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Los antiguos depósitos de carbono no eran importantes en el presupuesto de metano deglacial
M N Dyonisius1, V V Petrenko2, A M Smith3
1Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA. mdyonisi@ur.rochester.edu.
Science (New York, N.Y.)
|February 22, 2020
Resumen
Las emisiones de metano de las antiguas fuentes de carbono durante los eventos de calentamiento anteriores fueron mínimas. Esto sugiere que el calentamiento futuro puede no desencadenar grandes liberaciones de metano del permafrost e hidratos.
Área de la Ciencia:
- Ciencias del clima
- Paleoclimatología
- Geoquímica
Sus antecedentes:
- El permafrost y los hidratos de metano almacenan grandes cantidades de carbono viejo.
- El calentamiento de la Tierra plantea el riesgo de liberar metano, un potente gas de efecto invernadero.
- Los eventos de deglaciación pasados ofrecen información sobre la liberación de metano impulsada por el clima.
Objetivo del estudio:
- Para cuantificar las emisiones de metano de los antiguos depósitos de carbono durante la última deglaciación.
- Evaluar el potencial de grandes emisiones de metano por el permafrost y los hidratos en respuesta al calentamiento futuro.
- Estimar las emisiones de metano preindustriales procedentes de la quema de biomasa.
Principales métodos:
- Análisis de núcleos de hielo mediante mediciones isotópicas del metano (Δ14C, δ13C y δD).
- Reconstrucción de las fuentes y emisiones de metano durante la última deglaciación.
- Comparación de las emisiones deglaciales con los presupuestos de metano preindustriales y modernos.
Principales resultados:
- Las emisiones de metano de los antiguos depósitos de carbono durante el calentamiento deglacial fueron pequeñas (<19 Tg/año).
- La quema de biomasa contribuyó con 22-56 Tg / año de metano durante el Holoceno preindustrial, similar a los niveles actuales.
- Los resultados sugieren una liberación limitada de metano del permafrost e hidratos bajo el calentamiento pasado.
Conclusiones:
- El calentamiento pasado no indujo emisiones sustanciales de metano de antiguos depósitos de carbono.
- Es poco probable que las futuras emisiones de metano procedentes del permafrost y de los hidratos sean tan altas como se teme.
- La quema de biomasa fue una fuente significativa de metano en el Holoceno preindustrial.
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