1. Wildfire activity enhanced during phases of maximum orbital eccentricity and precessional forcing in the Early Jurassic
- Author
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Micha Ruhl, Luke Mander, Jean-François Deconinck, Sarah J. Baker, Stephen P. Hesselbo, Claire M. Belcher, Teuntje P. Hollaar, wildFIRE Lab, Hatherly Laboratories, University of Exeter, Camborne School of Mines (CSM-UE), Environment and Sustainability Institute [Penryn, UK], Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Department of Environment, Earth and Ecosystems [Open University], The Open University [Milton Keynes] (OU), Department of Geology [Dublin], Trinity College Dublin, Funded by the Natural Environment Research Council (NERC) (grant number NE/N018508/1), the International Continental Scientific Drilling Program (ICDP), the University of Exeter, and NERC (NE/L501669/1)., and Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement
- Subjects
Biogeochemical cycle ,QE1-996.5 ,010504 meteorology & atmospheric sciences ,Fire regime ,Orbital forcing ,Geology ,Vegetation ,Forcing (mathematics) ,15. Life on land ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,Palynofacies ,Environmental sciences ,13. Climate action ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy ,General Earth and Planetary Sciences ,Environmental science ,Sedimentary rock ,GE1-350 ,Water cycle ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Fire regimes are changing due to both anthropogenic climatic drivers and vegetation management challenges, making it difficult to determine how climate alone might influence wildfire activity. Earth has been subject to natural-background climate variability throughout its past due to variations in Earth’s orbital parameters (Milkankovitch cycles), which provides an opportunity to assess climate-only driven variations in wildfire. Here we present a 350,000 yr long record of fossil charcoal from mid-latitude (~35°N) Jurassic sedimentary rocks. These results are coupled to estimates of variations in the hydrological cycle using clay mineral, palynofacies and elemental analyses, and lithological and biogeochemical signatures. We show that fire activity strongly increased during extreme seasonal contrast (monsoonal climate), which has been linked to maximal precessional forcing (boreal summer in perihelion) (21,000 yr cycles), and we hypothesize that long eccentricity modulation further enhances precession-forced fire activity. Increased fire activity in the Early Jurassic is related to changes in the hydrological cycle driven by enhanced seasonality due to orbital forcing, according to a mid-latitude sedimentary charcoal record spanning 350,000 years.
- Published
- 2021