Coastal hardening and what it means for the world's sandy beaches.

Sea level rise is expected to cause chronic shoreline retreat, affecting over 10% of the world's population in low-elevation coastal zones (LECZ). Sandy beaches supported by man-made structures are more vulnerable to substantial beach area loss due to restricted landward migration, affecting ecosystem services. However, the global extent of 'hardened' sandy coastlines at risk of 'severe beach loss' has not been comprehensively quantified.