High sensitivity of the continental-weathering carbon dioxide sink to future climate change

• Published in: Nature climate change 2012-05, Vol.2 (5), p.346-349
• Main Authors: Beaulieu, E., Goddéris, Y., Donnadieu, Y., Labat, D., Roelandt, C.
• Format: Article
• Language: English
• Subjects: 704/106/35/824; 704/106/694; Anthropogenic factors; Atmospheric circulation; Carbon cycle; Carbon dioxide; Climate Change; Climate Change/Climate Change Impacts; Climatology; Earth and Environmental Science; Earth Sciences; Environment; Environmental Law/Policy/Ecojustice; Freshwater; Global temperatures; Global warming; Hydrologic cycle; Land use; letter; Ocean, Atmosphere; Oceanography; Paleontology; River basins; Sciences of the Universe; Vegetation cover; Weathering
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/nclimate1419

This modelling study shows that chemical weathering of continental surfaces—which removes carbon dioxide from the atmosphere—is highly sensitive to a carbon dioxide doubling for the Mackenzie River Basin, the most important Arctic watershed. The findings highlight the potential role of chemical weathering processes in mitigating global warming. According to future anthropogenic emission scenarios, the atmospheric CO 2 concentration may double before the end of the twenty-first century 1 . This increase is predicted to result in a global warming of more than 6 °C in the worst case 1 . The global temperature increase will promote changes in the hydrologic cycle through redistributions of rainfall patterns and continental vegetation cover 1 , 2 . All of these changes will impact the chemical weathering of continental rocks. Long considered an inert CO 2 consumption flux at the century timescale, recent works have demonstrated its potential high sensitivity to the ongoing climate and land-use changes 3 , 4 . Here we show that the CO 2 consumption flux related to weathering processes increases by more than 50% for an atmospheric CO 2 doubling for one of the most important Arctic watersheds: the Mackenzie River Basin. This result has been obtained using a process-based model of the chemical weathering of continental surfaces forced by models describing the atmospheric general circulation and the dynamic of the vegetation 5 , 6 under increased atmospheric CO 2 . Our study stresses the potential role that weathering may play in the evolution of the global carbon cycle over the next centuries.