Carbon emissions along divergent plate boundaries modulate icehouse-greenhouse climates

[Geoengineering News]

https://www.nature.com/articles/s43247-025-03097-0

Authors: Ben R. Mather, R. Dietmar Müller, Adriana Dutkiewicz & Sabin Zahirovic 

19 January 2026

Abstract

The exchange of carbon between oceanic plates, the deep Earth, and the atmosphere plays a significant role in modulating global climate. Icehouse-greenhouse climate fluctuations have been attributed to changes in palaeogeography and solid Earth degassing, particularly along continental arcs, to arc weathering and to the sequestration of carbon into oceanic carbonate-rich sediments. However, the proportions of these contributions and their effect on modulating global climate are poorly constrained. Here we show that the changing balance between volcanic outgassing and carbon sequestration into oceanic lithosphere is the key driver for major climate shifts. Combined volcanic arc, mid-ocean ridge and continental rift emissions exceed carbon sequestration during greenhouse climates. In contrast, oceanic plate sequestration exceeds emissions during icehouse climates. Our results challenge the long-held view that carbon degassing along volcanic arcs is the main contributor to atmospheric carbon, suggesting instead that mid-ocean ridge and rift degassing surpass arc emissions before 100 Ma.

Source: Communications Earth & Environment