Sea level rising three times as quickly as they were 25 years ago: Research

Rise in water level in the coastal region is the reason for worry in the recent years. At the same time, a new study from European researchers has claimed that sea levels are rising three times as quickly as they were 25 years ago.

The report says that the rise in the sea level will place lives of hundreds of millions living in the coastal areas at risk.

Sönke Dangendorf, an Oceanographer with the University of Siegen charted the increases in sea levels over the 20th century until 2012. The report was published in the journal Proceedings of the National Academy of Sciences.

Highlights of the report

• During the majority of the 1900s, sea levels rose at an average rate of 1.1 millimetres a year.

• The Study Shows Sea Levels Could Rise By 9 Feet in 80 Years.

• The rate at which Global Mean Sea Level (GMSL) rose during the 20th century is uncertain, with

Earlier, a United Nations panel on climate change warned that they expected sea levels to climb between 12 and 39 inches by the year 2100.

Abstract of the report

The rate at which global mean sea level (GMSL) rose during the 20th century is uncertain, with little consensus between various reconstructions that indicate rates of rising ranging from 1.3 to 2 mm⋅y−1. Here we present a 20th-century GMSL reconstruction computed using an area-weighting technique for averaging tide gauge records that both incorporates up-to-date observations of vertical land motion (VLM) and corrections for local geoid changes resulting from ice melting and terrestrial freshwater storage and allows for the identification of possible differences compared with earlier attempts.

The reconstructed GMSL trend of 1.1 ± 0.3 mm⋅y−1 (1σ) before 1990 falls below previous estimates, whereas our estimate of 3.1 ± 1.4 mm⋅y−1 from 1993 to 2012 is consistent with independent estimates from satellite altimetry, leading to overall acceleration larger than previously suggested. This feature is geographically dominated by the Indian Ocean–Southern Pacific region, marking a transition from lower-than-average rates before 1990 toward unprecedented high rates in recent decades.
We demonstrate that VLM corrections, area weighting, and our use of a common reference datum for tide gauges may explain the lower rates compared with earlier GMSL estimates in approximately equal proportion.

The trends and multi-decadal variability of our GMSL curve also compare well to the sum of individual contributions obtained from historical outputs of the Coupled Model Inter comparison Project Phase 5. This, in turn, increases our confidence in process-based projections presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

Abstract part of the story has not been edited and was kept same as provided in www.pnas.org.