| Medieval Warm Period |
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Initial research on the MWP and the following Little Ice Age (LIA) was largely done in Europe, where the phenomenon was most obvious and clearly documented. It was initially believed that the temperature changes were global. However, this view has been questioned; the 2001 IPCC report summarises this research, saying: "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries" {Link without Title} . During this time took advantage of ice-free seas to colonize Greenland and other outlying lands of the far north. The period was followed by the Little Ice Age, a period of cooling that lasted until the 19th Century when the current period of Global Warming began. It has been noted that most paleoclimatologists developing regionally specific climate reconstructions of past centuries conventionally label their coldest interval as "LIA" and their warmest interval as the "MWP". Others follow the convention and when a significant climate event is found in the "LIA" or "MWP" time frames, associate their events to the period. Some "MWP" events are thus wet events or cold events, particularly in central Antarctica where climate patterns opposite to the North Atlantic area have been noticed. Climate events The Medieval Warm Period partially coincides in time with the peak in Solar Activity named the Medieval Maximum (AD 1100 – 1250 ). In of the lower Hudson Valley show a dry Medieval Warm period from AD 800–1300. {Link without Title} Prolonged droughts affected many parts of the western – 300 , 850 – 1200 , and post- 1800 AD . A Radiocarbon -dated box core in the Sargasso Sea shows that sea surface temperature was approximately 1°C cooler than today approximately 400 years ago (the Little Ice Age) and 1700 years ago, and approximately 1°C warmer than today 1000 years ago (the Medieval Warm Period) {Link without Title} . However, all the reconstructions, as shown above, appear to indicate that it was not. The climate in equatorial east Africa has alternated between drier than today, and relatively wet. The drier climate took place during the Medieval Warm Period (~AD 1000 – 1270 ) {Link without Title} . An , nicely illustrating the fact that "MWP" is a moveable term, and that during the "warm" period there were, regionally, periods of both warmth and cold. Corals in the tropical Pacific ocean suggest that relatively cool, dry conditions may have persisted early in the millennium, consistent with a La Niña -like configuration of the ENSO patterns {Link without Title} . Adhikari and Kumon (2001) in investigating sediments in Lake Nakatsuna in central Japan have verified there the existence of both the Medieval Warm period and the Little Ice Age. {Link without Title} For further discussion of regional and global temperature variations see: Temperature Record . See also References External links
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