Sri Lanka’s waters are home to over 200 shipwrecks, each holding a unique story of trade, war, and maritime heritage. Among the most significant are the Godawaya Shipwreck, which dates back over 2,000 years, and HMS Hermes, the world’s first purpose-built aircraft carrier built by British and sunk by Japanese dive bombers during World War II (1931-1945).
Over time, these shipwrecks have transformed into artificial reefs, supporting marine biodiversity and playing a crucial role in ocean ecosystems. However, climate change is now emerging as a major threat to their survival, potentially shortening their lifespan.
“Shipwrecks face multiple threats from climate change,” says Prof. Sevvandi Jayakody of the Department of Aquaculture and Fisheries at Wayamba University of Sri Lanka. “These include extreme weather events, ocean acidification, invasive species, and rising sea temperatures, all of which can accelerate the degradation of wrecks.”
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Human-induced climate change, driven by greenhouse gas emissions such as carbon dioxide (CO₂), not only warms the planet but also increases ocean acidity when the ocean absorbs carbon dioxide from the atmosphere, which lowers the ocean’s pH.
“Globally, research has shown that ocean acidification speeds up the corrosion rate of iron and steel wrecks,” notes Prof. Jayakody. “This is especially concerning for wrecks like HMS Hermes, which may still contain live ammunition. As the metal weakens, there is a risk of explosive materials being exposed.”
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Although ocean acidification studies in Sri Lanka are still in their early stages, the National Aquatic Resources Research and Development Agency (NARA) is monitoring pH levels in coastal waters.
“We take regular measurements from stations on both the east and west coasts,” says Dr. Kanapathipillai Arulananthan director general of NARA. “Additionally, the Norwegian research vessel Nansen is expected to provide further insights into changing ocean parameters in the Northern Indian Ocean.”
Another hidden threat is the rise of invasive species that could now establish in different areas due to warming waters. Changes in ocean temperature and acidity alter microbial activity, leads to faster decomposition of wooden shipwrecks according to research.
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Ballast water from ships can introduce these invasive species to new environments. While differences in salinity, temperature, and acidity once prevented their survival, climate change is making new habitats more suitable for these species, increasing the risk of bioerosion.
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As climate change intensifies, Sri Lanka’s shipwrecks face an uncertain future. Without proactive measures, these historical and ecological treasures could deteriorate beyond recognition, taking with them invaluable insights into the past —and a crucial refuge for marine life in the present.
Mr. Mutukumarana said every shipwreck is unique and when one disintegrates so goes its story, too. The only way forward would be to reduce the rate of global warming.
Malaka Rodrigo, The Sunday Times, 30 March 2025. Full article.
