From London and Rotterdam to Egypt’s Alexandria, most of the world’s great old cities were settled in river deltas. Because of the ease of shipping heavy loads by water in ancient times, river deltas developed as trading posts, and grew over the centuries from villages to become the major population centers. Even in recent centuries, newer cities like Hong Kong and New York followed the pattern. But as a result, two thirds of the largest cities in the world are located in delta areas and coastal zones – that will be directly impacted as sea levels rise.
In Egypt, the rising sea level is already affecting Alexandria’s drinking water supplies and sewage systems that depend on water running downhill to the sea.
“Blockages occur every day,” a local female resident of Alexandria told Al Masry Al Youm. “Water pressure is low and most of the time it goes away completely, forcing us to fetch water from the river and bring it back home in bottles.”
Tourism is also affected. Beaches are a big draw for Egypt’s tourist trade.
Mohamed El Raey, professor of Environmental Studies at the University of Alexandria, described how the rise in sea level is expected to drastically disturb tourism in Egypt.
“In the summertime, the beach is completely covered with people, you can’t see one free spot of sand,” he says. “But if the water continues to rise the people are going to desert the beaches. That’s why we are putting a constant pressure on the decision-makers to expand Alexandria to higher level areas before it’s too late.”
Last year, even under the former regime, the Egyptian government was already considering adaptation. After seawater incursions reached as far as the city of Rosetta, Kafr al-Sheik Governor Ahmed Zaki Abdin told Al Masry Al Youm that the International Highway along the North Coast is expected to be threatened with collapse even with sea level rise of just another 10 cm. He proposed a plan to erect concrete sea walls between Lake Borollos and the village of Metobas.
This week, Cairo University screened a documentary on the issue of seawater rise affecting Delta cities, as part of the Wadi Environmental Sciences Center film series.
“Connecting Delta Cities” gathers interviews from experts and residents in different delta cities worldwide dealing with the problem, which manifests differently in each circumstance. New York, for example has no worries from loss of tourism on beaches, but its subways are highly susceptible to flooding in storm surges, as the frequency and intensity increases.
Nobody can predict how fast the world will move over the next few decades to effectively lower the greenhouse gases that are causing the rising levels of CO2 that are warming the planet, so scientists cannot be specific about predictions of resulting sea level rise. A wide range of effects predicted thus depend on what actions will be taken by both current and future governments.
Even future unplanned events like global recessions will have an effect on greenhouse gases as well. But how many global recessions there will be over the next decades and centuries is not known by climate scientists, either. They can forecast only the physics. If you add X amount of CO2 to the atmosphere, you’ll get Y amount of warming, which results in Z amount of sea level rise (among many other effects.)
But increasingly, as we have narrowed our choices through several decades of government inaction, we can rule out the most benign predictions. Now, scientists say, that while the exact rise in sea levels by 2100 is not predictable, global average sea level rise is now unlikely to be below one and a half metres by 2100. And it could be much worse.
Image: EastMar Tours