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El nivel medio global del mar en los últimos 4,5 millones de años
Peter U Clark1,2, Jeremy D Shakun3, Yair Rosenthal4,5
1College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
Science (New York, N.Y.)
|October 16, 2025
Resumen
El nivel global del mar fluctuó significativamente en el Cenozoico tardío. La glaciación del hemisferio norte comenzó hace unos 4 millones de años, con capas de hielo intensificadas durante el Pleistoceno.
Área de la Ciencia:
- Paleoceanografía
- Ciencias del clima
- Geología
Sus antecedentes:
- Los cambios en el nivel medio global del mar (GMSL) en el Cenozoico tardío no se comprenden bien.
- La reconstrucción del nivel del mar pasado es crucial para comprender la dinámica climática y el comportamiento de las capas de hielo.
Objetivo del estudio:
- Para reconstruir los cambios de GMSL desde hace 4.5 millones de años (Ma) hasta el presente.
- Investigar el inicio y la intensificación de la glaciación en el hemisferio norte.
- Para entender los impulsores de la variabilidad de las capas de hielo durante el Pleistoceno.
Principales métodos:
- Utilizó una nueva reconstrucción del agua de mar δ 18 O.
- Contabilizó los cambios impulsados por la temperatura en las capas de hielo globales.
- Cambios correlacionados del nivel del mar con forzamientos paleoclimáticos como la oblicuidad y la variabilidad de CO2.
Principales resultados:
- El nivel del mar se elevó hasta 20 m por encima del actual entre 4,5 y 3 Ma.
- Los primeros puntos bajos del nivel del mar por debajo del presente indican el inicio de la glaciación en el hemisferio norte a 4 Ma.
- La glaciación intensificada de 3 a 2.5 Ma condujo a niveles bajos similares al Último Máximo Glacial durante todo el Pleistoceno.
- La transición del Pleistoceno medio en la variabilidad de las capas de hielo se relacionó con la variabilidad de CO2 que modulaba la oblicuidad.
Conclusiones:
- El Cenozoico tardío experimentó fluctuaciones significativas de GMSL impulsadas por la dinámica de las capas de hielo.
- La glaciación del hemisferio norte y la subsecuente intensificación impactaron profundamente los niveles globales del mar.
- La variabilidad del CO2 jugó un papel clave en la modulación del comportamiento de las capas de hielo durante el Pleistoceno.
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