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Cambios inesperados en el presupuesto global de metano en los últimos 2000 años
D F Ferretti1, J B Miller, J W C White
1Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA. d.ferretti@niwa.co.nz
Science (New York, N.Y.)
|September 10, 2005
Resumen
Las mediciones de isótopos estables de carbono en núcleos de hielo antárticos revelan cambios inesperados en el presupuesto de metano durante el Holoceno preindustrial tardío. Las emisiones de la quema de biomasa fluctuaron significativamente, lo que afectó el presupuesto mundial de metano.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Química de la atmósfera La química de la atmósfera
- La geoquímica es la geoquímica.
Sus antecedentes:
- El presupuesto de metano y sus impulsores durante el Holoceno preindustrial no se comprenden completamente.
- El metano atmosférico (CH4) juega un papel importante en el sistema climático de la Tierra.
- Los isótopos estables de carbono en el metano (delta13CH4) proporcionan información crucial sobre las fuentes y sumideros de metano.
Objetivo del estudio:
- Para reconstruir el presupuesto de metano del Holoceno preindustrial tardío utilizando datos de núcleos de hielo de la Antártida.
- Para investigar las variaciones en las fuentes de metano, en particular las emisiones de quema de biomasa.
- Evaluar la influencia de las actividades humanas y el cambio climático en las emisiones de metano preindustriales.
Principales métodos:
- Análisis de isótopos estables de carbono en el metano atmosférico (delta13CH4) de un registro de núcleos de hielo antártico de 2000 años.
- Modelado de la partición de la fuente de metano para inferir cambios en las emisiones.
- Comparación de datos isotópicos con proxies conocidos del clima y la actividad humana.
Principales resultados:
- Se observaron variaciones significativas del delta13CH4 durante el período de 2000 años.
- La composición isotópica del metano se enriqueció de 0 a 1000 d.C. y se agotó de 1000 a 1700 d.C.
- La partición de fuentes modelada indica una reducción de ~40% en las emisiones de quema de biomasa entre los dos períodos.
Conclusiones:
- Las emisiones de la quema de biomasa preindustrial variaron significativamente y anteriormente se subestimaron.
- Tanto los factores antropogénicos como la variabilidad climática natural influyeron en estas emisiones.
- El presupuesto de metano durante el Holoceno preindustrial tardío fue más dinámico de lo que se suponía anteriormente.
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