Dark Ages Cold Period: A literature review and directions for future research

Several late Quaternary studies have recorded cold and disturbed climates centred during the mid-first millennium AD and discussed these conditions
under the term ‘Dark Ages Cold Period’ (DACP). A review of 114 palaeoclimate papers indicated that cold climates were common in the Northern
Hemisphere between AD 400 and 765. There are also suggestions that some regions may have been relatively wet during the DACP, while those around
the Mediterranean and the China/Tibetan Plateau indicate coinciding droughts. A set of environmental responses, however, indicate a delayed DACP
interval (AD 509–865) postdating the actual climate signal. Previously, the DACP has been linked with the North Atlantic ice-rafting event at about 1400
years ago, while some evidence suggests an involvement of the North Atlantic Oscillation and/or El Niño–Southern Oscillation. More recently, another
proposed phase of widespread cooling, the ‘Late Antique Little Ice Age’ (LALIA), overlaps with the DACP and has been tentatively linked with volcanic
aerosol and solar irradiance variations reinforcing the climatic downturn since AD 536. Importantly, a higher number of proxy records extending over
the first millennium AD is required for more rigorous assessments of climate variability and the forcing during these centuries and to disentangle the
DACP and LALIA fingerprints in the proxy data, particularly to determine whether the DACP and the LALIA are distinct features. Also a richer network
of both climate and environmental proxies is needed to evaluate the human–environment interactions, during the historical Migration Period, and thus
through the DACP.