The South-West Pacific recorded its second-warmest year on record in 2025, while ocean acidification intensified and sea levels continued to rise, posing growing threats to local economies, coastal communities and low-lying island nations, according to a World Meteorological Organization (WMO) report.
SINGAPORE — The South-West Pacific recorded its second-warmest year on record in 2025, while ocean acidification intensified and sea levels continued to rise, posing growing threats to local economies, coastal communities and low-lying island nations, according to a World Meteorological Organization (WMO) report.
Released during the Southeast Asia Marine Heatwaves Services Workshop in Singapore, the State of the Climate in the South-West Pacific 2025 report said the region's annual mean surface air temperature averaged over land and ocean was about 0.37 degrees Celsius above the 1991-2020 average, making 2025 the second-warmest year on record.
Long-term ocean warming has led to more frequent, longer-lasting and more intense marine heatwaves, with serious consequences for marine ecosystems and the communities and industries that depend on them, the report said.
Marine heatwaves are prolonged periods of extreme heat that can trigger widespread coral bleaching, fish deaths, major disruptions to aquaculture, kelp forest mortality, shifts in species distributions and harmful algal blooms.
In 2025, record-high ocean heat content in the upper 700 metres was observed in waters south of Australia, the southern Tasman Sea, parts of the tropical North Pacific between the Philippines and Hawaii, and locally south of Indonesia's Sumatra Island.
Sea levels in the South-West Pacific rose at an average rate of 3.7 ± 0.03 millimetres a year between 1999 and 2025, the report said.
Meanwhile, ocean waters continued to acidify as they absorbed increasing amounts of carbon dioxide. Nearly the entire South-West Pacific recorded its lowest surface ocean pH values on record in 2025.
Several countries across the region were hit by extreme weather and climate events that caused fatalities and significant economic losses, particularly from tropical cyclones. The deadliest was Cyclone Senyar, the first known system to reach tropical cyclone strength in the Strait of Malacca, affecting more than 10 million people in Indonesia and Malaysia and killing more than 1,200, Xinhua news agency reported.
"Across Asia and the Pacific, heat is intensifying multi-hazard risks, intersecting with food systems, public health, infrastructure and oceans, and placing new pressures on health and livelihoods," said Armida Salsiah Alisjahbana, executive secretary of the United Nations Economic and Social Commission for Asia and the Pacific.
"Early warning and early action save lives when alerts are timely, messages are trusted and last-mile delivery reaches the vulnerable," she said.