Multi-archive summer temperature reconstruction for the European Alps, AD 1053–1996

We present a multi-archive, multi-proxy summer temperature reconstruction for the European Alps covering the period AD 1053e1996 using tree-ring and lake sediment data. The new reconstruction is based on nine different calibration approaches and errors were estimated conservatively. Summer temperatures of the last millennium are characterised by two warm (AD 1053e1171 and 1823e1996) and two cold phases (AD 1172e1379 and 1573e1822). Highest pre-industrial summer temperatures of the 12th century were 0.3 � C warmer than the 20th century mean but 0.35 � C colder than proxy derived