Interglacial and glacial variability from the last 800 ka in marine, ice and terrestrial archives

Abstract

Abstract. We have compiled 37 ice, marine and terrestrial palaeoclimate records covering the last 800 000 years in order to assess the pattern of glacial and interglacial strength, and termination amplitude. Records were selected based on their length, completeness and resolution, and their age models were updated, where required, by alignment to the LR04 benthic δ18O stack. The resulting compilation allows comparison of individual glacial to interglacial transitions with confidence, but the level of synchronisation is inadequate for discussion of temporal phasing. The comparison of interglacials and glacials concentrates on the peaks immediately before and after terminations; particularly strong and weak glacials and interglacials have been identified. This confirms that strong interglacials are confined to the last 450 ka, and that this is a globally robust pattern; however weak interglacials (i.e. marine isotope stage 7) can still occur in this later period. Strong glacial periods are also concentrated in the recent half of the records, although marine isotope stage 16 is strong in many δ18O records. Strong interglacials, particularly in the marine isotopic records, tend to follow strong glacials, suggesting that we should not expect interglacial strength to be strongly influenced by the instantaneous astronomical forcing. Many interglacials have a complex structure, with multiple peaks and troughs whose origin needs to be understood. However this compilation emphasises the under-representation of terrestrial environments and highlights the need for long palaeoclimate records from these areas. The main result of this work is the compiled datasets and maps of interglacial strength which provide a target for modelling studies and for conceptual understanding.