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Un cortocircuito en la circulación termohalina: ¿Una causa de la glaciación del hemisferio norte?
1N. W. Driscoll, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. G. H. Haug, GEOMAR, Forschungszentrum fur Marine Geowissenschaften, Universitat Kiel, Wischhofstrasse 1-3, D-24148 Kiel, Germany.
Science (New York, N.Y.)
|October 17, 1998
Resumen
La causa de la glaciación del hemisferio norte sigue siendo incierta. El suministro mejorado de agua dulce del río siberiano al Ártico puede haber promovido la formación de hielo al aumentar el albedo y reducir el transporte de calor oceánico.
Área de la Ciencia:
- Ciencias de la Tierra Ciencias de la Tierra Ciencias de la Tierra
- Paleoclimatología Paleoclimatología
- Oceanografía La oceanografía es la oceanografía.
Sus antecedentes:
- La transición Plioceno-Pleistoceno (hace aproximadamente 3 millones de años) vio el inicio de la glaciación del hemisferio norte, un cambio climático importante.
- El cierre del istmo panameño es un motor propuesto, que mejora la circulación oceánica y la humedad en latitudes altas, pero potencialmente inhibe el crecimiento del hielo debido al aumento del transporte de calor.
Objetivo del estudio:
- Investigar un mecanismo potencial para la glaciación del hemisferio norte que concilia los efectos del aumento de la humedad y el transporte de calor.
Principales métodos:
- Este estudio propone una hipótesis basada en los modelos paleoceanográficos y climáticos existentes.
- Se centra en el papel de la descarga de agua dulce en el Océano Ártico.
Principales resultados:
- Un mejor transporte de humedad a Eurasia a través de una circulación atmosférica intensificada podría aumentar la descarga de agua dulce al Océano Ártico a través de los ríos siberianos.
- Esta afluencia de agua dulce puede promover la formación de hielo marino, aumentando así el albedo planetario.
- El aumento de la cubierta de hielo marino aislaría el océano, reduciendo la transferencia de calor a la atmósfera y contrarrestando los efectos del calentamiento.
Conclusiones:
- La entrega de agua dulce al Ártico a través de los ríos siberianos ofrece un mecanismo plausible para iniciar la glaciación del hemisferio norte.
- Este proceso implica un ciclo de retroalimentación negativa donde el aumento de la cubierta de hielo reduce el intercambio de calor océano-atmósfera, lo que facilita un mayor enfriamiento y crecimiento del hielo.
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