In a few decades, when you comb gray hair and can get on the bus with your pensioner’s card, you may look at the beach where you used to play in the summers of your childhood and tell your grandson with a deep air: “When I was a child, all this It was sandy.” He may not pay you the slightest attention; but it will be true. If you’re walking right along the edge, soaking your calves in the waves, chances are you’re stepping on ground that years ago was more sheltered from the tide.
The sea level is rising. And more will. You won’t have to pull memories to find out. The studies of a priori organisms as solvent as the Intergovernmental Group of Experts on Climate Change (IPCC) say so —and clearly, too. Just a few months ago, in 2021, Professor Robert Kopp, author of the chapter dedicated to the Earth’s oceans in the latest report by the body, explained it clearly. Since 1970 the global level is rising at an accelerated rate. So much so that in the last century it has experienced its greatest increase in at least 3,000 years.
A coastline with an expiration date
“During the last decade, the global average sea level has risen at a rate of about four millimeters per year. This increase is mainly due to two factors: the melting of ice in mountain glaciers and at the poles and the expansion of the water in the ocean as it absorbs heat,” Kopp explained in an article published in The Conversation the last summer. Only between 2013 and 2019, the time that elapsed between the IPCC reports, did experts see signs that the loss of the ice sheet is “accelerating”.
According to Kopp’s calculations, it is likely that by the middle of this century we will find that the level of the seas has increased, on average, between 15 and 30 centimeters. The worst thing is that this drift can hardly be stopped. “The turnaround to 2050 is largely set,” she warns. His calculations are in tune with those of other institutions. In February NASA and other US government agencies, including NOAA, published a report concluding that in the next 30 years the seas could rise as much as in the last century.
Experts estimate that along the coasts of the United States the sea level will rise between 25 and 30 centimeters. Beyond 2050, the scenario is complex and depends on what we do in the coming years, but Kopp points out that, if we do not change, we maintain emissions and allow temperatures to rise between three and four degrees by 2100, the planet will will face a rise in sea level of approximately 0.7 meters. In the worst case scenario, with heavy contamination, he even speaks of 2 meters at the end of the century.
In Spain, with 8,000 kilometers of coastline, that would be a considerable problem. The report on climate change presented in 2021 by the Government draws a scenario in which the level of flooding in part of the country’s coasts —Atlantic, Cantabrian and Alborán Sea— could grow by 8% by 2040. In the Canary Islands it would increase by 6 % and between 2 and 3% in the rest of the Mediterranean and the Gulf of Cadiz. The study points to the risk of million dollar flood damage in the most exposed coastal cities and how rising seas would also harm the tourism sector.
It is not necessary to imagine how the country would change with the rise of the seas. Climate Central, an organization dedicated to climate change research, has produced online maps where you can see in detail how different scenarios of sea level rise would affect our cities. Some correspond to the calculations of the experts in the medium term; others go further and allow us to see what would happen if the sea level grew exponentially.
Climate Central’s interactive tool allows you to see what would happen, for example, with increases of between 0.5 and 30 meters and different circumstances, such as an unchecked rise in pollution, moderate control or even an “extreme reduction” in emissions. of carbon.
His projections are interesting above all to explore how the rise in the level of the oceans can affect the flood risk and how exposed the sensitive areas are, especially if strong swells and factors that aggravate it are added to the rising waters.
Climate Central also provides forecasts for some cities. For example, he calculates that it is likely that if we do not control pollution levels between 2170 and 2200, the rise in sea level will reach 2.5 meters in Barcelona. The forecast is similar for other areas of the Spanish Mediterranean, such as L’Estartit, Valencia, Alicante, Almería or Palma de Mallorca. If we applied strict policies and managed to drastically reduce CO2 emissions, the scenario would be somewhat better and it would take longer to see that level of increase. The same happens in the Atlantic and Cantabrian.
Climate Central simulations also show the urban areas that would be affected by sea level rise. In the case of Vigo, for example, it reveals that with a rise of only two meters part of its filling would be affected. With a higher rise, five meters, the impact would extend even to part of the Lagares riverbed, which crosses the city.
The impact would also be noticeable in estuaries such as Avilés, San Esteban de Pravia, Foz or Betanzos. Other points where the increase in level would be strongly felt, both due to its proximity to the sea and altitude, are the Ebro Delta, the Llobregat Delta and the mouth of the Guadalquivir.
The archipelagos would also suffer the effect in a marked way. As already stated in the Balearic Sea Report, the western Mediterranean and specifically the Balearic Islands are considered one of the most vulnerable points to the rise in sea level. According to their data, there are scenarios that contemplate increases of between 57 and 75 centimeters by the end of the century, which would imply that the beaches would regress considerably: between seven and 50 metersdepending on the case.
Climate Central maps also reflect coastal risks. For example, in the case of Valencia they show a wide strip that would be affected by a water level of 10 meters above the high tide line. It is a high figure, but it would not be related only to a rise in sea level. The study proposes this scenario with the sum of several factors: the variation of the sea, the tides and a storm surge. The maps also show areas that would remain underwater depending on the passage of time, taking into account the projections of the experts.
After all, you may not need to wait for retirement and grandchildren to appreciate how rising oceans blur the shorelines you knew as a child.
Pictures | Climate Central
George is Digismak’s reported cum editor with 13 years of experience in Journalism