Bilal U. Haq*
Sorbonne University, Paris, France, 75006; Smithsonian Institution, Washington, D.C., 20024, USA
John D. Milliman
William & Mary, Williamsburg, Virginia 23185, USA
Abstract
River deltas occupy only ~0.65% of Earth’s land surface, but collectively house ~4.5% of the global
population and account for more than 6% of the global GDP. Because of ongoing human interventions in the
past century (river diversions, groundwater and petroleum extraction, and urbanization), deltas are coming
under additional and intense threat from climate change and the impending sea-level rise. Many high-latitude
and tropical deltas where population pressure is low and human modification is minimal face less peril for
the foreseeable future, but densely populated deltas, especially those in Asia with extreme urbanization and
environmental pressures, will be more susceptible to land loss and drowning. Here we consider six key
deltas—Mississippi, Yangtze, Niger, Bengal, Nile, and Indus—emphasizing recent findings and consensus as to
their health and how human activities have brought these vulnerable ecosystems perilously close to or beyond
the point of no return.
*bilhaq@gmail.com
CITATION: Haq, B.U., and Milliman, J.D., 2023, Perilous future for river deltas: GSA Today, v. 33, p. 4–12,
https://doi.org/10.1130/GSATG566A.1. © 2023 The Authors. Gold Open Access:
This paper is published under the terms of the CC-BY-NC license. Printed in the USA.
Manuscript received 6 Mar. 2023. Revised manuscript received 30 May 2023.
Manuscript accepted 26 July 2023. Posted 7 Sept. 2023.
© The Geological Society of America, 2023. CC-BY-NC.
https://doi.org/10.1130/GSATG566A.1