Posidonia in 2050?
We have said many times and we will continue to say it loud and clear: The most serious threat to marine life in the Balearic Sea and the Mediterranean is climate change. Warming waters, rising sea levels, and more frequent extreme weather events have ramifications, such as the disappearance of species and habitats and the arrival of invasive species. This is a cocktail of unpredictable consequences, not only for the balance of marine ecosystems but also for the many economic activities that depend on them, such as fishing and tourism.
The new report from the Intergovernmental Panel on Climate Change (IPCC) published a few days ago – albeit overshadowed by the events in Ukraine – reminds us that current efforts are below what is necessary and predicts that as things stand, the Posidonia meadows will disappear from the Mediterranean by 2050. This is shocking news. We know that Posidonia dies when the temperature rises above 28ºC – as has been the case in recent summers in the Balearic Islands – and that this will happen more and more.
Does this mean that we must stop our efforts to conserve this valuable habitat that provides us with so many benefits? Not at all. First, because the healthier our meadows are, the better they will be able to respond to climate impact; second, because we hope that there will be specimens that can demonstrate resilience and adaptability; and third, because the buried rhizomes (stems) of Posidonia act as a "plug" that prevents the release of all the carbon accumulated under the meadows over hundreds and thousands of years. We cannot afford to lose this valuable habitat, so characteristic of the Mediterranean and the Balearic Islands, or to release the thousands of tonnes of carbon that are now buried beneath.
The IPCC report reminds us of the need to accelerate the energy transition, replacing fossil fuels, such as gas, with renewable energies, such as solar and wind. It also has implications for carbon offset products linked to marine plant conservation. Companies or institutions that want to offset their emissions by investing in seagrass, wetland vegetation, or mangrove conservation and restoration projects will need to review their strategies to confirm that such projects guarantee net emissions savings in the long term. IPCC predictions tell us that Posidonia no longer meets this guarantee.
Yes, Posidonia conservation projects are more necessary than ever because of the multiple benefits this habitat provides, but they do not stand up as carbon offsetting products. The safest option, the one that should take priority, is to reduce emissions rather than offset them by investing in blue carbon projects.
Posidonia in Calvià: thousands of years providing services
A study dates the age of the Posidonia of Illetes (Calvià) at 2,355 years old.