# Saltwater intrusion and human health risks for coastal populations under 2050 climate scenarios

## TL;DR

This paper explores how saltwater intrusion due to climate change by 2050 could impact human health, particularly in coastal regions.

## Contribution

The study introduces a novel vulnerability framework combining saltwater intrusion projections, population reliance on groundwater, and sodium excretion data.

## Key findings

- 41 countries are projected to experience saltwater intrusion of at least 1 km inland by 2050.
- Seven low- and middle-income countries in South/Southeast Asia are identified as highly vulnerable.
- The study highlights the need for localized geological research and community-driven solutions.

## Abstract

Populations consuming saline drinking water are at greater risk of high blood pressure and potentially other adverse health outcomes. We modelled data and used available datasets to identify countries of higher vulnerability to future saltwater intrusion associated with climate change in 2050 under Representative Concentration Pathways (RCP)4.5 and RCP8.5. We developed three vulnerability criteria to capture geographies with: (1) any coastal areas with projected inland saltwater intrusion of ≥ 1 km inland, (2) > 50% of the population in coastal secondary administrative areas with reliance on groundwater for drinking water, and 3) high national average sodium urinary excretion (i.e., > 3 g/day). We identified 41 nations across all continents (except Antarctica) with ≥ 1 km of inland saltwater intrusion by 2050. Seven low- and middle-income countries of higher vulnerability were all concentrated in South/Southeast Asia. Based on these initial findings, future research should study geological nuances at the local level in higher-risk areas and co-produce with local communities contextually appropriate solutions to secure equitable access to clean drinking water.