New research  finds that a combination of extreme climate events, sea-level rise and land subsidence could create larger and deeper floods in coastal cities in future. 

The study focused on Shanghai in China, which is threatened with flooding by large and strong typhoons, or tropical storms, producing storm surges and waves. To avoid disaster a major adaptation effort is required - which will almost certainly include raising defences and constructing mobile flood barriers, like those seen at the Thames Barrier in London. However, the team warn there is also the risk of “catastrophic failure” of defences due to rising water levels, especially due to the combination of subsidence, sea-level rise and higher surges during typhoons, as occurred in New Orleans during Hurricane Katrina in 2005.  

Researchers at University of Tsukuba and the Meteorological Research Institute have identified how atmosphere-ocean interactions in the midlatitudes reinforce the East Asian winter monsoon (EAWM). During strong monsoon seasons, cold air outbreaks from the Eurasian continent cool the midlatitude western North Pacific (WNP). This oceanic cooling, in turn, alters atmospheric circulation in a manner that further intensifies the monsoon. The results underscore the importance of midlatitude feedback processes in driving winter climate variability over East Asia and provide insights that may improve the prediction of extreme weather events and enhance seasonal forecasting.