A global analysis of how human infrastructure squeezes sandy coasts

Area of Science:

• Coastal Ecology
• Environmental Science
• Marine Biology

Background:

• Coastal ecosystems offer essential services but face significant threats from human activities.
• Rising sea levels and coastal infrastructure development create a 'squeeze' on remaining natural habitats.
• Coastal congestion by infrastructure is a critical, yet unquantified, threat.

Purpose of the Study:

• To quantify the extent of coastal infrastructure congestion worldwide.
• To assess the impact of rising sea levels on remaining undeveloped shoreline space.
• To evaluate the effectiveness of nature reserves in mitigating coastal squeeze.

Main Methods:

• Analysis of 235,469 global transects to measure infrastructure proximity to sandy shorelines.
• Modeling future loss of undeveloped shoreline space due to sea-level rise by 2100.
• Statistical analysis correlating population density and GDP with coastal squeeze, and assessing nature reserve impact.

Main Results:

• Median infrastructure distance from sandy shorelines is 392 meters.
• 33% of sandy shores have <100m of undeveloped space, with 23-30% potentially lost by 2100.
• Population density and GDP explain 35-39% of squeeze variation; nature reserves reduce squeeze 4-7 times.

Conclusions:

• Coastal infrastructure poses a significant threat to sandy shorelines globally.
• Sea-level rise will exacerbate the loss of undeveloped coastal space.
• Integrating nature protection into spatial planning is crucial, as only 16% of sandy shores are currently protected.