Diving in Chuuk Lagoon, Micronesia, offers a glimpse into history. The lagoon is home to a fleet of shipwrecks and aircraft remnants from World War II, remnants of a once-powerful Japanese naval base. These sunken vessels, surrounded by vibrant coral and marine life, attract tourists from around the world. However, this major tourist attraction faces a significant threat: toxic oil is leaking from the deteriorating ships.

Experts warn that climate change is accelerating the decay of these wrecks. Rising water temperatures and increased wave action from extreme weather are corroding the vessels' outer shells. Concerns heightened last month when oil from an old transport ship reached nearby shorelines, damaging mangroves and prompting a state of emergency.

Walter, a historic preservation officer in Chuuk, frequently dives among the wrecks. "When I started diving, I became addicted. It's like another world," he said. His role involves protecting the artifacts within the wrecks, ensuring that tourists do not disturb them. "We keep inventory to make sure tourists don't pick up old guns and things like that," he added, noting the presence of rifles, handguns, and even human remains.

During World War II, over 4,000 Japanese soldiers died when Chuuk Lagoon, then known as "Truk," was bombed by U.S. forces. The attack, described as "revenge for Pearl Harbor," resulted in the sinking of more than 60 vessels and numerous aircraft. Mat McLachlan, a battlefield historian, explained that as the war progressed, Japanese forces were pushed back, making Chuuk a target for Allied bombers.

Today, Chuuk Lagoon is recognized for having one of the highest concentrations of World War II shipwrecks globally, making it a popular destination for scuba divers. Peter Aten, the division chief of commerce and industry in Chuuk, stated, "Eighty percent of our tourists come here because of them."

Concerns about the wrecks began surfacing in the early 2000s when local fishermen reported oil slicks in the lagoon. Following a severe storm, oil washed ashore, leading to an international appeal for assistance from then-leader Manny Mori, who called the wrecks a "ticking time bomb." Since 2017, Japan's Mine Action Service has removed approximately 60,000 liters of oil from the lagoon, but estimates suggest that up to 22 million liters may still be trapped within the vessels.

Aten noted, "What's happening right now with global warming is the rate of deterioration of our shipwrecks has sped up and started to erode much quicker than anticipated." In February, the Australian government funded a study to assess the wrecks, led by maritime archaeologist Matt Carter. The study utilized 3D modeling to evaluate 20 high-risk wrecks, determining that 15 would require cleaning within five to ten years to prevent a large-scale oil spill.

In September, shortly after the study's completion, the Rio de Janeiro Maru, one of the assessed vessels, began leaking oil, creating a thick layer of oil along the shoreline of a nearby village. "Fortunately, the affected villages use rainwater so there is no contamination of their local water, but there have been reported cases of dizziness due to the fumes and smell of the oil," Aten said. A state of emergency was declared, and Micronesian President Wesley Simina addressed the issue at the UN General Assembly, highlighting the overwhelming scale of the problem.

Addressing the oil removal poses challenges. Carter explained that cleaning a single wreck in Chuuk could cost over $10 million. The logistical difficulties of transporting equipment to remote locations like Chuuk increase costs significantly. Additionally, there is no legal obligation for the countries responsible for the wrecks to assist in their cleanup, as Micronesia was not an independent state during World War II, placing the wrecks in a legal grey area.

Donald Rothwell, a maritime expert, noted that while there is growing awareness of the issue affecting small island states, a global settlement will take time. In the meantime, Chuuk leaders have applied to have the wrecks designated as a UNESCO World Heritage Site to raise awareness and support for the issue. "It's obvious that this is just the beginning," Aten said. "We have 63 shipwrecks in our lagoon, and it would be a devastation if they all start leaking."