Ho Chi Minh City in Vietnam is increasingly vulnerable to flooding because of rising sea levelsGetty Images
There has been an abrupt change in the rate of sea level rise as measured by satellites. Around 2012, it suddenly accelerated and has remained higher ever since.
It is possible that the sudden jump is mainly due to natural variation. However, it could also be a response to the accelerating rate of global warming, says Lancelot Leclercq at the University of Toulouse in France.
The average global sea level has already risen by more than 0.2 metres over the past 15 years as a result of global warming. This has been caused by a number of factors: as well as increasing melting of mountain glaciers and the ice sheets of Greenland and Antarctica, the oceans are expanding as they warm.
Satellite measurements of sea level began only in the 1990s and the rate of rise was thought to have been fairly steady, at around 3.6 millimetres per year. But, as more satellite data has come in, Leclercq’s team has spotted a sudden step change around 2012, with the average rate jumping from 2.9 mm/year before 2012 to 4.1 mm/year since then.
