Ocean heat content is the amount of heat stored in the ocean, and it is one of the clearest indicators of long-term warming because the ocean absorbs most of the excess energy in the climate system. A key distinction is that ocean heat content tracks persistent planetary heat gain more directly than short-term surface variability does, which is why records can keep rising even when yearly surface conditions fluctuate (World Meteorological Organization [WMO], 2026; Pan et al., 2026). For decision-makers, this metric connects long-term warming to sea-level rise, marine heatwaves, and coastal risk (WMO, 2026; Pan et al., 2026).
References
- Pan, Y., Cheng, L., Abraham, J., Trenberth, K. E., Reagan, J., Du, J., Wang, Z., Storto, A., von Schuckmann, K., Zhu, Y., Mann, M. E., Zhu, J., Wang, F., Yu, F., Locarnini, R., Fasullo, J., Huang, B., Graham, G., Yin, X., … Chen, L. (2026). Ocean heat content sets another record in 2025. Advances in Atmospheric Sciences. doi:10.1007/s00376-026-5876-0.