Populous coastal regions around the world are sinking four times faster than global average amid rising sea level, a new study released on Monday said.
Groundwater pumping, extraction of materials from the ground and sediment production are all happening near the coasts and that is causing the land to actually sink.
Many of the largest, most populated cities in the world are built along the deltas of major rivers, where there is the added exposure of rivers connecting to the ocean.
Much of the coast is uninhabited by people, but where there is civilization, there tends to be a greater rise in water levels.
According to the study, it quantifies “global-mean relative sea-level rise to be 2.5 mm per year over the past two decades. However, as coastal inhabitants are preferentially located in subsiding locations, they experience an average relative sea-level rise up to four times faster at 7.8 to 9.9 mm per year.”
The study found that one in five people live along the coastline where the sea level is increasing at 10 mm.
Until now scientists were only aware of pollution linking climate change to sea level rise, but this study talks deep about how land patterns use are affecting sea level rise.
Asia most impacted
Coastal sections of Asia have been the most impacted by sea level rise in relation to land subsidence. That’s because there is a prevalence of deltas and very populous cities.
“South, Southeast and East Asia is noteworthy, as these regions collectively contain 71% of the global coastal population below 10 m in elevation,” according to the research.
“In Jakarta, subsidences of over 10 centimeters per year — It may be even locally faster than that. You can get very, very large changes, but in very small areas,” Robert Nicholls, lead author of this research and director of the UK’s Tyndall Centre for Climate Change Research said. “But they’re important because lots of people live there.”
When asked what can be done about this issue, Nicholls said mitigating the threats of climate change is most crucial.
“I think the important thing is we have a great effort, and rightly so, to actually mitigating climate change and the Paris Agreement,” Nicholls said.
The report also says reducing groundwater withdrawal and managing deltas can reduce land subsidence.