China's homegrown marine heatwave forecasts now cover the globe

China has launched a global marine heatwave forecasting system, building on a domestic version first introduced in 2024. The system was independently developed by the National Marine Environmental Forecasting Center under the Ministry of Natural Resources, the ministry said on Friday. Weekly forecasts are posted at nmefc.cn/ybfw/heatWave.

When sea surface temperatures exceed the local climatological average for five or more consecutive days, it is classified as a marine heatwave. According to the World Meteorological Organization, 2025 set a new record for ocean heat content for the ninth consecutive year, with around 90% of the global ocean surface experiencing at least one marine heatwave.

As the world grapples with global warming, marine heatwaves have emerged as a new type of threat to fishing industry, environment, and marine life. They have been reported to have accelerated the collapse of Caribbean coral reefs, caused the cancellation of anchovy fishing in Peru, and may be amplifying hurricane damage.

Built on China's self-developed "Mazu" ocean circulation model, the forecasting system can predict the development of marine heatwaves across global oceans over the coming week, including their formation, evolution, geographic spread and changes in intensity.

China says the forecasting system will strengthen its ability to predict and respond to marine heatwaves, while also supporting ocean conservation, the marine economy and maritime security. The forecasting center plans to further improve the system's accuracy and extend forecasting lead times, while enhancing early warning and emergency response capabilities. It also aims to deepen participation in international ocean governance by contributing China's expertise and resources to the protection of global marine ecosystems.