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Ocean science in action: Building a sustainable future for coastal cities
Coastal cities are booming — over a third of the world’s population now lives within 100km of the sea. However, this expansion brings mounting challenges, from climate change-induced risks to human-driven environmental degradation. Ensuring these urban centers remain resilient while preserving marine ecosystems is a pressing global priority.
In this article, we highlight three initiatives endorsed by the UN Decade of Ocean Science for Sustainable Development 2021-2030 (‘Ocean Decade’) that are pioneering innovative solutions through science, technology, policy, and community action to shape the future of coastal cities.
Urban runoff, wastewater, and poorly planned development are reshaping coasts around the world — eroding wetlands, polluting seas, and contributing to ocean warming and acidification. As a result, only 15% of the world’s coastlines remain in their natural state.
From restoring urban seascapes to integrating marine protection into city planning, the three success stories below showcase how the Ocean Decade is harnessing science and knowledge to address these challenges, enhance the resilience of coastal cities to change, and improve the well-being of their inhabitants.
25 February 2025
Reviving Sydney Harbour: Transforming urban seascape
For decades, Sydney Harbour has been at the crossroads of nature and urban expansion, where development and marine life struggle to coexist. The World Harbour Seascape Restoration Programme, led by the Sydney Institute of Marine Science, is working to restore this fractured marine ecosystem, proving that even in the most urbanized waters, marine life can make a comeback. Its Project Restore breaks away from traditional, one-habitat-at-a-time restoration to revive entire marine landscapes – bringing seagrasses, kelp forests, and reefs back to life as interconnected ecosystems.
In a historic first, 3,000 shoots of the endangered Posidonia australis seagrass have been carefully transplanted into Sydney Harbour, laying the foundation for lush underwater meadows. In parallel, 16 tonnes of sea urchins have been removed from two sites where rocky reefs once flourished to allow Ecklonia radiata kelp forests to reclaim their rightful space.
Project Restore Project Manager, Dr Francisco Martinez-Baena says, “we are closely monitoring the restoration sites, with results showing early success. Our Posidonia transplants are looking lush and healthy, with some starting to grow new shoots five months after being planted. On our rocky reefs, we see the first succession of macroalgae appearing, with juveniles of brown algae species such as Sargassum and Padina appearing.”
These efforts aim to develop a blueprint for seascape restoration in urbanized marine environments, a model that could be adapted globally to achieve large-scale improvements in urban harbors.
Predicting and preventing pollution in port areas in Quebec – and beyond
Let’s move from Sydney to Canada and visit the Port of Sept-Îles, Canada’s largest ore port, where artificial intelligence is playing a pivotal role in preventing pollution spikes. Nestled in an archipelago of seven islands, this natural hub ensures year-round ship anchorage, making it key to global trade while also exposing it to heightened environmental pressures from heavy maritime traffic, industrial activity, and coastal development.
Through the Enviro-Actions Project, led by the Northern Institute for Research in Environment and Occupational Health and Safety, autonomous scientific buoys (floating sensors) and monitoring stations are tracking critical water and air quality data in near real-time. But this technology doesn’t just collect data, it then acts on it: when pollution levels rise, preventive alerts are issued to halt further contamination.
“Enviro-Actions is using near-real time monitoring and artificial intelligence for the analysis of big-data and the transmission of preventive alerts to managers,” said Julie Carrière, Ing. Ph. D., INREST Executive Director. “With this system, we make a significant step forward in our ability to follow anthropogenic interactions with the environment and to design concrete measures to make marine-based industrial activities more sustainable.”
