Seasonal (3-month) hear energy in the top half-mile of the ocean compared to the 1955-2006 average. Heat content in the global ocean has been consistently above-average (red bars) since the mid-1990s. More than 90 percent of the excess heat trapped in the Earth system due to human-caused global warming has been absorbed by the oceans. NOAA Climate.gov graph. based on data from NCEI.
Ocean Heat Compared to Average
Most of the excess atmospheric heat is passed back to the ocean. As a result, upper ocean heat content has increased significantly over the past few decades.
Change in hear content in the upper 2,300 feet (700 meters) of the ocean from 1993-2020. Between 1993-2019, heat content rose by up to 6 Watts per square meter in parts of the ocean (dark orange). Some areas lost heat (blue), but overall, the ocean gained more heat than it lost. The changes in areas covered with the gray shading were not statistically significant. NOAA Climate.gov image, based on data from NCEI.
Ocean Heat Trends (1993-2020)
Heat absorbed by the ocean is moved from one place to another, but it doesn't disappear. The heat energy eventually re-enters the rest of the Earth system by melting ice shelves, evaporating water, or directly reheating the atmosphere. Thus, heat energy in the ocean can warm the planet for decades after it was absorbed. If the ocean absorbs more heat than it releases, its heat content increases. Knowing how much heat energy the ocean absorbs and releases is essential for understanding and modeling global climate.
* In Original Article
- Sea-level rise caused by climate change and its implications of society, Nobuo MIMURA, No. 7, Proc. Jpn. Acad. Ser. B. 89 (2013), pp. 281-301
- The heat capacity of the ocean is about 1000 times larger than that of the atmosphere, it is estimated that the heat storage in the ocean accounts for about 90% of the heat which the earth absorbed for the past 40 years. (p.285)