Multi-proxy reconstruction of Arctic summer temperatures over the past 1400 years

Abstract

ABSTRACT: A new multi-proxy summer (June to August) temperature reconstruction for the Arc-tic region (60 to 90°N) with annual resolution over the past 1400 yr is presented. The reconstruc-tion is performed using a novel ensemble method, Ensemble-LOC, designed to preserve low-frequency variability and minimize the influence of the “spurious correlation” between the proxyand instrumental data. The reconstruction is based on a set of 22 proxy records with annual reso-lution. We find clear evidences for a cold anomaly AD ~630 to 770 related to the Dark Age ColdPeriod, a warm anomaly ~950 to 1050 related to the Medieval Climate Anomaly, and a cold anom-aly ~1200 to 1900 related to the Little Ice Age. The strong 20th century warming is also evident.There are 3 different and distinct warm periods occurring during the Little Ice Age: 1470−1510,1550−1570, and 1750−1770. However, about half of the total input proxies are not used in the largemajority of the reconstructions. We still need additional proxy records from the Arctic region withannual resolution and a strong response to local temperature to further verify the results of thisstudy and in order to investigate possible spatial patterns of past Arctic temperature variability.KEY WORDS: Climate change · Global warming · Paleoclimatology · Arctic · Medieval ClimateAnomaly · Little Ice Age · Annual resolution