Evaluating periodicities in peat-based climate proxy records

► Climate proxy data spanning the last 4.5 ka from two peatlands in Northern Ireland are presented. ► The records contain significant periodicities of c. 1160, 540, 260, 180 and 130 years. ► Replication implies that these are a product of allogenic, climatic controls. ► The c. 1160 periodicity may reflect the persistent millennial-scale Holocene cycle. ► The 180-260 year periodicities may reflect quasi-periodic signals of the Suess solar cycle.