SYDNEY, June 27 (Xinhua) -- The rate at which sea levels have risen over the past 25 years has doubled, according to research released on Tuesday, in what the researchers have hailed as the first "continuous measurement" of sea levels over that period.
The research conducted at Australia's CSIRO in Hobart is to assess the incremental levels of increase in the rate of the rises in sea level, and found that it had increased from 2.2 mm per year in 1993, to 3.3 mm per year by 2014.
The readings were taken using altimetry, which is conducted by using a satellite to measure the time that it takes for a radar pulse to be transmitted from a satellite to the sea, and then back to the receiver on the satellite - which can then be combined with satellite location data to get an accurate reading.
Zhang Xuebin, a senior research scientist who headed the project at the Oceans and Atmosphere laboratory at the CSIRO, told Xinhua on Tuesday that this was a wide ranging study that included all possible measurements for accuracy.
"This study was about checking the rising sea level, and the contribution from all the different components, for example, the melting of ice sheets. We included everything, not just the level from the altimeter," Zhang said.
The scientist, whose work is sponsored by the China Scholarship Council, said by using these satellite altimetry readings, it is possible to get detailed analysis using the "empirical model composition."
"Using this technique we can get changing levels over the past 20 years and find they have increased from the first decade to the second decade." Zhang said.
The research discovered that the global mean sea level (GMSL) has risen at a faster rate over the course of the past 25 years, with the acceleration expected to continue, however as this is the first time truly accurate data has been collected, too much speculation should be avoided.
"Obviously you can not just do policies solely based on this 25 years, I think it's not the right way to do it. This is a 25-year measurement and should provide a very good baseline, because the future climate predictions are mainly based on the climate models," Zhang said.
"We need to calibrate the validity of the climate model, so this altimetry is the only global continuous measurement of sea level so over the past 25 years, so we now have a continuous measurement."
This means of having truly reliable and concrete data is crucial, according to the learned scientist, who said that this study has provided a "benchmark" for all future assessments of the impact of climate related activities on sea level conditions.
"It is critical for the world to closely assess what has happened in this 25 year period and use that as a benchmark to analyze into the future and create climate models," Zhang said.
"It's critical I think for all the current models to modify their parameter risings and reproduce what we discovered in this study, before we can do something about the future."
