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.