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Projections of declining fluvial sediment delivery to major deltas worldwide in response to climate change and anthropogenic stress

Projections of declining fluvial sediment delivery to major deltas worldwide in response to climate change and anthropogenic stress
Projections of declining fluvial sediment delivery to major deltas worldwide in response to climate change and anthropogenic stress
Deltas are resource rich, low-lying areas where vulnerability to flooding is exacerbated by natural and anthropogenically induced subsidence and geocentric sea-level rise, threatening the large populations often found in these settings. Delta 'drowning' is potentially offset by deposition of sediment on the delta surface, making the delivery of fluvial sediment to the delta a key balancing control in offsetting relative sea-level rise, provided that sediment can be dispersed across the subaerial delta. Here we analyse projected changes in fluvial sediment flux over the 21st century to 47 of the world's major deltas under 12 environmental change scenarios. The 12 scenarios were constructed using four climate pathways (Representative Concentration Pathways 2.6, 4.5, 6.0 and 8.5), three socioeconomic pathways (Shared Socioeconomic Pathways 1, 2 and 3), and one reservoir construction timeline. A majority (33/47) of the investigated deltas are projected to experience reductions in sediment flux by the end of the century, when considering the average of the scenarios, with mean and maximum declines of 38% and 83%, respectively, between 1990–2019 and 2070–2099. These declines are driven by the effects of anthropogenic activities (changing land management practices and dam construction) overwhelming the effects of future climate change. The results frame the extent and magnitude of future sustainability of major global deltas. They highlight the consequences of direct (e.g. damming) and indirect (e.g. climate change) alteration of fluvial sediment flux dynamics and stress the need for further in-depth analysis for individual deltas to aid in developing appropriate management measures.
1748-9326
1-11
Dunn, Frances
43ad074b-3134-4fc9-8c42-b330ee590f98
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Nicholls, Robert
4ce1e355-cc5d-4702-8124-820932c57076
Cohen, Sagy
99521dde-cd3d-46ff-8cba-3c1fca9e73d4
Zarfl, Christiane
f3e76e7d-c154-4fb8-bd38-7165519a2cb9
Fekete, Balazs
7a6419d5-4552-4c4f-842b-5188926a769f
Dunn, Frances
43ad074b-3134-4fc9-8c42-b330ee590f98
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Nicholls, Robert
4ce1e355-cc5d-4702-8124-820932c57076
Cohen, Sagy
99521dde-cd3d-46ff-8cba-3c1fca9e73d4
Zarfl, Christiane
f3e76e7d-c154-4fb8-bd38-7165519a2cb9
Fekete, Balazs
7a6419d5-4552-4c4f-842b-5188926a769f

Dunn, Frances, Darby, Stephen, Nicholls, Robert, Cohen, Sagy, Zarfl, Christiane and Fekete, Balazs (2019) Projections of declining fluvial sediment delivery to major deltas worldwide in response to climate change and anthropogenic stress. Environmental Research Letters, 14, 1-11. (doi:10.1088/1748-9326/ab304e).

Record type: Article

Abstract

Deltas are resource rich, low-lying areas where vulnerability to flooding is exacerbated by natural and anthropogenically induced subsidence and geocentric sea-level rise, threatening the large populations often found in these settings. Delta 'drowning' is potentially offset by deposition of sediment on the delta surface, making the delivery of fluvial sediment to the delta a key balancing control in offsetting relative sea-level rise, provided that sediment can be dispersed across the subaerial delta. Here we analyse projected changes in fluvial sediment flux over the 21st century to 47 of the world's major deltas under 12 environmental change scenarios. The 12 scenarios were constructed using four climate pathways (Representative Concentration Pathways 2.6, 4.5, 6.0 and 8.5), three socioeconomic pathways (Shared Socioeconomic Pathways 1, 2 and 3), and one reservoir construction timeline. A majority (33/47) of the investigated deltas are projected to experience reductions in sediment flux by the end of the century, when considering the average of the scenarios, with mean and maximum declines of 38% and 83%, respectively, between 1990–2019 and 2070–2099. These declines are driven by the effects of anthropogenic activities (changing land management practices and dam construction) overwhelming the effects of future climate change. The results frame the extent and magnitude of future sustainability of major global deltas. They highlight the consequences of direct (e.g. damming) and indirect (e.g. climate change) alteration of fluvial sediment flux dynamics and stress the need for further in-depth analysis for individual deltas to aid in developing appropriate management measures.

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Accepted/In Press date: 4 July 2019
Published date: 6 August 2019

Identifiers

Local EPrints ID: 433419
URI: https://eprints.soton.ac.uk/id/eprint/433419
ISSN: 1748-9326
PURE UUID: 006f0c24-3d78-4ece-9e02-8e93bb5a72ad
ORCID for Frances Dunn: ORCID iD orcid.org/0000-0003-3726-7158
ORCID for Stephen Darby: ORCID iD orcid.org/0000-0001-8778-4394
ORCID for Robert Nicholls: ORCID iD orcid.org/0000-0002-9715-1109

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Date deposited: 21 Aug 2019 16:30
Last modified: 22 Aug 2019 00:36

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Contributors

Author: Frances Dunn ORCID iD
Author: Stephen Darby ORCID iD
Author: Robert Nicholls ORCID iD
Author: Sagy Cohen
Author: Christiane Zarfl
Author: Balazs Fekete

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