medieval-atlas/introductory/22

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Climatic changes The climax of the Little Ice Age Although there were some variations, overall the next ISO years in all parts of the world saw a substantially colder regime than now, with phases representing the coldest regimes since the last Ice Age ended ten thousand years ago. Broadly, from the 1550s until 1700 the severity in Scotland tended to involve a high frequency of anticyclones centred north of 60° north, the lati tude of Shetland, with winds from the north-east, and south east ones from Europe to the south of that latitude. The northeast winds brought polar, air and in the winter-the south-east ..., ones entrained air from the rapidly cooling continental interior. r--::;ree':5. +--I \ \ The heat-bank of the North Atlantic Ocean soon be-~! '7/Q~Q' ......... -tgan to cool down. By the 1580s, in several summers navigators "f...... / .lOc:t --r found the seas between Iceland and Greenland impassable be-.... 'I I I cause of sea ice. The Arctic water spread right across the North" ~ctic'C. Atlantic, with several consequences for Scotland's climate in / 'i -l!cl~\_ the late sixteenth and seventeenth centuries. Thus the enhanced 1-_ _ thermal gradient between latitudes 50 and 65 north created cy-ice1a 650 1clonic wind storms which could exceed most of those of the 'Id J I present century, with sandblows transforming landscapes at ...... / Culbin and Udal. This strengthened gradient implicit in the low I ~ sea temperatures, with temperatures depressed significantly far.1t/,'1 '- Q~r ther in parts of Scotland than in central England. (IC -+- OCe rlZ Intermissions Although in general the conditions for agriculturalists from the __ 1550s on through into the eighteenth century were less propi---t --tious than the first half of the sixteenth century, they were not I always of unmitigated harshness. Around 1670 however the c1i-/ mate deteriorated seriously again. The most severe phase of the Little Ice Age 1--SOC)"""" The final decades of the seventeenth century are now widely agreed to have been the harshest phase of the Little Ice Age, for most areas of the world. In Scotland as in many other areas, it was not only winter which became harder. Cool summers caused. -4Sll"- harvest failures, and clusters of these brought disaster to subsistence farmers by forcing them to eat their reserves of seed corn, thus leaving them with nothing to plant for later years. Between 1693 and 1700, the harvests failed in seven years out of eight in many upland areas. Remission / The opening of the eighteenth century, leading up to the Union of the parliaments when coverage of this atlas ends, brought a welcome remission. Soon after 1700 around the world there was a widespread and rapid shift to warmer conditions. Even in this warming period however there were severe winters and poor harvests, and the Age of Improvement was not to prove an easy one for Scottish farmers as the harsh conditions returned in the later part of the eighteenth century. 8000 7000 6000 5000 4000 1000 BC 0 AD 1000 2000 D 1-··00 Climatic Optimum Time scale: the post-glacial period, conventionally of 10,300 years 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 I.I •! - Warm Phase Lit tie Ice Age Time scale: AD 700 to 1700 lAM

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