World Environment Day 2026: Restoring the blue lungs of the Eastern Mediterranean

Lemnos' underwater forest stores the annual emissions of a city’s cars, counting for more than 270,000 tons of carbon dioxide.

On the occasion of World Environment Day 2026, iSea, the Hellenic Ornithological Society / Birdilife Greece, and the Municipality of Lemnos, partners of the “Reviving Lemnos” project celebrate the launch of the pilot restoration of one of the Eastern Mediterranean's most important marine ecosystems!

Known as the "blue lungs" of the Mediterranean, Posidonia meadows are among the world's most effective carbon sinks. The meadow of Lemnos island alone stores more than 270,000 tons of carbon dioxide making it a powerful ally in the fight against climate crisis, while supporting biodiversity, fisheries, coastal protection and local livelihoods. Stretching more than 20 kilometers from the coastline, beyond the boundaries of the Natura 2000 protected area and into international waters and reaching depths of up to 30 metres, it supports more than 66 marine species, with their diversity exceeding those recorded in many other areas of Greece.

Lemnos is home to one of the Mediterranean’s largest underwater forests and the restoration initiative, led by the environmental organisation iSea, marks a significant milestone in safeguarding. This extensive interconnected meadow covers 139.43 km² and serves as a critical nursery ground for marine life. Healthy Posidonia meadows mean healthy seas. thriving wildlife and stronger coastlines. They provide shelter for countless marine species, protect coastlines from erosion, improve water quality and absorb carbon at rates that exceed terrestrial forests, while storing it for millennia.

“Reviving Lemnos” project, aims to restore and strengthen this valuable ecosystem through science-based conservation actions, stakeholder engagement and long-term restoration efforts. The recently completed pilot restoration phase will lay the foundation for the restoration of more than 10.000 shoots across an area of 400 m² in the coming years.

This pilot phase also coincides with the international project meeting in Lemnos, bringing together project partners from across Europe to assess progress, exchange expertise and coordinate the next steps of this ambitious marine and coastal restoration initiative.

"Restoring the blue lungs of the Eastern Mediterranean requires both scientific innovation and strong local partnerships," said Nikoletta Sidiropoulou, Project Manager at iSea. "This week we successfully completed the transplantation of more than 250 Posidonia shoots, an important pilot step that will guide our future restoration efforts. The knowledge that will be gained through monitoring will provide a valuable roadmap for scaling up restoration and ensuring long-term conservation success in Lemnos."

As the "Amazon of the Sea," the Posidonia meadow of Lemnos demonstrates the vital role marine ecosystems play against climate crisis and biodiversity loss simultaneously. Protecting and restoring these underwater forests is not only an investment in nature, but also in the resilience, prosperity and future of Mediterranean communities.

The “Reviving Lemnos” project is one of seven large-scale programs funded by the Endangered Landscapes & Seascapes Programme dedicated to the restoration of Europe’s landscapes. Find more about “Reviving Lemnos” project here: https://www.birdlife.org/landscape-nature-restoration/lemnos-island/

Contact Information:

Environmental Organisation iSea: Nikoletta Sidiropoulou, Project Manager, tel: +30 2313 090696, email: nikoletta.sidiropoulou@isea.com.gr