New York City is sinking by up to four millimetres a year because of its skyscrapers. Its 1,080,000 buildings weigh around 764 billion kilograms. There is additional weight from furniture, transport infrastructure, and the city's 8.5 million people. Dr Tom Parsons said the slow sinking plus rising sea levels could mean New York has more natural disasters. New buildings could increase flooding especially along coasts.

Researchers compared New York to Venice and Jakarta. Venice is flooding more despite a new $5.3 billion system of sea walls. Indonesia is building a new capital because Jakarta is sinking. The UN forecast that 70 per cent of the world will live in cities by 2050. Dr Parsons said when a city gets full of people, "you end up with subsidence." He said New York was typical of a place where many people move to.