Scientists warn of sea level tsunami threat

A sea level rise of just half a metre (1.6ft) could dramatically increase the risk of devastating tsunamis, research has shown.

As sea levels rise due to global warming, smaller earthquakes that currently pose no serious tsunami threat could unleash waves capable of inundating coastal cities, scientists found.

The study focused on Macau, the densely populated former Portuguese colony and gambling centre situated on China’s southern coast.

Currently the Chinese autonomous territory is considered safe from tsunamis, despite lying within a major earthquake zone.

At today’s sea level, it would take a very powerful earth- quake tipping past magnitude 8.8 to cause widespread tsunami flooding in Macau.

But a half-metre rise in sea level – predicted to occur in the region by 2060 – could more than double the chances of a huge tsunami swamping the territory, according to the research.

A three-foot sea level rise, expected by 2100, would increase the risk up to 4.7 times.

The source of the earthquake danger is the Manila Trench, a massive crack in the floor of the South China Sea formed by the collision of two tectonic plates.

It has generated numerous earthquakes, though none larger than magnitude 7.8 since the 1560s. A modest rise in sea levels would greatly amplify the tsunami threat from smaller earthquakes.