A team of scientists has studied satellite data for 25 years and has calculated that sea level does not increase steadily, but is accelerating. If the trend continues, the total increase in sea level could be twice as high as the previous projections for the year 2100. It has been observed for decades that sea level is rising, with waves breaking about 2.6 inches more on average in 2014 than in 1993. To study how fast it is rising, the researchers observed the altimeter measurements collected during the last 25 years for satellites such as TOPEX / Poseidon and the three Jason satellites, as well as data from terrestrial tide gauges and climate simulations.
In total, the researchers calculated that the rate of sea level rise accelerates by approximately 0.08 mm per year. If left unchecked, that trend could mean that the seas would increase at least 10 mm per year by the end of the century, which would wreak havoc on the coastal cities of the world. "This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total increase in sea level by 2100 compared to projections that imply a constant rate: more than 60 cm instead of 30.
The satellite altimeter data alone does not offer a clear enough picture, due to fluctuations caused by El Niño and La Niña weather patterns, and events such as volcanic eruptions. The researchers say their findings are just the beginning. The 25-year period studied so far is long enough to detect acceleration, but the ongoing Jason-3 project and other altimetric satellites, as well as more advanced ground stations, will collect more data.