Seebergsee, Switzerland 1000 Year Chironomid Inferred Temperature Larocque, I.; Stewart, M.M.; Quinlan, R.; Trachsel, M.; Kamenik, C.; Grosjean, M. Larocque, I. Stewart, M.M. Quinlan, R. Trachsel, M. Kamenik, C. Grosjean, M. Air Temperature Reconstruction Little Ice Age (LIA) Medieval Climate Anomaly (MCA) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized|smoothed,null,N,11-year mean (triangular)) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,year Common Era,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/reconstructions (Seebergsee>LATITUDE 46.1167>LONGITUDE 7.4667) Determining if temperatures of the last century exceed natural variability necessitates the use of high-resolution paleo- reconstructions extending beyond the instrumental data (i.e. >150 years). Although syntheses using tree-ring, stalagmite, and borehole based reconstructions are available, biological proxies preserved in lake sediments have been neglected as a source of high-resolution information on climate change. Here, we present a decadal-scale mean July air temperature reconstruction covering the past millennium from varved Seebergsee, Switzerland. This reconstruction is compared to instrumental data at local, regional and European scales, to another high-resolution chironomid-inferred temperature reconstruction from Lake Silvaplana (Switzerland), to a composite of paleo-climate reconstructions from the Greater Alpine Region and to various millennial scale climate reconstructions from the northern hemisphere. When compared to local and regional instrumental records since ca 1760 AD significant (p < 0.01) relationships (rPearson > 0.5) are obtained, suggesting that chironomids accurately register the changes in temperature for the past ca 250 years. At European scale, the Seebergsee reconstruction correlates (rPearson = 0.40; p < 0.01) with instrumental and early instrumental data back to 1500 AD. On the millennial time scale, the chironomid reconstruction of Seebergsee provides a pattern of temperature changes mirrored by the chironomid reconstruction from Silvaplana (rPearson = 0.44; p < 0.01) and the Greater Alpine Region composite of reconstructions (rPearson = 0.40; p < 0.01). This includes warmer-than-the-last- century mean July air temperatures (+1.2 °C on average) during the end of the "Medieval Climate Anomaly" (MCA) and colder-than- the-last-century temperatures (-0.5 °C on average) during the "Little Ice Age". Both chironomid reconstructions inferred a warming during the last decades, but this chironomid-inferred warming does not exceed the MCA temperatures. This result is not singular as many millennial temperature reconstructions in the northern Hemisphere do not show unprecedented warming of the last century at local/regional scale. However, the chironomid assemblages found in Seebergsee and Silvaplana since ca 1950 AD seem to be unique (i.e. they show unprecedented assemblage compositions) for the past 1000 years. STUDY NOTES: Chironomid-inferred mean July temperature from Seebergsee, Switzerland for the last 1000 years. Data are presented with 11-year triangular filter (presented in fig 4). Seebergsee, Switzerland: 46°7'N, 7°28'E NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Larocque, I. Investigator : Stewart, M.M. Investigator : Quinlan, R. Investigator : Trachsel, M. Investigator : Kamenik, C. Investigator : Grosjean, M. 2012-04-17 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12899 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.xls English https://www.ncdc.noaa.gov/paleo/study/12899 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/seebergsee2012.xls Larocque-Tobler, I., M.M. Stewart, R. Quinlan, M. Trachsel, C. Kamenik, and M. Grosjean. 2012. A last millennium temperature reconstruction using chironomids preserved in sediments of anoxic Seebergsee (Switzerland): consensus at local, regional and Central European scales. Quaternary Science Reviews, Vol. 41, 18 May 2012, pp. 49-56. http://dx.doi.org/10.1016/j.quascirev.2012.03.010 START YEAR: 1083 AD * END YEAR: 2001 AD 7.4667 46.1167 7.4667 46.1167