Assessing changes in global fire regimes
Authors: Sayedi Sayedeh Sara , Abbott Benjamin W , Vannière Boris , Leys Bérangère , Colombaroli Daniele , Romera Graciela Gil , Słowiński Michał , Aleman Julie C. , Blarquez Olivier , Feurdean Angelica , Brown Kendrick , Aakala Tuomas , Alenius Teija , Allen Kathryn , Andric Maja , Bergeron Yves , Biagioni Siria , Bradshaw Richard , Bremond Laurent , Brisset Elodie , Brooks Joseph , Bruegger Sandra , Brussel Thomas , Cadd Haidee , Cagliero Eleonora , Carcaillet Christopher , Carter Vachel , Catry Filipe X. , Champreux Antoine , Chaste Emeline , Chavardès Raphaël Daniel , Chipman Melissa , Conedera Marco , Connor Simon , Constantine Mark , Mustaphi Colin Courtney , Dabengwa Abraham N , Daniels William , De Boer Erik , Dietze Elisabeth , Estrany Joan , Fernandes Paulo , Finsinger Walter , Flantua Suzette , Fox-Hughes Paul , Gaboriau Dorian M , Gayo Eugenia M. , Girardin Martin.P , Glenn Jeffery , Glückler Ramesh , González-Arango Catalina , Groves Mariangelica , Hamilton Rebecca Jenner , Hamilton Douglas , Hantson Stijn , Hapsari K. Anggi , Hardiman Mark , Hawthorne Donna , Hoffman Kira , Iglesias Virginia , Inoue Jun , Karp Allison T , Krebs Patrik , Kulkarni Charuta , Kuosmanen Niina , Lacourse Terri , Ledru Marie-Pierre , Lestienne Marion , Long Colin , López-Sáez José Antonio , Loughlin Nicholas , Lynch Elizabeth , Niklasson Mats , Madrigal Javier , Maezumi S. Yoshi , Marcisz Katarzyna , Meyer Grant , Mariani Michela , McWethy David , Molinari Chiara , Montoya Encarni , Mooney Scott , Morales-Molino Cesar , Morris Jesse , Moss Patrick , Oliveras Imma , Pereira José Miguel , Pezzatti Gianni Boris , Pickarski Nadine , Pini Roberta , Robin Vincent , Rehn Emma , Remy Cecile , Rius Damien , Ruan Yanming , Rudaya Natalia , Russell-Smith Jeremy , Seppä Heikki , Shumilovskikh Lyudmila , Sommers William T. , Tavşanoğlu Çağatay , Umbanhowar Charles , Urquiaga Erickson , Urrego Dunia , Vachula Richard , Wallenius Tuomo , You Chao , Daniau Anne-Laure 
Published: February 2023

Human activity has fundamentally altered wildfire on Earth, creating serious consequences for human health, global biodiversity, and climate change. However, it remains difficult to predict fire interactions with land use, management, and climate change, representing a serious knowledge gap and vulnerability. We used expert assessment to combine opinions about past and future fire regimes from 98 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Respondents indicated that direct human activity was already influencing wildfires locally since at least~12,000 years BP, though natural climate variability remained the dominant driver of fire regime until around 5000 years BP. Responses showed a ten-fold increase in the rate of wildfire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in fire frequency, severity, and/or size in all biomes except grassland ecosystems. Fire regime showed quite different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher greenhouse gas emission scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, concluding that management options are seriously constrained under higher emission scenarios.