Publication Date:
2015-10-05
Description:
Following large explosive volcanic eruptions, precipitation decreases over much of the globe, particularly in climatologically wet regions. Stratospheric volcanic aerosols reflect sunlight, which reduces evaporation, whilst surface cooling stabilizes the atmosphere and reduces its water-holding capacity. Circulation changes modulate this global precipitation reduction on regional scales. Despite the importance of rivers to people, it has been unclear whether volcanism causes detectable changes in streamflow, given large natural variability. Here we analyse observational records of streamflow volume for fifty large rivers from around the world that cover between two and six major volcanic eruptions in the twentieth and late nineteenth century. We find statistically significant reductions in flow following eruptions for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma, amongst others. When data from neighbouring rivers are combined - based on the areas where climate models simulate either an increase or a decrease in precipitation following eruptions - a significant (p 〈 0.1) decrease in streamflow following eruptions is detected in northern South American, central African and high-latitude Asian rivers, and on average across wet tropical and subtropical regions. We also detect a significant increase in flow in southern South American and southwestern North American rivers. Our findings suggest that future volcanic eruptions could substantially affect global water availability. © 2015 Macmillan Publishers Limited.
Print ISSN:
1752-0894
Electronic ISSN:
1752-0908
Topics:
Geosciences
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