Trends and variability in global ocean heat content time series data for the period 2005–2035

Approximately 90 % of the surplus heat generated by anthropogenic greenhouse gas (GHG) emissions is absorbed by the oceans, positioning ocean heat content (OHC) as a fundamental indicator for assessing the progression of climate change. Accurate knowledge of OHC changes at both global and regional levels offers valuable insights into the scope of global warming and its effects on sea-level rise, weather patterns, and ecosystems, and helps refine predictions in climate science. This study models monthly average OHC at 0–700 m and 0–2000 m layers across major ocean basins (Global, Southern Hemisphere, Northern Hemisphere, Pacific, Atlantic, and Indian Oceans) using the Seasonal Autoregressive Integrated Moving Average (SARIMA) method. Utilizing data from 2005 to 2023, the study provides forecasts up to 2035. The results demonstrate that the SARIMA models have correlation coefficients (R) above 0.8544, mean absolute error (MAE) values less than 0.932 × 10²² J, and root mean square error (RMSE) values under 1.222 × 10²² J, indicating highly accurate trends and satisfactory agreement with the observed data. Projected increases in OHC anomalies by 2035 highlight a continued warming trend, particularly in the upper ocean layers.