Climate and sea level variability on a centennial time scale over the last 1500 years as inferred from the Coastal Peatland of Puck Lagoon (southern Baltic Sea)

The climate variability and related sea-level changes during the Holocene are still under discussion, especially in a regional context. Very little information comes from the southern and south-eastern Baltic coast. The aim of the paper is to gain insight on the history of regional environmental changes, particularly sea-level and storminess, and their driving forces. The investigations were located on a peatland on the coast of Puck Lagoon (Gulf of Gdansk, southern Baltic Sea). The analysis of peat core comprised: radiocarbon dating, analysis of stable isotopes(18)O and(13)C and chemical components, as well as palynological and diatomic studies. Results showed the 1.0 m peat section accumulated over 1500 years, with a time resolution of 100 years per sample. The average water level in the Puck Lagoon rose by ca. 0.85 m during the last 1500 years in a cyclic mode, with a period cycle of ca. 600-550 years and an amplitude not exceeding 0.5 m. The accelerated sea level rise and frequent storminess occurred during the first half of the Dark Ages (1500-1300 years b2k) and LIA (750-450 years b2k) and since the beginning of the 20th century. Recognized environmental changes are well correlated with both temperature changes in the North Atlantic and changes in total solar irradiance, suggesting synchronous Northern Hemisphere-wide fluctuations. The solar forcing was an important constituent of natural climate variability in the past and of forcing climate warming during modern times - after the Little Ice Age.