The historically significant city of Alexandria, the birthplace of Cleopatra, is now facing the threat of disappearance. A new study reveals that due to climate change, which has caused rising sea levels, Alexandria is sinking. An international team of researchers reported that buildings in the 2,300-year-old port city are collapsing en masse. Scientists have warned that the city, once home to two wonders of the ancient world—the Great Library of Alexandria and the Lighthouse of Alexandria—is gradually vanishing. In just the last decade, the frequency of collapses has surged from one per year to a staggering 40, as saltwater increasingly seeps beneath the foundations. Over the past 20 years, coastal erosion has destroyed 280 structures, with another 7,000 at risk of collapse, according to the Daily Mail.
Sara Fouad, a landscape architect from the Technical University of Munich and the lead author of the study, noted, “For centuries, the structures of Alexandria were examples of resilient engineering, enduring earthquakes, storm surges, tsunamis, and much more. However, the rising sea levels and intensified storms caused by climate change have destroyed what took millennia to create.”
What did the scientists discover? Founded by Alexander the Great in 331 B.C., Alexandria was once the largest city on Earth and one of the most important places in the ancient world. Known as the “Bride of the Mediterranean,” its coastal location made it a vital hub for trade and shipping, connecting the Middle East and Europe. However, the very proximity to water that once fostered Alexandria’s growth now threatens to obliterate it.
As greenhouse gases accumulate in the atmosphere, the planet is warming, and ocean temperatures are rising. As water heats up, it expands, and combined with freshwater from rapidly melting glaciers, this raises sea levels. The authors of the new study combined satellite images with historical maps to assess how quickly the city’s coastline has been eroding since the 1880s. They found that in recent decades, Alexandria’s shoreline has shifted inland by dozens of meters, with some areas receding by as much as 3.6 meters each year.
“We are witnessing the gradual disappearance of historic coastal cities, and Alexandria is sounding the alarm. What once seemed like distant climate risks has now become a reality,” said co-author Dr. Essam Heggy from the University of Southern California. However, rising sea levels do not need to be drastic to have catastrophic consequences. Dr. Heggy pointed out, “Our research challenges the common misconception that we should only be concerned when sea levels rise by a meter.” Even a few centimeters of sea-level rise increases the risk of flooding and allows saltwater to penetrate deeper into coastal cities. It seeps beneath building foundations, undermining structures long before they come into direct contact with the sea.
Professor Ibrahim Saleh, a soil scientist from Alexandria University and a co-author of the study, reported, “Our isotopic analysis showed that buildings are collapsing from the bottom up, as seawater infiltration erodes foundations and weakens the soil.” The team is concerned that these threats are not unique to Alexandria; they affect coastal cities worldwide. To address these issues, researchers propose a range of potential solutions, such as constructing sand dunes along the coast, elevating buildings, or relocating people from the most vulnerable areas.
A recent NASA study indicated that some areas of California are sinking into the ocean faster than sea levels are rising. According to the National Oceanic and Atmospheric Administration (NOAA), global sea levels have risen by 20-23 centimeters since 1880, with 10 centimeters of that increase occurring just since 1993. A recent study from Nanyang Technological University (NTU) in Singapore predicted that global sea levels could rise by a staggering 1.9 meters by 2100 if carbon dioxide emissions continue to climb.