OSLO, (Reuters) – Sea level rise in the past two decades has accelerated faster than previously thought in a sign of climate change threatening coasts from Florida to Bangladesh, a study said yesterday.
The report, reassessing records from more than 600 tidal gauges, found that readings from 1901-90 had over-estimated the rise in sea levels. Based on revised figures for those years, the acceleration since then was greater than so far assumed.
The report said the earlier readings were incomplete or skewed by local factors such as subsidence.
The new analysis “suggests that the acceleration in the past two decades is 25 percent higher than previously thought,” Carling Hay, a Canadian scientist at Harvard University and lead author of the study in the journal Nature, told Reuters.
The study said sea level rise, caused by factors including a thaw of glaciers, averaged about 1.2 millimetres (0.05 inch) a year from 1901-90 – less than past estimates – and leapt to 3 mm a year in the past two decades, apparently linked to a quickening thaw of ice.
Last year, the U.N.’s Intergovernmental Panel on Climate Change (IPCC) estimated the 1901-90 rate at 1.5 mm a year, meaning less of a leap to the recent rate around 3 mm.
The Harvard-led study said the new findings might affect projections of the future pace of sea level rise, especially those based on historical trends.
John Church, a top IPCC author at the Commonwealth Scientific and Industrial Research Organisation in Australia, told Reuters he did not expect any impact on the IPCC’s core sea level projections, which are not based on past trends.
