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- ItemRecent global and regional trends in burned area and their compensating environmental controls(Bristol : IOP Publishing, 2019) Forkel, Matthias; Dorigo, Wouter; Lasslop, Gitta; Chuvieco, Emilio; Hantson, Stijn; Heil, Angelika; Teubner, Irene; Thonicke, Kirsten; Harrison, Sandy P.The apparent decline in the global incidence of fire between 1996 and 2015, as measured by satellite-observations of burned area, has been related to socioeconomic and land use changes. However, recent decades have also seen changes in climate and vegetation that influence fire and fire-enabled vegetation models do not reproduce the apparent decline. Given that the satellite-derived burned area datasets are still relatively short (<20 years), this raises questions both about the robustness of the apparent decline and what causes it. We use two global satellite-derived burned area datasets and a data-driven fire model to (1) assess the spatio-temporal robustness of the burned area trends and (2) to relate the trends to underlying changes in temperature, precipitation, human population density and vegetation conditions. Although the satellite datasets and simulation all show a decline in global burned area over ~20 years, the trend is not significant and is strongly affected by the start and end year chosen for trend analysis and the year-to-year variability in burned area. The global and regional trends shown by the two satellite datasets are poorly correlated for the common overlapping period (2001–2015) and the fire model simulates changes in global and regional burned area that lie within the uncertainties of the satellite datasets. The model simulations show that recent increases in temperature would lead to increased burned area but this effect is compensated by increasing wetness or increases in population, both of which lead to declining burned area. Increases in vegetation cover and density associated with recent greening trends lead to increased burned area in fuel-limited regions. Our analyses show that global and regional burned area trends result from the interaction of compensating trends in controls of wildfire at regional scales.
- ItemSISALv2: A comprehensive speleothem isotope database with multiple age-depth models(Katlenburg-Lindau : Copernics Publications, 2020) Comas-Bru, Laia; Rehfeld, Kira; Roesch, Carla; Amirnezhad-Mozhdehi, Sahar; Harrison, Sandy P.; Atsawawaranunt, Kamolphat; Ahmad, Syed Masood; Brahim, Yassine Ait; Baker, Andy; Bosomworth, Matthew; Breitenbach, Sebastian F.M.; Burstyn, Yuval; Columbu, Andrea; Deininger, Michael; Demény, Attila; Dixon, Bronwyn; Fohlmeister, Jens; Hatvani, István Gábor; Hu, Jun; Kaushal, Nikita; Kern, Zoltán; Labuhn, Inga; Lechleitner, Franziska A.; Lorrey, Andrew; Martrat, Belen; Felipe Novello, Valdir; Oster, Jessica; Pérez-MejÃas, Carlos; Scholz, Denis; Scroxton, Nick; Sinha, Nitesh; Ward, Brittany Marie; Warken, Sophie; Zhang, Haiwei; SISAL Working Group membersCharacterizing the temporal uncertainty in palaeoclimate records is crucial for analysing past climate change, correlating climate events between records, assessing climate periodicities, identifying potential triggers and evaluating climate model simulations. The first global compilation of speleothem isotope records by the SISAL (Speleothem Isotope Synthesis and Analysis) working group showed that age model uncertainties are not systematically reported in the published literature, and these are only available for a limited number of records (ca. 15 %, n = 107=691). To improve the usefulness of the SISAL database, we have (i) improved the database's spatiooral coverage and (ii) created new chronologies using seven different approaches for age depth modelling. We have applied these alternative chronologies to the records from the first version of the SISAL database (SISALv1) and to new records compiled since the release of SISALv1. This paper documents the necessary changes in the structure of the SISAL database to accommodate the inclusion of the new age models and their uncertainties as well as the expansion of the database to include new records and the qualitycontrol measures applied. This paper also documents the age depth model approaches used to calculate the new chronologies. The updated version of the SISAL database (SISALv2) contains isotopic data from 691 speleothem records from 294 cave sites and new age depth models, including age depth temporal uncertainties for 512 speleothems. SISALv2 is available at https://doi.org/10.17864/1947.256 (Comas-Bru et al., 2020a). © 2020 Author(s).