RESEARCH PAPER Bimodal fire regimes unveil a global-scale anthropogenic fingerprint Akli Benali 1 | Bernardo Mota 2 | Nuno Carvalhais 3,4 | Duarte Oom 1 | Lee M. Miller 3 | Manuel L. Campagnolo 1 | Jos  e M. C. Pereira 1 1 Centro Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisboa, 1349-017, Portugal 2 Department of Geography, King’s College London, Strand, London WC2R 2LS, UK 3 Max Planck Institute for Biogeochemistry, Hans Knoell Strasse 10, Jena 07745, Germany 4 Departamento de Ci^ encias e Engenharia do Ambiente, DCEA, Faculdade de Ci^ encias e Tecnologia, FCT, Universidade Nova de Lisboa, Caparica 2829-516, Portugal Correspondence Akli Benali, Centro Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisboa 1349-017, Portugal. Email: aklibenali@gmail.com Present addresses Bernardo Mota, Institute for Environment and Sustainability, Joint Research Centre, European Commission, Via E. Fermi 2749, 21027 Ispra (VA), Italy. Lee M. Miller, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. Editor: Ben Poulter Funding information Fundaç~ ao Ci^ encia Tecnologia, grant numbers: PD/BD/52692/2014, UID/AGR/ 00239/2013 Abstract Aim: While fire is recognized as an integral part of the Earth system, the ability of humans to shape fire regimes both spatially and temporally remains poorly understood. Our goals were to identify the extent of fire regimes exhibiting two annual fire seasons and to investigate the envi- ronmental correlates of such regimes at the global scale. Location: All areas of the globe exhibiting relevant fire activity, at 0.5  spatial resolution. Time period: 2002-2012. Major taxa studied: (not applicable). Methods: The modality of fire seasonality at the global scale was classified using a 10-year record of satellite-derived fire activity and model fitting of circular statistical distributions. The main envi- ronmental correlates controlling global fire regimes were then analysed over bimodal and unimodal areas using the Kolmogorov–Smirnov test. Results: About 25% of the global land surface with relevant fire activity has two significantly dis- tinct fire seasons per year, with at least one of these seasons occurring under sub-optimal fire weather conditions. In these bimodal areas, population density and the fraction of fires occurring in actively managed land, especially in croplands and pastures, are significantly higher than in neighbouring unimodal areas. Results reveal that through these land-use and management prac- tices humans have a strong influence on global patterns of fire seasonality. Main conclusions: We identified a bimodal seasonality pattern, previously unreported at the global scale, and show that it reveals an anthropogenic fingerprint on fire regimes. Insights into where and when fire is actively employed as a land management tool enhance our understanding of the role of fire in the Earth system, and highlight the need to better understand how fire prac- tices may change in the future. KEYWORDS anthropogenic fires, climatic suitability, fire season, human activities, land management, MODIS active fire counts 1 | INTRODUCTION Fire has been recognized as an integral Earth system process linking and influencing biogeochemical cycles, anthropogenic activities and vegetation dynamics at multiple spatial and temporal scales (Bond, Woodward, & Midgley, 2005; Bowman et al., 2009). Despite its impor- tance, the fundamental role of fire in the Earth system, along with its causes and consequences, is still poorly understood (Archibald, Lehmann, G omez-Dans, & Bradstock, 2013; McWethy et al., 2013). Fire regimes can be characterized by the frequency, intensity, sea- sonality, extent and type of fire at different spatial and temporal scales (Archibald et al., 2013). Climate, fuels and ignitions are the main drivers Global Ecol Biogeogr. 2017;26:799–811. wileyonlinelibrary.com/journal/geb V C 2017 John Wiley & Sons Ltd | 799 Received: 5 October 2015 | Revised: 9 February 2017 | Accepted: 16 February 2017 DOI: 10.1111/geb.12586