On April 4 2007 Climate Science published the following weblog
A Litmus Test For Global Warming – A Much Overdue Requirement
In that weblog, I wrote
“A figure, such as Figure 8 in Willis, J.K., D. Roemmich, and B. Cornuelle, 2004: Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales. J. Geophys. Res., 109, C12036, doi: 10.1029/2003JC002260.
should be widely communicated each year (or more frequently). For example, as a requirement to NOT reject the IPCC claim for global warming, Climate Science proposes that on the scale presented in Figure 3 in Willis et al, the left axis in their Figure 8 must exceed the following values in each year
2003 8*10**22 Joules
2004 9*10**22 Joules
2005 10*10**22 Joules
2006 11*10**22 Joules
2007 12*10**22 Joules
2008 13*10**22 Joules
2009 14*10**22 Joules
2010 15*10**22 Joules
2011 16*10**22 Joules
2012 17*10**22 Joules”
This is an accumulation of heat of 1 * 10**22 Joules per year. We now have data to assess what actually occurred in terms of this metric of global warming up through the end of 2008 (i.e. see the Figure in Pielke (2008), Figure 1 in Willis et al (2008) and personal communication from Josh Willis to extend the data to the end of 2008).
The use of the ocean heat content change as the most appropriate metric to diagnose global warming was reported in
Levitus, S., J.I. Antonov, J. Wang, T.L. Delworth, K.W. Dixon, and A.J. Broccoli, 2001: Anthropogenic warming of Earth’s climate system. Science, 292, 267-269
Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335.
In a 2008 Climate Science weblog
Comparison of Model and Observations Of Upper Ocean Heat Content,
“The conclusion in Hansen et al. 2005 that the “Earth is now absorbing 0.85 ± Watts per meter squared more energy from the Sun than it is emitting to space” is well supported by their modeling results for the ten years or so ending in 2003.”
With respect to the heating rate, in the paper
Hansen, J., L. Nazarenko, R. Ruedy, Mki. Sato, J. Willis, A. Del Genio, D. Koch, A. Lacis, K. Lo, S. Menon, T. Novakov, Ju. Perlwitz, G. Russell, G.A. Schmidt, and N. Tausnev, 2005: Earth’s energy imbalance: Confirmation and implications. Science, 308, 1431-1435, doi:10.1126/science.1110252,
“Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols among other forcings, calculates that Earth is now absorbing 0.85±0.15 W/m2 more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years.”
See also the response by Jim Hansen to a comment by Christy and Pielke Sr [which Science refused to publish], where Hansen wrote me with respect to their GISS model predictions that
“Our simulated 1993-2003 heat storage rate was 0.6 W/m2 in the upper 750 m of the ocean.”
He further writes
“The decadal mean planetary energy imbalance, 0.75 W/m2, includes heat storage in the deeper ocean and energy used to melt ice and warm the air and land. 0.85 W/m2 is the imbalance at the end of the decade.”
Thus, the best estimate value of 0.60 Watts per meter squared given in Hansen et al can be used, as a conservative value, to calculate the heat change in Joules that should be expected in the upper ocean data from 2003 to the present, as an update to results reported on Climate Science on June 5 2008.
The observed best estimates of the observed heating and the Hansen et al prediction in Joules in the upper 700m of the ocean are given below:
OBSERVED BEST ESTIMATE OF ACCUMULATION Of JOULES [assuming a baseline of zero at the end of 2002].
2003 ~0 Joules
2004 ~0 Joules
2005 ~0 Joules
2006 ~0 Joules
2007 ~0 Joules
2008 ~0 Joules
HANSEN PREDICTION OF The ACCUMULATION OF JOULES [ at a rate of 0.60 Watts per meter squared] assuming a baseline of zero at the end of 2002].
2003 ~0.98 * 10** 22 Joules
2004 ~1.96 * 10** 22 Joules
2005 ~2.94 * 10** 22 Joules
2006 ~3.92 * 10** 22 Joules
2007 ~4.90 * 10** 22 Joules
2008 ~5.88 * 10** 22 Joules
2009 ~6.86 * 10** 22 Joules
2010 ~7.84 * 10** 22 Joules
2011 ~8.82 * 10** 22 Joules
2012 ~9.80 * 10** 22 Joules
Thus, according to the GISS model predictions, there should be approximately 5.88 * 10**22 Joules more heat in the upper 700 meters of the global ocean at the end of 2008 than were present at the beginning of 2003.
For the observations to come into agreement with the GISS model prediction by the end of 2012, for example, there would have to be an accumulation 9.8 * 10** 22 Joules of heat over just the next four years. This requires a heating rate over the next 4 years into the upper 700 meters of the ocean of 2.45 * 10**22 Joules per year, which corresponds to a radiative imbalance of ~1.50 Watts per square meter.
This rate of heating would have to be about 2 1/2 times higher than the 0.60 Watts per meter squared that Jim Hansen reported for the period 1993 to 2003.
While the time period for this descrepancy with the GISS model is relatively short, the question should be asked as to the number of years required to reject this model as having global warming predictive skill, if this large difference between the observations and the GISS model persists.