Climate forcing relies on an imbalance between incoming solar energy and outgoing IR energy at the TOA (top of atmosphere). The CERES instruments monitor radiation fluxes at the TOA and has measured this imbalance over the last 11 years . Clouds remain a major uncertainty and large seasonal swings in the “imbalance” are clearly observed. However when averaged over 12 months there remains a small imbalance of about 0.6 +- 0.4 W/m2. Figure 1 shows the CERES data for all skies from March 2000 to 2012 showing a net constant imbalance of about 0.5 W/m2.
This value agrees with the paper by Stephens et al  which quote a TOA imbalance of 0.6 +- 0.4 W/m2. Where is this missing energy going ? Are the Earth’s oceans absorbing the extra energy and if so, how fast is ocean temperature rising ?
Ocean heat content can be derived from the measured temperature profiles of the Earth’s oceans . The heat content is calculated by using the specific heat for a given depth/volume of water and the temperature change. Figure 2 shows the resultant OHC anomaly(change) for the top 700m of global oceans.
AGW theory predicts a TOA “forcing” due to the increase CO2 from pre-industrial times given by F = 5.3 ln(C/C0) W/m2. A step increase from 280 to 400ppm would therefore cause an instantaneous 1.9 W/m2 imbalance at the TOA (forcing). The data show instead a smaller constant imbalance and a small heat absorption by the Oceans. The big picture then is the following:
- For at least the last 12-40 years there has been an imbalance between incoming and outgoing radiation of ~0.6 W/m2 at the TOA.
- The measured heat content of the top 700m of the world’s oceans have apparently absorbed ~ 1.3×10**23 Joules of energy.
The heat content of the oceans is equal to the heat capacity of salt water times the change in temperature integrated over the entire mass of oceans. The total area covered by oceans in Earth is about 3.6×10**14 m2, and the heat capacity of water is 4×10**3 Jkg-1K-1. So this increase in heat content corresponds to a net temperature rise in the top 700m of about 0.15C. Now lets see if the integrated TOA imbalance integrated over the oceans can explain this rise.
Assuming constant net TOA forcing since 1960, the total energy imbalance since then = 0.6*3.6*10**14*(no.of secs since 1960) = 3.4*10**23 (+- 2.3*10**23) joules. That is roughly 2.5 times greater the total ocean heat content (1.3*10**23 joules) but still just about compatible within errors.
Land surfaces warm and cool diurnally and seasonally because they react fast to any changes in climate forcings. If the earth surface was 100% land then radiative energy would always remain in balance via corresponding increases or decreases in surface temperature. The oceans dampen out global temperature changes. What seems to have happened over the last 50 years is that the oceans have been slowly absorbing extra CO2 forcing through moderate temperature rises. Other factors including changes in cloud cover may also play a role in dampening energy balance.
Fig 4 shows the atmospheric CO2 data since 1960. The extra CO2 forcing over this timeframe is predicted to be ~1.2 W/m2 (5.3ln(400/320)). Only about half that amount is now observed in the TOA energy balance, so the rest apparently has been absorbed by the oceans.
CO2 forcing falls logarithmically with concentration so we would expect less absorption over the next 50 years even if emissions continue onwards at the same rate. The oceans would then take around a further 50 years to reach equilibrium . So if levels stabilize after ~2070 the total increase in sea surface temperatures should still be less than ~1C.
 CERES – http://ceres.larc.nasa.gov/compare_products.php
 G. Stephens et al. “An update on Earth’s energy balance in light of the latest global observations” NATURE GEOSCIENCE | VOL 5 | OCTOBER 2012
 http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/index.html & Levitas et al GRL, 2002.