Orbital-scale climate forcing of grassland burning in southern Africa
| Type | Article | ||||||||
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| Date | 2013-03 | ||||||||
| Language | English | ||||||||
| Author(s) | Daniau Anne-Laure1, 2, 3, Goni Maria Fernanda Sanchez2, Martinez Philippe1, Urrego Dunia H.1, 2, 3, Bout-Roumazeilles Viviane4, Desprat Stephanie2, Marlon Jennifer R.5 | ||||||||
| Affiliation(s) | 1 : Univ Bordeaux 1, CNRS, UMR 5805, F-33400 Talence, France. 2 : Ecole Prat Hautes Etud, UMR 5805, F-33400 Talence, France. 3 : CNRS, UMR 5199, F-33400 Talence, France. 4 : Univ Lille 1, CNRS, Geosyst UMR 8217, F-59655 Villeneuve Dascq, France. 5 : Yale Univ, Sch Forestry & Environm Studies, New Haven, CT 06511 USA. |
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| Source | Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2013-03 , Vol. 110 , N. 13 , P. 5069-5073 | ||||||||
| DOI | 10.1073/pnas.1214292110 | ||||||||
| WOS© Times Cited | 104 | ||||||||
| Abstract | Although grassland and savanna occupy only a quarter of the world's vegetation, burning in these ecosystems accounts for roughly half the global carbon emissions from fire. However, the processes that govern changes in grassland burning are poorly understood, particularly on time scales beyond satellite records. We analyzed microcharcoal, sediments, and geochemistry in a high-resolution marine sediment core off Namibia to identify the processes that have controlled biomass burning in southern African grassland ecosystems under large, multimillennial-scale climate changes. Six fire cycles occurred during the past 170,000 y in southern Africa that correspond both in timing and magnitude to the precessional forcing of north-south shifts in the Intertropical Convergence Zone. Contrary to the conventional expectation that fire increases with higher temperatures and increased drought, we found that wetter and cooler climates cause increased burning in the study region, owing to a shift in rainfall amount and seasonality (and thus vegetation flammability). We also show that charcoal morphology (i.e., the particle's length-to-width ratio) can be used to reconstruct changes in fire activity as well as biome shifts over time. Our results provide essential context for understanding current and future grassland-fire dynamics and their associated carbon emissions. | ||||||||
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