The Eurecat technology centre, in conjunction with other European institutions and universities, has conducted a study on the effects of climate change, particularly rising sea levels, on the disappearance of wetlands on the Mediterranean coast. The study points to the need to take action to prevent these formations from vanishing before the end of the century.
The study, undertaken as part of the European REST-COAST project coordinated by the UPC’s Maritime Engineering Laboratory, sets out a range of climate change mitigation measures which could help stabilise wetland areas, such as active or passive habitat restoration and the introduction of sediment bypass systems.
“Coastal wetlands are valuable ecosystems with significant intrinsic biodiversity which deliver outstanding ecosystem services such as carbon sequestration, coastal protection, water purification, food production and habitat provision,” says Carles Ibáñez, director of the Climate Resilience Centre. “This is why their conservation in the Mediterranean is so important.”
As he points out, “the rise in sea level brought about by climate change poses a major threat to the survival of these formations.” The study has thus assessed current risks and identified the main factors which will shape future changes.
The study used an adapted version of the Global Coastal Wetland Model (GCWM) and a database designed to analyse the physical and socio-economic impacts of sea level rise in the Mediterranean which has made it possible to examine various scenarios involving climate change, population growth, coastal management, sediment input and the possibility of wetland migration inland.
In the best-case scenario, the study suggests that the loss would be 8 per cent, while in the most extreme climate change projections and without taking any measures, wetlands would almost entirely disappear with a loss of 92 per cent of their current area.
“In countries such as Egypt, France and Algeria, almost total loss is expected by 2100 if current levels of coastal management and sediment input are maintained,” notes Nuno Caiola, a researcher in Eurecat’s Climate Solutions and Ecosystem Services Unit.
One of the main solutions put forward by the study to mitigate the effects of climate change on wetlands is their migration inland. In all sea level rise projections, “these losses could be halved if migration inland were allowed, for example through active or passive habitat restoration,” comments Carles Ibáñez.
The main drawback “is finding places on the Mediterranean coast which can be used for wetlands due to overpopulation or the allocation of land to housing, farming and industry.”
Furthermore, the outlook improves when sediment input is higher. “Historically, sediment availability has declined sharply in places such as the Ebro, Po and Nile rivers due to dam construction and climate impacts,” says Ibáñez. “Increasing river sediment input would enhance the ability of wetlands to be self-sustaining.” In some cases, sediment bypass systems are being embraced as an alternative.
Even so, this research “shows that coastal management alone will not be enough to save Mediterranean coastal marshes; effective global climate mitigation will also be needed,” adds Nuno Caiola. “Bold climate mitigation and local adaptation measures will be essential to preserve existing coastal wetlands.”
The results of this research have been published by Nature’s Communications Earth & Environment journal in the paper “Large-scale loss of Mediterranean coastal marshes under rising sea levels by 2100” by the Eurecat technology centre, the University of Lincoln, the Christian Albrecht University of Kiel, the Institute for Environmental Studies (IVM) at Vrije Universiteit Amsterdam, the Tour du Valat Research Institute and the Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology.
