Fennoscandia 7500Yr Pollen-TreeRing July Temperature Reconstructions Helama, S.; Seppä, H.; Bjune, A.E.; Birks, H.J.B. Helama, S. Seppä, H. Bjune, A.E. Birks, H.J.B. Air Temperature Reconstruction PAGES 2k Network PAGES Arctic 2k earth science/paleoclimate/climate reconstructions|pollen|tree ring (temperature,null,null,degree Celsius,Jul,climate reconstructions|pollen|tree ring,anomalized,null,N,anomalized from 1950-2000 mean) earth science/paleoclimate/climate reconstructions|pollen|tree ring (age,null,null,year Common Era,null,climate reconstructions|pollen|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (temperature,null,null,degree Celsius,Jul,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/paleolimnology (Fennoscandia>LATITUDE >LONGITUDE ) A new palaeoclimatic reconstruction of mid-summer (July) temperatures for the last 7.5 ka in northern Fennoscandia is presented. It is based on two botanical proxies: spectra of fossil pollen and tree rings of Scots pine logs recovered from lacustrine sediments in the Arctic tree-line region. A newly developed method of proxy fusion is used to integrate the proxy-specific reconstructions of past summer temperature variability based on the pollen-stratigraphic and dendroclimatic data. The rationale behind the method is that the two proxies are likely to be connected to climate variability in a timescale-dependent fashion and, accordingly, the new reconstruction makes use of the low- and high-frequencies from pollen-stratigraphic and tree-ring data, respectively. The most prominent features of the new reconstruction are: (1) the long-term decline of temperatures by 2.0°C over the past 7.5 ka, (2) the mid-Holocene warmth culminating between 5 and 4 ka as a deviation from the cooling trend, (3) the Little Ice Age cool phase between 0.7 and 0.1 ka, and (4) the subsequent warming during the past century. These periods are superimposed on year-to-year variations in climate as dated to calendar-year accuracy by dendrochronology. Within the modern period, the years 1934 and 1937 are among the warmest, and the years 1903 and 1910 are among the coldest summers in the context of the past 7.5 ka. On average, the reconstructed Holocene climate was approximately 0.85°C warmer than the twentieth century. STUDY NOTES: Pollen data from 11 lakes in northern Fennoscandia, plus July pollen/tree-ring temperature reconstruction for the past 7500 years. Northern Fennoscandia: ~66°-70°N, ~14°-35°E NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Helama, S. Investigator : Seppä, H. Investigator : Bjune, A.E. Investigator : Birks, H.J.B. 2012-06-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13119 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.xls English https://www.ncdc.noaa.gov/paleo/study/13119 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/fennoscandia2012temperature.xls Helama, S., H. Seppä, A.E. Bjune, and H.J.B. Birks. 2012. Fusing pollen-stratigraphic and dendroclimatic proxy data to reconstruct summer temperature variability during the past 7.5 ka in subarctic Fennoscandia. Journal of Paleolimnology, Vol. 48, No. 1, June 2012, pp. 275-286. DOI: 10.1007/s10933-012-9598-1 START YEAR: -5500 AD * END YEAR: 2005 AD 14.05 66.42 35.32 70.83