Getting your Trinity Audio player ready...
Coastal erosion along the shores of ancient Alexandria has accelerated over the past decade, leading to the collapse of hundreds of buildings in Egypt’s historic Mediterranean port city, a new study has found.
According to research published in the journal Earth’s Future, at least 280 structures have collapsed due to coastal degradation in the past two decades, and roughly 7,000 more buildings are at risk. Alexandria, once home to the famed Library of Alexandria and the birthplace of Cleopatra, is experiencing severe shoreline retreat, driven by rising sea levels and intensifying storms linked to climate change.
“This is not just about bricks and mortar. We are witnessing the gradual disappearance of one of the world’s most historically significant coastal cities,” said Dr. Essam Heggy, a co-author of the study from the University of Southern California’s Viterbi School of Engineering. “What once seemed like distant climate threats are happening before our eyes.”
Dr. Sarah Fouad, a landscape architect at the Technical University of Munich and a member of the research team, said, “Rising sea levels and worsening storms—fueled by climate change—are undoing in decades what human ingenuity built over millennia.”
A city under threat
The collapse of Alexandria’s coastal buildings is caused by seawater intrusion, which raises groundwater levels and weakens building foundations. The saltwater accelerates the deterioration of structural materials, further undermining stability.
3 View gallery
The significant changes that occurred in the coastline of Alexandria between 1935 and 2022
(Photo: Essam Heggy, Sara Fouad)
The findings align with warnings from NASA and the U.S. National Oceanic and Atmospheric Administration (NOAA), which report that global sea levels have risen by an average of 20 to 23 centimeters (8 to 9 inches) since 1880, including a 10-centimeter (4-inch) rise since 1993. Low-lying coastal cities and small island nations face the highest risk of land erosion and flooding.
Get the Ynetnews app on your smartphone: Google Play: https://bit.ly/4eJ37pE | Apple App Store: https://bit.ly/3ZL7iNv
“What we’re seeing in Alexandria is a nightmare scenario playing out for coastlines worldwide, especially in the Mediterranean,” Heggy said.
Mapping the damage
To assess the extent of destruction, researchers created a detailed digital map using geographic information system (GIS) technology, pinpointing the locations of collapsed buildings and analyzing their structural attributes, such as age, materials, foundation depth, and number of floors. Data was gathered from site visits, government reports, news archives, and private construction firms, covering full and partial collapses from 2001 to 2021.
3 View gallery
The consequences of sea level rise on the Alexandria coastline
(Photo: Earth's Future)
The team also combined satellite imagery with historical maps from 1887, 1959, and 2001 to track shoreline changes. The analysis confirmed that the rise in groundwater levels—resulting from seawater intrusion—has destabilized building foundations. To further investigate, researchers conducted isotope analysis on soil samples, identifying chemical “fingerprints” that revealed whether land was stable or at risk of erosion.
“Our isotope analysis showed that buildings are collapsing from the bottom up as seawater erodes their foundations,” said study co-author Prof. Ibrahim Saleh of Alexandria University.
The researchers outlined several measures to protect Alexandria from further destruction, including constructing sand dunes and seawalls, elevating buildings, and relocating residents in high-risk areas.
“Historic cities like Alexandria, which have been centers of cultural exchange, innovation, and history, are crucial to preserving our shared human heritage,” Heggy said. “As climate change accelerates sea-level rise and coastal erosion, protecting them is not just about saving buildings—it’s about preserving who we are.”