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Tendencias en la amplitud estacional del metano atmosférico

Gang Liu¹, Lu Shen², Philippe Ciais³

¹Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, and Laboratory for Earth Surface Processes, Peking University, Beijing, China.

|May 7, 2025

Resumen

Los cambios en la amplitud del ciclo estacional (SCA) del metano revelan la retroalimentación climática. Las altas latitudes del norte muestran una disminución del SCA debido al aumento de las emisiones naturales, mientras que los trópicos muestran un aumento del SCA debido a una oxidación más fuerte.

Área de la Ciencia:

Química atmosférica y ciencias del clima
Dinámica de los gases de efecto invernadero
Ciencias del sistema terrestre

Sus antecedentes:

El metano es un potente gas de efecto invernadero con concentraciones preindustriales triplicadas.
Las tendencias de la amplitud del ciclo estacional (SCA) en el metano muestran divergencias regionales: disminución en las altas latitudes del norte y aumento en los trópicos y subtrópicos desde la década de 1980.
La comprensión de estas tendencias es crucial para descifrar los cambios a largo plazo en el presupuesto mundial de metano.

Objetivo del estudio:

Investigar y atribuir las tendencias observadas en la amplitud del ciclo estacional del metano (SCA).
Para diferenciar los impactos de los cambios en las emisiones frente a los cambios en el sumidero atmosférico en el SCA de metano.
Proporcionar pruebas independientes de los cambios en la concentración atmosférica de radicales hidroxilo (OH).

Principales métodos:

Utilizó un conjunto de simulaciones de transporte atmosférico.
Tendencias analizadas en la amplitud del ciclo estacional del metano (SCA).
Tendencias de SCA atribuidas a factores específicos: emisiones naturales y oxidación del radical hidroxilo (OH).

Principales resultados:

La disminución del SCA en las latitudes altas del norte se debe principalmente al aumento de las emisiones naturales (por ejemplo, los humedales) vinculadas a un clima más cálido, lo que respalda una retroalimentación climática positiva.
El aumento del metano SCA en los trópicos y subtrópicos se atribuye principalmente al fortalecimiento de la oxidación de OH.
La evidencia independiente indica un aumento de 10 ± 1% en la concentración de OH en la troposfera desde 1984.

Conclusiones:

El estudio confirma un ciclo de retroalimentación climática positivo que influye en las emisiones de metano en las latitudes altas del norte.
El fortalecimiento de la oxidación de OH en los trópicos y subtrópicos ha impactado significativamente el sumidero atmosférico de metano.
Se estima un aumento del 21 ± 1% en el sumidero de metano atmosférico, impulsado por el aumento de las concentraciones de OH y los niveles de metano.

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