In the last thirty years, the speed at which the sea level rises in Lanzarote as a result of climate change has more than doubled, according to a study led by the Spanish Institute of Oceanography (IEO).
Currently, the sea level in Lanzarote is rising three millimeters per year, more than double what the measurements taken in 1993 showed. The data comes from tide gauges installed in the ports, in combination with altimetry data, that is, measurements taken from space by artificial satellites.
In statements to La Voz de Lanzarote, the author of the study, Manuel Vargas, explains that in the long term many coasts will be lost. “If we continue emitting greenhouse gases at the rate we are doing, the sea level rise will be 80 centimeters or one meter.”
"With 80 centimeters, the sea will advance tens of meters on the beaches"
“In cliff areas it will not be a problem, but in beach areas, especially if it has a slight slope, 80 centimeters vertically translates into an advance of the sea inland by tens of meters”, he exemplifies.
Vargas clarifies that the projections are based on current data and future scenarios will depend on the amount of greenhouse gases that we continue to emit into the atmosphere.
“We have already had 20 centimeters of rise since the pre-industrial era, if we drastically reduced greenhouse gas emissions, we would surely be moving in 50-60 centimeters by the end of the 21st century. The problem is that the process continues to accelerate with the reduction of ice”, he warns.
The data from Arrecife from the mid-20th century, which only took into account measurements with tide gauges, were around 0.6 millimeters per year, since 1993 they have been around 1.4 millimeters. However, according to the IEO study, which combines data taken at sea with satellite images, the speed is much higher and is equivalent to three millimeters per year.
Water heating and melting of the ice
The work, recently published in the journal Geosciences, analyzes monthly series of sea level in different ports around the Atlantic and Mediterranean coasts of the Iberian Peninsula, as well as the Canary and Balearic archipelagos.
For the analysis, developed by the IEO in collaboration with the Mediterranean Institute of Advanced Studies (IMEDEA), data from tide gauges dating back to the early 1940s have been used, as well as altimetry data from satellites since 1993.
The scientific team has also analyzed the contribution of different factors to this rise in sea level, and has concluded that in all the regions analyzed, part of this rise is due to the heating of the waters, which produces the thermal expansion of the same and the consequent increase in its volume.
This contribution has been quantified at about 0.8 millimeters per year, but the most important factor is the increase in water mass, presumably originating in the melting of the ice in Greenland and Antarctica, a factor that would have contributed to the rise of approximately 1.4 millimeters per year.
The study highlights the need to maintain surveillance and monitoring systems of the seas to "know exactly the changes that are taking place in them", according to the scientist.
