We quantify the interannual-to-decadal variability of the heat content (mean temperature) of the world ocean from the surface through 3000-meter depth for the period 1948 to 1998. The heat content of the world ocean increased by ∼2 × 10 23 joules between the mid-1950s and mid-1990s, representing a volume mean warming of 0.06°C. This corresponds to a warming rate of 0.3 watt per meter squared (per unit area of Earth's surface). Substantial changes in heat content occurred in the 300- to 1000-meter layers of each ocean and in depths greater than 1000 meters of the North Atlantic. The global volume mean temperature increase for the 0- to 300-meter layer was 0.31°C, corresponding to an increase in heat content for this layer of ∼10 23 joules between the mid-1950s and mid-1990s. The Atlantic and Pacific Oceans have undergone a net warming since the 1950s and the Indian Ocean has warmed since the mid-1960s, although the warming is not monotonic.

[1] We provide updated estimates of the change of ocean heat content and the thermosteric component of sea level change of the 0-700 and 0-2000 m layers of the World Ocean for 1955-2010. Our estimates are based on historical data not previously available, additional modern data, and bathythermograph data corrected for instrumental biases. We have also used Argo data corrected by the Argo DAC if available and used uncorrected Argo data if no corrections were available at the time we downloaded the Argo data.

We provide estimates of the warming of the world ocean for 1955–2008 based on historical data not previously available, additional modern data, correcting for instrumental biases of bathythermograph data, and correcting or excluding some Argo float data. The strong interdecadal variability of global ocean heat content reported previously by us is reduced in magnitude but the linear trend in ocean heat content remain similar to our earlier estimate.

[1] For the 1955 -2003 period, the thermal expansion of the 0 -700 m layer of the World Ocean contributed approximately 0.33 mm/year to global sea level rise. About half of this thermosteric trend is due to warming of the Atlantic Ocean. Approximately one third of the total thermosteric rise is due to the warming of the Pacific Ocean. For the period of available TOPEX/Poseidon (T/P) satellite altimetry data (1993 -2003), the linear trend of thermosteric sea level (0 -700 m) is 1.23 mm/year, 60% of which is due to the trends in the Pacific Ocean. For the 0-3000 m layer of the entire World Ocean, the linear trend of thermosteric sea level is 0.40 mm/year for 1955 -1959 through 1994 -1998. For the 50°S-65°N region that we previously reported (Antonov et al., 2002) which was characterized by a 0.50 mm/year trend for 1955 -1959 through 1992 -1996, our new estimate is 0.47 mm/year for this same period.