June 2nd, 2017
A new study published in the ‘Proceedings of the National Academy of Sciences (PNAS)’ revealed that sea levels are rising three times as quickly as they were 25 years ago, placing hundreds of millions of people living in coastal areas at risk.
The ocean levels on Earth are rising less than a half-inch per decade before 1990. But from 1993 to 2012, the water rises for about 1.22 inches for each decade, says the study led by Sonkë Dangendorf, an oceanographer from the University of Siegen in Germany.
“The acceleration in global mean sea-level rise is much larger than previously thought,” said Dangendorf, as reported by Sputnik News. “It underlines that sea-level rise is a serious threat,” he added.
Rising sea level is believed to be primarily caused by global warming. As the Earth warms, cold and icy areas of the world become warmer. Therefore, the ice melts and flows into the sea, causing water levels to rise. While this is no secret to the environmental community, previous studies have not charted such a shockingly high rate of sea levels rising.
According to Dangendorf, fast rising sea level is a result of melting ice sheets in Greenland and Antarctica, a factor he believes was understated in previous estimates. “We have always had a great uncertainty over the contribution of large ice sheets, which store 100 times more sea-level equivalents than glaciers,” he said.
Apart from this, the thermal expansion of the warming ocean also contributes to rising sea level.
The new study is based on data from tide gauges, devices that have been used measure changes in sea level since the 19th century. They mostly became obsolete in the 1990s, but their data is still valid today. From 1992 onwards, researchers have mostly relied on satellite data instead.
United Nations Intergovernmental Panel on Climate Change in its ‘The Fifth Assessment Report’ predicted that the global sea level could rise between 4 feet to slightly over 10 feet by 2100 which depends on the fossil fuel emissions.
Earlier, a UN Environment report estimated that nearly 40 million Indians will be at risk from rising sea levels by 2050, with people in Mumbai and Kolkata having the maximum exposure to coastal flooding in future due to rapid urbanisation and economic growth but have limited capacity to adapt due to their fixed location.