The maximum temperature recorded during that same year was 29.26 ºC, well above the threshold above which mortality of this protected plant increases
Ibiza, 09-08-2025 – The sea water temperature in the Bay of Talamanca exceeded 28ºC for 11 consecutive days between August 4 and 14, 2024, “the threshold at which the mortality of Posidonia oceanica increases,” explains IbizaPreservation. The data comes from in-situ temperature sensors installed by the environmental organization GEN-GOB and financed by IbizaPreservation, thanks to the support of the women’s fashion brand Hoss Intropia, and has been analyzed by the Sustainability Observatory of the environmental foundation, within the framework of its 2024 Sustainability Report , currently being prepared with funding from the Consell Insular d’Eivissa.
The highest temperature recorded in the area that same year was 29.26°C on August 13 at 4:00 PM . This temperature level, maintained for several days in a row, causes prolonged stress to this marine plant, an emblem of Mediterranean biodiversity and key to coastal protection, laments IbizaPreservation. In 2023, an alarming maximum temperature of 30.07°C was also reached on August 24, with a total of 40 days recorded with temperatures above 28°C.
“The fact that temperatures exceed 28 degrees Celsius for several days in the middle of summer is worrying because it directly compromises the health of the Posidonia, as demonstrated in a 2010 study conducted by scientists Núria Marbà and Carlos Duarte,” explains Elisa Langley , coordinator of the Sustainability Observatory at IbizaPreservation. “Sea temperatures are reaching levels that were exceptional years ago and are now beginning to recur every season,” she warns.
Posidonia oceanica is a marine plant endemic to the Mediterranean that forms underwater meadows essential for marine biodiversity, water oxygenation, and seabed stabilization. It also acts as a natural barrier against beach erosion. “When sea temperatures exceed 28°C for several consecutive days, the plant enters a phase of thermal stress , which increases its mortality rate,” explains the Observatory.
GEN-GOB points out that the rise in sea temperature is not an isolated phenomenon, but a consequence of the advance of climate change . “The projections for climate change are very bad,” warns Xisco Sobrado , coordinator of the Marine Area of this environmental group, who points out that the Paris Agreement establishes the need to reduce emissions by half compared to the levels of the 1990s to limit global warming to 1.5 ºC above pre-industrial values. “However, last year we already exceeded those thresholds and the trend is very worrying,” he points out. In his opinion, if we want to protect both the Posidonia oceanica meadows and the human activities that depend on them, it is essential to apply fundamental measures such as “ reducing the number of tourists who visit us each year and implementing policies to decrease tourism .”
Along these same lines, the IbizaPreservation Sustainability Observatory emphasizes that, given the impossibility of controlling current sea temperatures, it is urgent to act on the other factors that threaten the posidonia . “We must protect it from illegal anchoring, dumping, and the impact of invasive species. We must act, or this plant will be unable to resist. Reducing our carbon footprint also increases our resilience to climate change,” Langley concludes.
