Grantville Gazette 37 gg-37

by Коллектив Авторов

  Generally speaking, cool season crops (oats, rye, wheat, barley) have a base of 0-5oC, an optimum of 25-31oC, and a ceiling of 31-37oC, and hot season crops (melons, sorghum) have a base of 15-18oC, an optimum of 31-37oC and a ceiling of 44-50oC (Change, Climate and Agriculture 75).

  Crop maturation is a cumulative process and crop scientists sometimes use the concept of growing degree days, awarding one GDD (oF or oC) for each degree (oF or oC) that the mean temperature on a particular day exceeds the base (some versions truncate if the temperature exceeds a ceiling). For example, wheat has a base of 40oF; corn, 50oF; and cotton, 60oF. Insects also have GDDs; 50oF for the European corn borer. (Fraise).

  A decline in mean summer temperature has a double whammy. It reduces both the height and breadth (growing season length) of the GDD curve. In England, in the coldest years of the LIA (1695, 1725, 1740, 1816), summer temperatures were about 2oC below the modern norm, and the growing season "was probably shortened by two months or even more." (LambCHMW 223).

  The principal Indian crop in New England was maize, and there's reason to believe that the native strains required 2000 growing degree-days (GDDs), base 50oF, to reach maturity. (The Indians also grew beans but these reached maturity more quickly.) In the 1960s, Connecticut, Rhode Island, Massachusetts, the Connecticut River Valley (NH-VT border), southeast New Hampshire and southwest Maine all were receiving at least 2000 GDDs (the area around Boston typically received over 2500 GDDs). A 2oF reduction in mean July and mean annual temperatures would put all of New Hampshire, Vermont and Maine, as well as northwest Massachusetts, under the 2000 GDD mark (Demeritt).

  Grantville is based on Mannington, located in Marion County, WV. According to the 1997 Census of Agriculture, Marion County had only one farm growing wheat and oats for grain. It had 251 farms producing hay (primarily from alfalfa). You can figure that alfalfa would be cut at 750 GDD, base 41oF, to yield a fiber content 40% neutral detergent fiber. For 45% NDF, you would allow another 220 GDD (Pennington).

  While there is no commercial production of corn in Mannington, canon says that there was a small quantity of seed corn available in Grantville as of the RoF (Weber, "In the Navy", Ring of Fire 1). There are also sunflower seeds, see Vance, "Second Chance Bird, Episode Two," Grantville Gazette 33. Sunflowers have a base of 44oF and require a GDD of something like 2300. (Putnam).

  We can compare these temperatures to those that are reconstructed for the places and times of interest.

  Bear in mind that temperatures below the base temperature might not just stop growth, they might kill the plant altogether. Flowers and young fruits of fruit trees are often killed by mild frosts (0-5oC) (Hatfield).

  The USDA defines plant hardiness zones based on the extreme cold (expressed as the average minimum annual temperature) that a particular plant can tolerate. Zone 1 is -60oF to -50oF, zone 2 -50 to -40, and so on up to zone 11, 40 to 50. Each zone may be further subdivided into two subzones, "a" and "b," with "a" as the colder half. (Zones 0 and 12 are special cases; 0a is under -65oF, 0b is -65 to -60, 12a is 50-55 and 12b is over 55.)

  Plants vary in terms of what kind of climate they like. For example, the orange tree (Citrus sinensis) is considered hardy in zones 9a-11a, whereas the Scots pine (Pinus sylvestrus) grows in zones 1-4.

  In 1990, the USDA prepared a map of North America depicting which areas are in which hardiness zones, based on their average annual lows (over the period 1974-86). This of course changes as the climate changes; in 2006, the Arbor Day Foundation updated the U.S. hardiness zones to reflect the most recent 15 years of data and perhaps half the U.S. (excepting California and Nevada) experienced a one zone (10oF) increase.

  The logic behind the hardiness zone definition is that even a brief exposure to a cold enough temperature will kill the plant. However, it ignores the fact that a plant may withstand a short exposure to say -5oC yet be killed if there are too many days at 0oC.

  Also, it ignores the effects of day length, summer heat, wind, and the amount and distribution of rainfall, which in turn are influenced by latitude, elevation, continental position, and mountain barriers. The American Horticultural Society has a Plant Heat Zone map; the zones are based on the average number of days per year above 30oC, thus accounting for summer heat. There are other zoning systems, that take additional factors into account, but we can't use them in LIA Europe because we lack some of the necessary data.

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  Besides the direct effects of climate on plant growth, there are also indirect effects. Plant pests are also affected by temperature; a warm winter may mean a bumper crop of insects in the spring. In late 17th-century Switzerland, cool springs led to crop losses as a result of attacks of the parasite Fusarium nivale, which is active under snow cover (LambCHMW 206).

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  Domestic animals are also affected by climate. Animals can be killed by climate extremes, especially the combination of heat and drought. Even conditions that don't kill can reduce reproduction, growth rate, and milk production.

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  Considering domesticated plants and animals together, both temperature and precipitation can have significant adverse effects. The so-called LIA-type impacts are:

  March, April: cold decreases forage for dairy animals and the volume of the grain harvest.

  July, August: rain interferes with the harvesting of crops.

  September, October: cold forces animals into the barn earlier and reduces the sugar content of vine-must; prolonged rain reduces area sown and nitrogen content of the soil (thus affecting the following year's productivity).

  Pfister2006 has combined temperature and precipitation monthly data to arrive at a "biophysical climate impact factor."

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  Fish have preferred water temperatures. During the LIA, cod and herring moved south, hurting the fisheries of Norway, Scotland and the Faeroe Islands, but benefiting the English (Mandia).

  Climate and Transportation

  In 1630, the cheapest form of transportation was by water. However, except in far northern Europe, transport was dependent on liquid water; skating or skiing on ice or snow was fine for individuals but not practical for large-scale freight movement.

  So that means that we need to ask when will geographically significant navigable rivers freeze and thaw, in which months will strategic harbors be closed by sea ice, and when will particular sea routes be endangered by icebergs.

  Rainfall can also make a difference. In some parts of the world, rivers are navigable only for part of the year. Or in some years and not others.

  Land transportation is also affected by climate. Snow can close a mountain pass, or simply make it slower to travel by road. Rainfall can turn dirt into mud, or make a ford impassable, or cause a flood that destroys a bridge.

  On the other hand, the freezing of rivers (while not good for water travel) can make river crossings easier. In 1597-8, Matteo Ricci wrote that "once winter sets in, all the rivers in northern China are frozen over so hard that navigation on them is impossible and a wagon may pass over them." (Brooks 55).

  Up-time transportation technology also has its vulnerabilities. Cold temperatures can reduce starter battery life, render fuel viscous, and cause engines to stutter. High temperatures make it easier for engines to overheat.

  Climatic interference with transportation can make it more difficult to relieve a local famine by moving in food from elsewhere.

  Climate and Communication

  Prior to the RoF, messages traveled, at least over distances beyond line-of-sight, at pretty much the same speed as people and goods. On land, the fastest communications were those provided by a post horse system, and at sea, messages could be carried by a sailing ship built for speed and not burdened with a heavy cargo. The effect of climate on these channels of communication have already been discussed in the context of transportation.

  The up-timers will be introducing radio and telegraph communications, and radio waves and electrical pulses travel at the speed of light. O
f course, as a practical matter, it takes time for an operator to convert a message into transmissible form, and, at the receiving end, for another operator to convert it back again. If the message has to be relayed, then effective transmission times are increased. But it's still much faster than horse or ship.

  Our climate is the result of the heating of the earth's land masses, oceans and atmosphere by solar radiation, coupled with the rotation of the earth about an axis tilted relative to its orbital plane.

  The amount of solar variation emitted by the sun varies, and it turns out that there's a pretty good correlation between the number of sunspots and the solar output. All else being equal (and it rarely is), if solar output decreases, so will mean global temperature.

  However, there is a more specific effect on radio communications. The solar radiation includes not only light photons, but also charged particles, and when those particles strike the earth's atmosphere, they ionize some of the air molecules. When solar output is high, the degree of atmospheric ionization is higher, and it is easier to bounce radio signals off the "ionosphere" so that they can travel longer distances. The principle is explained in much more detail in Boatright, "Radio in the 1632 Universe," Grantville Gazette 1.

  Climate and Mining

  Surface temperature doesn't have much of a direct effect on underground mining; the temperature underground is mostly a function of latitude. However, it can affect how easy it is to get miners and their goods to the mine, and to ship off the ore. A good case in point is that in the nineteenth century, cryolite could be mined in Greenland for only a small part of the year.

  Rainfall is another matter. Drainage was a serious problem in both European and Japanese mines, and I imagine that in periods of heavy rainfall, the problem was exacerbated.

  Climate and Industry

  Industrial production presupposes the existence of healthy indoor temperatures. It is already a common practice to heat homes and shops during the winters in colder regions of the world. Factories in those climes will also need heating systems, and, if it gets colder, they will require more fuel (most likely wood or coal).

  Summers in warmer regions are more of a problem, because the only form of cooling is ventilation. True air conditioning requires up-time technology. Fortunately, in those areas affected by the LIA, summer is not a major concern.

  The effect of increased rainfall is a more subtle one; more rainfall will be associated with more humidity, which means more problems with decay (wood) and rust (iron). This may increase industrial demand, but it also means that the maintenance costs will be higher.

  Climate and Warfare

  The conduct of war is also affected by climate, both indirectly and directly. If harvests are poor, it will be difficult to feed the troops and their work animals. If roads are muddy or snow-covered, troop movements will be slow. If the soldiers are not conditioned to the local climate, and properly dressed for it, there will be weather-associated deaths.

  Climate begets weather, and one of the more piquant examples of the effect of weather on warfare was the January 23, 1795 capture of the Dutch fleet by the cavalry of the French Republic. It was trapped to the lee of Texel Island by ice.

  PART II: CLIMATE IN THE 1630s (OLD TIME LINE)

  The Up-Timers' Perspective

  The up-timers are coming from a West Virginia town. While Grantville is fictional, it is based on real-life Mannington, in north central West Virginia (Marion County). Climate data for Mannington goes back to 1948, but unfortunately it's spread over three different weather stations. For nearby Fairmont, there's continuous data from a single station.

  Please note that interannual variability of even annual (let alone seasonal, monthly, or specific day of the year) temperatures is such that it is customary for weather services to calculate "climatological normals" over a thirty-year period.

  Table 1 shows the sort of climate that the up-timers of Grantville are accustomed to. From this we can estimate seasonal average temperatures as follows: winter (DJF), 31.7oF (-0.2oC); spring (MAM), 51.0 (10.6); summer (JJA), 70.5 (21.4); autumn (SON), 54.2 (12.3). The average of the daily minimums for January was 20.4oF.

  (Climatography #81, #85)

  Fairmont (ZIP code 26554) was in the 1990 USDA Plant Hardiness Zone 6A (average absolute annual minimum temperature in range -10 to -5oF, -20.6oC to -23.3oC), and in zone 6-7 of the 2006 Arbor Day Foundation update.

  In this part of West Virginia, the first freezing temperatures (end of the growing season) is typically in the first half of October, and the last freezing temperature (preceding spring planting) in the first half of May. http://www.accuracyproject.org/w-FreezeFrost.html

  A Global Overview of the LIA

  In 2002, Mann presented a figure comparing temperatures for the period 1000-2000 for eight different parts of the world. Mann considers the LIA to be 1400-1900, and my comments are based on the reconstructed annual means. I will call an LIA "low" if the temperature was less than the lowest value for that region during 1000-1400.

  Northern Hemisphere: the lows are in the late-16th, late-17th, and late-19th centuries, with highs in the early 17th and mid 18th centuries.

  West North America: the deep lows are in the late-16th and mid-19th centuries, and a shallower but broader low appears in the 17th. The highs are in the early-15th, mid-16th and late-18th centuries.

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

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

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

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

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

  Tropical Andes: the LIA really began around 1500 here, but there were no sharp lows. The lowest points are in the late-17th and late-18th centuries. The early-17th century was cooler than the 15th 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).
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  Great Britain. According to Wikipedia/River Thames Frost Fairs, in the 17th 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-18th century, and then climbed to a greater high in the early-19th century (Flohn 44; LambCPPF 462).

  Note that during the coldest parts of the LIA (which for England was the late-17th 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 17th 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 -5.84oC and -4.72oC 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).