Massive floods are taking place in coastal areas across the globe, which scientists explain as to due rising sea levels in combination with land subsidence.
According to a report released by the Intergovernmental Panel on Climate Change (IPCC), sea levels in coastal areas have been rising at a rate that is four times faster than the worldwide average. Areas with the highest rates of relative sea-level rise are in East, South, and SouthEast Asia. The study’s findings show that for the past 20 years, the average sea level rise of 7.8 mm to 9.9 mm annually, was exceptionally high when compared to the global average of 2.6 mm every year.
Researchers Also Took Note of the Occurrence of Land Subsidence
Lead researcher Prof Robert Nicholls stated that sea-level rise is mainly because of the increase in global temperatures. As warming temperatures lead to thermal expansion of water, it subsequently causes glacier melting. On top of sea level rise, sinkage in deltas are occurring, especially where there are cities located in deltas. Man made causes such as oil and gas extraction, sediment resupply, sand extraction or mining, groundwater pumping, and flood defences have been established as the main reasons.
This phenomenon is called land subsidence which is the sudden or gradual sinking of the Earth’s crust because of underground material movement. Professor Nicholls added that 58% of the global coastal population are inhabiting deltas, where land subsidence is now evident.
The cities of New Orleans and Jakarta have recorded the most significant land subsidence at 2 meters and 3 meters, respectively. The main cause of land subsidence in the two cities is the widespread extraction of groundwater in shallow wells.
Note: The research study was funded by the IDRCEC Seventh Framework Programme, the EC Seventh Framework Programme and the EC Horizon 2020 Framework Programme, through which several institutes and universities have been studying the correlation of land subsidence and sea-level rise, and the formulation of global coastal management policies.