THE Big Apple could be awash by the end of this century. New predictions suggest that US east coast cities will be hit hard by sea level rise.
Today, the sea level along the US east coast is relatively low, whereas further offshore it rises sharply. This anomaly is caused by the balance of forces required for the flow of the Gulf Stream and North Atlantic Current, both of which contribute to the Atlantic meridional overturning circulation (AMOC).
The AMOC transports warm surface waters to polar latitudes, where it cools and sinks before flowing back south. A previous study has shown that the AMOC slowed by about 30 per cent between 1957 and 2004 (快猫短视频, 3 December 2005, p 6), and it is expected to slow further due to global warming.
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Jianjun Yin of Florida State University in Tallahassee and colleagues used climate models to study how an AMOC slowdown would affect sea levels. They found that, for the worst-case scenario of greenhouse gas emissions, the sea level rise due to AMOC slowdown on top of the thermal expansion of water could reach 52, 51 and 44 centimetres around Boston, New York and Washington DC respectively by 2100. This would pose a particular threat to New York, as some parts are only 1.5 metres above sea level (Nature Geoscience, DOI: ).
鈥淭he modelling is highly credible,鈥� says Stuart Cunningham at the National Oceanography Centre in Southampton, UK.