Abstract
In recent years, increased salt intrusion in surface waters has threatened freshwater availability in coastal regions worldwide. Yet, current future projections of salt intrusion are limited to local regions or changes to single forcing agents. Here, we quantify compounding contributions from changes in river discharge and relative sea level to changing future salt intrusion under a high-emission scenario (Shared Socioeconomic Pathway, SSP3-7.0) for 18 estuaries around the world. We find that the annual 90th percentile future salt intrusion is projected to increase between 1.3% and 18.2% (median 9.1%) in 89% of the studied estuaries worldwide. Our analysis also indicates that, on average, sea-level rise contributes approximately two times more to increasing future salt intrusion than reduced river discharge. We further show that the return levels of present-day 100-year salt intrusion events are projected to increase between 3.2% and 25.2% (median 10.2%) in 83% of the studied estuaries.
| Original language | English |
|---|---|
| Article number | 3444 |
| Journal | Nature Communications |
| Volume | 16 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2025 |
Funding
This work is financially supported by NWO Domain Applied and Engineering Sciences (2022/TTW/01344701, Perspective Program SALTISolutions, H.A.D.) and Deltares’s strategic research initiative -Liveable Deltas in a Changing World’ (11209189-029, Salt Intrusion around the World under influence of Climate Change, W.K.). The authors appreciate Dutch National Supercomputer (Snellius) for the computational resources. The authors are also grateful to Dr. Tim Hermans for his valuable insight on the analysis of vertical land motion and Avelon Gerritsma for her exploratory activities in the inception phase of the project.