New York – October 03, 2026 -- A new episode of the climate interview series Net Zero Speaks tackles a question coastal communities can no longer ignore: what happens when rising seas meet sinking land. The episode, produced by the Planet Classroom Network with the Protect Our Planet (POP) Movement, features Professor Marco Marani of the University of Padova, Director of the Centre for Climate Change Impacts (CRITICAL).
Hosted by youth climate advocate Ivan Ransom and produced by Gillian Cameron, the conversation centers on what Marani calls 'relative sea-level rise' -- the combined effect of ocean rise and land subsidence. He points to Venice and major river deltas as places where natural sediment compaction and human activity speed up sinking and worsen flood risk.
Salt marshes have already lost half their global area
Marani highlights the overlooked role of salt marshes and coastal wetlands, which cut flood damage from storm surges and support fisheries and local biodiversity. Their survival depends on building elevation through sediment and organic material, a process now outpaced by accelerating sea-level rise. By his estimate, roughly 50 percent of global marsh areas have already drowned.
Venice's MOSE barriers protect the city but starve its marshes
Venice serves as Marani's central case study. The MOSE storm-surge barrier system is critical to the city's survival, but blocking exceptionally high tides also blocks the natural sediment flow that nourishes salt marshes. Marani argues engineering fixes need to account for biological and geological processes to hold up over time.
Marani calls for managed retreat where cities can't be saved
He outlines three priorities for coastal leaders: investing in youth education, pairing climate science with engineering to guide nature-based defenses, and planning managed retreat for regions that cannot be protected the way Venice is. Cathy Rubin, Founder and CEO of Planet Classroom, said the episode shows that protecting coastlines requires understanding living ecosystems and acting before climate impacts narrow the options available.
Net Zero Speaks with Marco Marani premiered today on the Planet Classroom Network YouTube Channel, part of a series that has produced more than 50 episodes on net-zero solutions and policy.