Over de Medieval Warm Period en de Little Ice Age. (Let op: tekst is lang en in 't Engels, en 'k heb tijd noch goesting die volledig te vertalen).
Volledige Bron: Jones, P.D., and M.E. Mann (2004), Climate over past millennia, Rev. Geophys., 42, RG2002, doi:10.1029/2003RG000143
[22] 1. River Thames freeze-overs (and sometimes frost fairs) only occurred 22 times between 1408 and 1814 [Lamb, 1977] when the old London Bridge constricted flow through its multiple piers and restricted the tide with a weir. After the bridge was replaced in the 1830s, the tide came farther upstream, and freezes no longer occurred, despite a number of exceptionally cold winters. The winter of 1962/1963, for example, was the third coldest in the central England temperature (CET) record (the longest instrumental record anywhere in the world extending back to 1659 [Manley, 1974; Parker et al., 1992]), yet the river only froze upstream of the present tidal limit at Teddington. The CET record clearly indicates that Thames (London) “frost fairs” provide a biased account of British climate changes (let alone larger-scale changes, see Figure 2c) in past centuries.
[23] 2. Monks in medieval England grew vines as wine was required for sacramental purposes. With careful husbandry, vines can be grown today, and indeed, vineyards are found as far north as southern Yorkshire. There are a considerably greater number of active vineyards in England and Wales today (roughly 350) than recorded during medieval times (52 in the Domesday Book of A.D. 1086). Vine growing persisted in England throughout the millennium. The process of making sparkling wine was developed in London (by Christopher Merret) in the 17th century, fully 30 years before it began in the Champagne region of France. Thus the oft cited example of past vine growing in England reflects little, if any, on the relative climate changes in the region since medieval times.
[24] 3. Iceland was settled mainly from Norway and the northern British Isles beginning ~A.D. 871. The further migration to SW Greenland approximately one century later, by a small group of Icelanders, was the result primarily of a political and economic need to leave Iceland [Ogilvie and Jónsson, 2001]. Climate was not a factor in their decision despite claims otherwise that still appear in the literature [Soon and Baliunas, 2003; Soon et al., 2003]. The SW Greenland settlements survived for many centuries, but in the mid-14th century the more marginal and more northerly located Western Settlement was abandoned. There were a number of reasons for this, including culture and economic factors. However, it seems likely that climate did play a part in the abandonment. The focus of their economy on animal husbandry denied them the advantages of hunting marine and other mammals that ensured the survival of their Inuit neighbors. A series of unusually late springs and cold summers, for example, may have helped to make a marginal situation untenable [Barlow et al., 1997]. The more southerly Eastern Settlement survived to around the mid-15th century [Buckland et al., 1996]. Related myths exist for the North American continent. Overland and Wood [2003], for example, have recently demonstrated that, despite past claims that the extreme cold of the “Little Ice Age” (LIA) impeded the navigation of a Northwest Passage in the Canadian Arctic during the early 19th century, an exhaustive study of 19th century explorer logs for the region yields no evidence of unusually cold conditions.
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