was so cold that sixteen of Louis XIII's bodyguards died from exposure (Marusek 115). The winter of 1638 was also severe; in Marseilles, the 'water froze around the ships.'(116).

Wine grapes will reach maturity more quickly if the growing season (April-September) is warm, than if it is cool. Based on the extensive wine harvest data, the summers of 1634-39 were warmer than the 1599-1791 mean (Ladurier; Chuine).

French wheat prices followed a pattern similar to that of British, but the fluctuations were more moderate (Flohn 44).

Switzerland. Based on historical documentary evidence, Pfister constructed crude thermal (warm months-cold months) and wetness (wet months-dry months) indexes for Switzerland. The 1630s appear to be a little on the warm side, and markedly on the dry side. The 1640s were colder, although nowhere near as cold as the 1670s, 1690s, or 1810s, and not as dry (LambCHMW 204).