How much are the world's oceans warming? New method reveals double-digit percentage gaps from climate models

The world's oceans are warming significantly, behaving like a thermometer as they absorb excess heat and experience sea level rise. Geodesy researchers at the University of Bonn have developed a method to measure this ocean warming and compare it to climate model calculations. Their findings, published in Earth System Science Data, reveal substantial discrepancies between measured ocean heat content and model predictions for individual ocean basins, with differences reaching double-digit percentage ranges.

The Indian Ocean, specifically, absorbed an unusually large amount of heat from 2005 to 2015. The study combines measurements from buoys, sea level data from satellites, and gravity data from GRACE satellites to create monthly maps and determine the warming of the entire ocean, providing a more accurate estimate of heat uptake and redistribution.

This approach directly measures the total ocean warming, averaging across all depths, and allows for better global warming calculations. While overall global heat uptake aligns with climate models, basin-specific estimates vary significantly. The Indian Ocean, in particular, absorbed an abnormal amount of heat during the 2005-2015 period.

This research highlights the importance of reliable measurements from satellites and ocean-based monitoring systems to understand the Earth's climate system better. Establishing long-term funding for these measurement systems through global cooperation is crucial to mitigate the consequences of ocean warming and inform climate policy.