The study highlighted that global ocean warming continued unabated in 2025 in response to increased greenhouse gas concentrations and reductions in sulfate aerosols.
Key Findings of the Study
- In 2025, oceans absorbed additional 23 zettajoules (ZJ) of heat, the highest ever recorded since the 1960s.
- Nearly 90% of excess heat trapped by greenhouse gases is absorbed by the oceans, which confirms oceans as the primary buffer of global warming.
- Global average Sea Surface Temperatures (SSTs) in 2025 were among the highest ever recorded (approximately 0.5°C above the 1981–2010 average).
Major Implications of Ocean Warming
- Increased ocean stratification: Warmer surface waters reduce mixing of water layers, leading to lower oxygen supply to deeper waters, reduced nutrient transport to the surface and decline in ocean productivity.
- Increase in Marine Heat Waves: It can lead to coral bleaching, coral diseases, changes in migration and breeding of marine species etc.
- Intense Storms: Warmer oceans provide more heat and moisture to the atmosphere which can lead to more intense cyclones and hurricanes, bringing heavier rainfall and flooding.
- Threat to Marine Ecosystems: Reduced nutrients threaten phytoplankton, the base of marine food chains.
