The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period

Abstract

Abstract. Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st-century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were sufficiently large to have had a potential feedback through changes in albedo and greenhouse gas emissions on climate. Previous reconstructions of vegetation and fire changes during the D-O cycles used independently constructed age models, making it difficult to compare the changes between different sites and regions. Here, we present the ACER (Abrupt Climate Changes and Environmental Responses) global database, which includes 93 pollen records from the last glacial period (73-15 ka) with a temporal resolution better than 1000 years, 32 of which also provide charcoal records. A harmonized and consistent chronology based on radiometric dating ( 14 C, 234 U/ 230 Th, optically stimulated luminescence (OSL), 40 Ar/ 39 Ar-dated tephra layers) has been constructed for 86 of these records, although in some cases additional information was derived using common control points based on event stratigraphy. The ACER database compiles metadata including geospatial and dating information, pollen and charcoal counts, and pollen percentages of the characteristic biomes and is archived in Microsoft Access TM at https://doi.org/10.1594/PANGAEA.870867.

Pollen from the Deep-Sea: A Breakthrough in the Mystery of the Ice Ages

“…Preliminary comparison between European margin and terrestrial pollen records across Europe roughly confirms the contrasting latitudinal response over Europe to the D-O warming events despite the independent and sometimes uncertain chronologies of individual records ( Fletcher et al, 2010 ). A more in-depth comparison of these pollen records is in progress based on the harmonized chronology recently developed in the framework of the INQUA International Focus Group (IFG) ACER project ( Sánchez Goñi et al, 2017 ).…”

Aerosol-Climate Interactions During the Last Glacial Maximum

“…In synthesis, the overall knowledge on LGM carbonaceous aerosol is very limited. By combining information from the source of fires with information of past vegetation [138] and linking with past and modern data from sinks like snow and ice [134], we might have the tools to evaluate and constrain models simulating past fire activity, hence potentially the emissions of carbonaceous aerosols from fire [136,139,140] and vegetation [137]. Additional information is therefore needed, to provide a constraint on the sinks of carbonaceous aerosols, from polar (and potentially some alpine) ice cores spanning the LGM.…”

Regional impacts of climate change and its relevance to human evolution

“…Margari et al, 2010;Oliveira et al, 2017;Sanchez Goñi et al, 2008, 2016b. For Asia, the best documented millennial scale climatic variability is provided by speleothems (Cheng et al, 2016;Wang et al, 2008) and loess sequences (Li et al, 2019), no pollen sequence has been published thus far (Sanchez Goñi et al, 2017). The Asian records show respectively alternating increasing and decreasing precipitation, as the result of stronger and weaker influence of summer monsoon in the south (Cheng et al, 2016) and the westerlies in the north (Li et al, 2019), concomitant with warming and cooling D-O events in the Greenland and North Atlantic European regions including the eastern Mediterranean (Bar-Matthews et al, 1999; Figure 5b).…”

“…Since the identification of these millennial-scale climate changes in the atmosphere of Greenland, D-O cycles, and in the North Atlantic Ocean, HEs, the terrestrial palaeoclimatic community has focused its efforts on investigating the regional expression of this variability (e.g. Fleitmann et al, 2009;Sanchez Goñi et al, 2017;Wang et al, 2001). The impact of climate changes on African and Eurasian ecosystems A wide array of regional palaeoclimatic records ( Figure 3 and Table 1 of the Supplementary Material) show that global orbital and millennial scale climate changes were associated with shifts in the direction and intensity of the north and south westerlies that control the precipitation, and to a lesser extent temperature, from subtropical to high latitudes of both hemispheres (Blome et al, 2012;Li et al, 2019;Sánchez Goñi et al, 2016b;Urrego et al, 2015).…”