Extreme sea ice events in the Chinese marginal seas during the past 2000 years

We used Chinese historical literature to examine extreme records of sea ice events in the Chinese marginal seas during the past 2000 yr. We identified a total of 6 sea ice events that occurred in the sea areas to the south of 35° N. These extreme events occurred in the winters of AD 821/822, 903/904, 1453/1454, 1493/1494, 1654/1655 and 1670/1671. According to the historical records, the southern limit of sea ice in the Chinese marginal seas should be in Hangzhou Bay (30-31° N), and most probably near Haiyan County in Zhejiang Province (30.5° N). The sea ice events of 1453/1454 and 1654/1655 were synchronous with the freezing events of Taihu Lake, and the sea ice event of 1670/1671 was synchronous with the freezing event of the lower reaches of the Yangtze River. However, none of the sea ice events was synchronous with the abnormally early freezing dates of Suwa Lake in Japan or the extreme freezing events of Venice Lagoon in Italy. Although all of the sea ice events occurred in a cold climate on a 30 yr timescale, they were not synchronous with the extreme cold winters of other sites in the northern hemisphere. However, the sea ice event of 1453/1454 may have been related to the ca. 1453 Kuwae eruption. Our findings increase our understanding of both regional environmental change in the Chinese marginal seas and the regional nature of global climate change.