Temperature series inferred from high-resolution pollen records from two northern italian lakes evaluated by comparison with instrumental series.

High-resolution pollen records obtained from well-dated lake sediments are exceptional proxies for palaeoenvironmental and palaeoclimate reconstructions. The availability of modern pollenclimate calibration datasets and the application of numerical techniques to the high-resolution paleoecological records allow the quantitative reconstructions of past climate parameters. Here, we present pollen-inferred summer temperature series for the last 200 years in northern Italy obtained from two published pollen records, Lago di Lavarone (Arpenti and Filippi, 2007) and Lago Grande di Avigliana (Finsinger et al., 2006), provided with good chronological control and sub-decadal sample resolution. The direct comparison between pollen-inferred temperature and site-specific instrumental series enables to discuss methodological issues and validates the pollen-based climate estimates. We find moderate to good correlation during the whole 200 years interval. The pollen-based temperatures capture the general warming of the last centuries and its intensification occurred in the last decades recorded in the instrumental series. Thanks to the sub-decadal resolution of the pollen records, the pollen-based reconstructions detect a short colder interval around 1910 AD and a warmer interval around 1940-1950 AD recorded in the instrumental data. Differences and shifts between the pollen based temperatures and the instrumental series are discussed in relation to human activities and methodological issues, such as the choice of the numerical method used to develop the pollen-climate calibration models. The pollen-based temperatures provide the base for direct comparison with other proxy-based climate reconstructions (e.g. tree-rings, chironomids).