Deep-ocean contribution to sea level and energy budget not detectable over the past decade

• Published in: Nature climate change Vol. 4; no. 11; pp. 1031 - 1035
• Main Authors: Llovel, W., Willis, J. K., Landerer, F. W., Fukumori, I.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2014; Nature Publishing Group
• Subjects: 704/106/694/2739; 704/106/829/2737; Climate Change; Climate Change/Climate Change Impacts; Climate system; Climatology. Bioclimatology. Climate change; Earth; Earth, ocean, space; Energy balance; Environment; Environmental Law/Policy/Ecojustice; Exact sciences and technology; External geophysics; Global climate; Marine; Meteorology; Ocean warming; Ocean, Atmosphere; Oceans; Physics of the oceans; Sciences of the Universe; Sea level; Thermohaline structure and circulation. Turbulence and diffusion; Water column; Space remote sensing; climate warming; GRACE satellite; Satellite observation; Sea level rise; energy balance; Deep water; ocean-atmosphere interaction; Drifting float; global change; Profiling float; warming; Observation data; sea level; altimetry; climate change
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/nclimate2387

As the dominant reservoir of heat uptake in the climate system, the world’s oceans provide a critical measure of global climate change. Here, we infer deep-ocean warming in the context of global sea-level rise and Earth’s energy budget between January 2005 and December 2013. Direct measurements of ocean warming above 2,000 m depth explain about 32% of the observed annual rate of global mean sea-level rise. Over the entire water column, independent estimates of ocean warming yield a contribution of 0.77 ± 0.28 mm yr −1 in sea-level rise and agree with the upper-ocean estimate to within the estimated uncertainties. Accounting for additional possible systematic uncertainties, the deep ocean (below 2,000 m) contributes −0.13 ± 0.72 mm yr −1 to global sea-level rise and −0.08 ± 0.43 W m −2 to Earth’s energy balance. The net warming of the ocean implies an energy imbalance for the Earth of 0.64 ± 0.44 W m −2 from 2005 to 2013. The global ocean is a major heat reservoir of the climate system. This study investigates ocean warming for 2005–2013 in the context of global sea-level rise and Earth’s energy budget, and finds that the deep ocean (below 2,000 m) has contributed negligibly to both.