Climate change will bring good news and really bad news for New York City. The good news is that hurricanes might be more likely to miss the city over the next three centuries. This means the future risk of big storm surges, relative to local sea level, could be lower than today. However, the really bad news is that if we don’t slash greenhouse gas emissions, local sea level will rise by a huge 13 metres or more. With this factored in, New York could be facing storm surges at least 15 metres above the current sea level by 2300 (PNAS, doi.org/cfgw).

“Sea level rise itself is a very big hazard, before you start to look at tropical cyclones,” says Andra Garner of Rutgers University in New Jersey.Garner’s team used climate models to simulate the paths of future hurricanes and the storm surges they will produce. These were combined with estimates of sea level rise.They conclude that 2.3-metre floods, which happened in New York on average once in 500 years before 1800, struck roughly every 25 years from 1970 to 2005, will probably hit every five years by 2030 to 2045.If we don’t cut emissions, local sea level could permanently rise by 2.3 metres before the century ends.What’s more, meteorologist Jeff Masters of Weather Underground says the good news part could be wrong: at least one study shows climate change will make hurricanes more likely to hit the north-east US.
This article appeared in print under the headline “Future New York will be flooded”
(New Scientist)

It’s worth remembering that two-thirds of the world’s cities sit on coastlines. A rise in global sea levels of 11 feet would fully submerge cities like Mumbai and a large part of Bangladesh.