# Global coastal exposure patterns by coastal type from 1950 to 2050

## TL;DR

This study maps global coastal environments and predicts how rising sea levels and population growth will increase flood exposure in different regions from 1950 to 2050.

## Contribution

The study introduces a detailed global mapping of seven coastal environments and their exposure to flooding, considering population growth and sea-level rise.

## Key findings

- Low-lying deltaic and estuarine areas have historically housed over 48% of the coastal population.
- Barrier islands and strandplains will see over 40% increased flood exposure by 2050, especially in Africa.
- Population growth is the main driver of increased flood exposure, with sea-level rise contributing 26-65% of increased inundation.

## Abstract

Addressing sea-level rise and coastal flooding requires adaptation strategies tailored to specific coastal environments. However, a lack of detailed geomorphological data on global coasts impedes effective strategy development. This research maps seven coastal environments worldwide, and for each environment analyzes the effect of coastal changes on coastal populations by including sea-level change, extreme sea-level events with varying return periods and population growth from 1950 to 2050. It identifies the historical exposure of low-lying deltaic and estuarine flood areas (>48% of total population) and reveals that flood exposure will significantly increase for barrier islands and strandplains by 2050 (with over a 40% rise in exposure), particularly along African coastlines. Population growth emerges as the primary factor behind the increased exposure. While sea-level rise is projected to contribute between 26% and 65% of the increased inundated area by 2050 compared to a 10-year extreme sea-level event, varying by coastal environment. The findings highlight the critical need for mitigation measures that account for the distinct responses of different coastal types to sea-level rise, posing various risks over varying timescales.