The Spatio-Temporal Pattern of the Mid-Holocene Thermal Maximum

Abstract

This article presents a review of the spatio-temporal pattern of the mid-Holocene Thermal Maximum as it occurs in 60 different reconstructions of annual mean temperature from locations around the globe. The geographical coherency of multi-centennial periods with annual mean temperatures at least 1°C and 2°C above the pre-industrial (~1750 AD) equivalents are presented. Although the reconstructions show a heterogeneous temperature pattern for the period c. 10–8 ka BP, a rather coherent period of temperatures exceeding the pre-industrial ones are seen for c. 8–4 ka BP. The onset of the Neoglaciation takes place 4–3 ka BP and cumulates during the Little Ice Age (c. 1300–1900 AD). Overall, our review points towards a more homogeneous mid-Holocene Thermal Maximum than hitherto reported. However, the still limited data coverage, especially for the Southern Hemisphere, restricts the possibility to draw any firm conclusion regarding the amplitude and spatio-temporal pattern of the maximum mid- Holocene warming.