One of the world’s top tourist destinations — New York City — is sinking under the weight of its tall buildings. A new study looking at measurements from satellites in space and analysing layers of the Earth has found the weight of New York’s skyscrapers is proving too much for the soil beneath them to handle.
Soft layers of ground called sediments are shifting under the massive load, pushing them down and outwards. The city has one million buildings housing eight million people, which weigh a combined 764 billion kilograms. This load is causing the city to sink at up to 2mm each year.
And while 2mm may not sound like much, parts of the suburb of Lower Manhattan stand just 1m above sea level. At the current rate, king tides may be rolling seawater down its streets within a few decades.
“Every additional high-rise building constructed at coastal, river, or lakefront settings could contribute to future flood risk,” US Geological Survey geologist Tom Parsons warned. Parsons and his research team have mapped the city’s weight distribution on a 100-by-100m grid. This doesn’t include the weight of asphalt roads, brick bridges or concrete pavements. This was then overlaid on maps showing the sand, silt, clay, and bedrock sitting beneath.
He said the many buildings sitting on clay-rich soils and land filled in by man were most at risk. The researcher’s said New York was just one example of many coastal cities across the world sinking from a mix of rising sea levels, global warming, heavy buildings and pumping too much water from below ground to drink or stop flooding. The World Economic Forum lists the following cities among those at risk of disappearing by the year 2100.
Jakarta, Indonesia is sinking up to 17cm each year. The government plans to move the capital from the island of Java to Borneo to protect its 10 million residents from more flooding. The move would take about 10 years and cost $33 billion.
Lagos, Nigeria: Lagos’ low coastline continues to disappear, and rising seas caused by global warming put Africa’s largest city in danger of flooding.
Dhaka, Bangladesh: Oceans could flood 17 per cent of Bangladesh’s land and force about 18 million of its citizens to flee by 2050.
Venice, Italy: Italy has been building a $6.5 billion flood barrier known as Mose for 20 years. It will be fully working to stop flooding in 2025. The city is sinking by 2cm each year.
Bangkok, Thailand: It is sinking 1cm a year and could be below sea level by 2030. A huge 11-acre park that can hold 3.7 million litres of rainwater has been built to help stop flooding.
New Orleans, US: Some parts of the city are 4.5m below sea level, and its location where a river meets the sea increases its risk to rising sea-levels and flooding.
Rotterdam, The Netherlands: 90 per cent of Rotterdam is below sea level. The Dutch have built water parks that double as reservoirs* to capture floodwaters and barriers to stop storm swells.
Alexandria, Egypt: The city’s beaches are disappearing as the Mediterranean Ocean continues to rise.
