The Reading Palaeofire Database: an expanded global resource to document changes in fire regimes from sedimentary charcoal records

Abstract

Abstract. Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. Existing global compilations are not geographically comprehensive and do not provide consistent metadata for all sites. Furthermore, the age models provided for these records are not harmonised and many are based on older calibrations of the radiocarbon ages. These issues limit the use of existing compilations for research into past fire regimes. Here, we present an expanded database of charcoal records, accompanied by new age models based on recalibration of radiocarbon ages using IntCal20 and Bayesian age-modelling software. We document the structure and contents of the database, the construction of the age models, and the quality control measures applied. We also record the expansion of geographical coverage relative to previous charcoal compilations and the expansion of metadata that can be used to inform analyses. This first version of the Reading Palaeofire Database contains 1676 records (entities) from 1480 sites worldwide. The database (RPDv1b – Harrison et al., 2021) is available at https://doi.org/10.17864/1947.000345.

The response of wildfire regimes to Last Glacial Maximum carbon dioxide and climate

“…The climate effect was larger than the CO2 effect across all models for FS, with increases in wind, DD and DTR driving the change. BA Our model results reproduce the global reduction of biomass burning at the LGM observed from ice cores and sedimentary charcoal records (Daniau et al, 2012;Harrison et al, 2022;Power et al, 2008;Rubino et al, 2016). Some studies have indicated the occurrence of high-intensity wildfires on the Palaeo-Agulhas Plain of South Africa, tropical regions, northern Australia, and central China at the LGM (Kraaij et al, 2020;Power et al, 2008;Rowe et al, 2021;Ruan et al, 2020;M.…”

“…Changes in GPP and grass cover were responsible for the largest reductions in burning, with these vegetation effects concentrated across Africa and much of Eurasia (see Figure 5). In Amazonia, changes in DD were the most important factor, reducing Comparing the spatial patterns of the simulated BA anomalies with charcoal-based reconstructions of the sign of changes in biomass burning (RPD; Harrison et al, 2022) showed that the best overall match occurred when both the climate and CO2 effect were considered, with a success rate of ~ 39-45% depending on the climate scenario. A successful identification means that the sign of the experiment anomaly and the sign of the RPD charcoalbased reconstructions are the same.…”

“…The LGM had a generally colder and drier climate than today, with CO2 levels ~ 185 ppm. Palaeorecords show reduced vegetation productivity and forest cover Kaplan et al, 2016;Moreno et al, 2018), and ice core and sedimentary charcoal records indicate reduced biomass burning globally (Albani et al, 2018;Harrison et al, 2022;Marlon et al, 2016;Rubino et al, 2016). Although this reduction could reflect the colder and drier conditions, model experiments suggests that low CO2 also played a crucial role.…”

“…Comparisons to LGM charcoal records from the Reading Palaeofire Database (RPD) (Harrison et al, 2022) were used to examine which experiments provided the most realistic spatial patterns. Modern (MOD) climate data (daily temperature (T), daily precipitation (P), photosynthetic photon flux density (PPFD), monthly wind speeds (wind), vapour pressure deficit (VPD), monthly specific humidity (huss), cloud cover (cld), monthly pressure (Pa)) were obtained from the WFDE5 bias-adjusted ERA5 database (Cucchi et al, 2020) for 2010 to 2015.…”

“…We also compared the spatial patterns of BA, FS and FI with sedimentary charcoal data from the Reading Palaeofire Database (RPD; Harrison et al, 2022). Sedimentary charcoal records provide a record of fire activity but may reflect changes in both burnt area or completeness of combustion (Power et al, 2008) so this comparison allowed us firstly to establish which of the fire regimes properties was most closely reflected in these records and secondly which of the scenarios produced the most realistic patterns of burning.…”