Energy Imbalance and Ocean Heat Storage: No Proof of AGW
S. Fred Singer

Energy Imbalance and Ocean Heat Storage: No Proof of AGW
S. Fred Singer (Aug 5, 2005)

The claim [1] that existence of a global imbalance of energy flux is the "smoking gun" for anthropogenic global warming (AGW) faces numerous problems. It relies on a model-calculated energy imbalance, which has not been validated by satellite measurements at the top of the atmosphere but is supposedly confirmed by a measured [2] (global mean) increase in ocean heat content. But how good is this claimed agreement?

Let's be clear about one thing. There is always an imbalance - in the sense that there is more (or less) energy entering the atmosphere (as net solar radiation, i.e., incident minus reflected SW flux) than is emitted into space in the form of IR energy. But such an imbalance can only be temporary; that is, over time it must average out to zero. And what happens to this temporary imbalance, which is either positive or negative? Some of goes into melting or making ice - but most is stored in the ocean. In principle, therefore, there is nothing wrong with the method used by Hansen. But even if it were to give correct values for the imbalance, this does not prove that its origin is anthropogenic.
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1) The GISS model (using an adjusted climate sensitivity of 0.67 degK per watt/m2) produces a net radiation flux (imbalance) at the top of the atmosphere, increasing approx. linearly during 1965-2003, and now at 0.85 watt/m2 [Fig. 1C of ref 1].. Four points to note:

a) Hansen used different values of climate sensitivity (about 50 % higher) in the past.
b) The model results for global temperature disagree with surface observations, which show a decrease in temperature between 1965 and 1975 [3]
c) The forcings used by the model [Fig. 1A] do not include the cosmic-ray/cloudiness effect of the solar wind [4]; its addition would change the model result significantly.
d) Individual model runs differ greatly [ref 1, Fig.3]; it is not clear if a five-run ensemble is sufficient to produce a stable mean.

2) If this calculated imbalance (in watt/m2), showing a linear trend with time since 1993 [Fig 1C], is reflected in a temperature rise in the deep ocean, then ocean heat content (i.e., the cumulative imbalance in watt-yr/m2) should increase approx. with (time)2 -- but instead, the increase shown appears to be linear [Fig. 2].

3) The detailed comparison [Fig, 3] between observations and model runs is not impressive - even when averaged over a decade. Further, the claimed agreement [Fig. 2] is invalid both temporally and geographically: There was no change in heat storage in the tropics between 1992 and mid-1999; the increase there spanned only 4 years [ref 2, Fig 8]. Also, the rate of ocean heat storage fluctuates and has been both positive and negative since 1960 [ref 2, Fig 12; ref 5, Fig.2]; this variability is not reflected by the GISS model [Fig. 1C].

4) Further, any change in oceanic heat content must derive from a change in sea-surface temperature (SST). Thus the observed SST warming, esp. between 1920 and 1940, should have led to a change in deep-ocean heat storage. But Fig. 1C shows no such corresponding energy imbalance. Do only anthropogenic temperature changes produce an imbalance or change in heat storage? And conversely, is an increase in heat storage necessarily a signal of AGW?

5) An additional claim is that "thermal inertia" of the climate system will lead to a further warming of 0.6 degC over a period of some decades ("the warming is in the pipeline") -- even if GH-gas levels are stabilized [1,6,7]. But such a "thermal inertia" should act as a low-pass filter and smooth out interannual fluctuations of climate; there is no evidence of this in the record. Anyway, the concept is based on the assumption of positive climate feedback and on outdated models of slow diffusion of heat into the deep ocean [8], no longer supported by observations [2,9]. The finding of a negative feedback, derived from analyzing the temperature effects of the Pinatubo eruption [10], leads to time constants measured in months not decades,

6) A final point: Before drawing conclusions about AGW, one should consider that tropospheric temperature trends show no increase with altitude and are even negative, as opposed to all major models, which call for positive trends that increase with altitude [11]. This disparity argues strongly against appreciable AGW during the past quarter-century and further supports the finding of a negative climate feedback in the atmosphere and low thermal inertia in the ocean.
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References and Notes

1. Hansen, J. et al. Earth's Energy Imbalance: Confirmation and Implications. Science 308, 1431-1435. 3 June 2005; online 28 April 2005, 10.1126/science.1110252. In a news release, Hansen stated: "This energy imbalance is the 'smoking gun' [for anthropogenic global warming] that we have been looking for." < http://msnbc.msn.com/id/7665636/ >

2. Willis, J.K., D. Roemmich, and B. Cornuelle. Interannual Variability in Upper Ocean Heat Content, Temperature, and Thermosterisc Expansion on Global Scales. J Geophys Res 109, C12036, doi:10.1029/2003/JC002260.2004

3. Hansen, J. and S. Lebedeff. Global Trends of Measured Surface Air Temperature. J. Geophys. Res.92, 13345-72, 1987

4. de Jager, C. Solar Forcing of Climate: 1. Solar Variability. Space Science Rev 2005 (in print)

5. Pielke R.A., Sr. Heat Storage Within the Earth System. Bull Am Met Soc 84, 331-335. March 2003. doi: 10.1175/BAMS-84-3-331

6 Wigley, T.M.L. The Climate Change Commitment. Science 307, 1766-1769. 18 March 2005

7. Meehl G. et al. How Much More Global Warming and Sea Level Rise? Science 307, 1769-1772. 18 March 2005

8. Hansen, J. et al. Climate Response Times: Dependence on Climate Sensitivity and Ocean Mixing. Science 229, 857-859, 30 Aug. 1985.

9. Schmitt, R.W. et al. Enhanced Diapycnal Mixing by Salt Fingers in the Thermocline of the Tropical Atlantic. Science 308, 685-688, 29 April 2005. See also
Merrifield, B. Ocean Mixing in 10 Steps. Science 308, 641-642. 29 April 2005

10. Douglass D.H. and R.S. Knox. Climate Forcing by the Eruption of Mount Pinatubo. Geophys Res Lett 32 doi:10.1029/2004GL022119, 2005

11. Douglass, D.H., B. D. Pearson, and S. F. Singer. Altitude Dependence of Atmospheric Temperature Trends: Climate Models versus Observations. Geophys. Res. Letters 31, (09 July 2004), L13208, 10.1029/2004GL020103
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I thank David Douglass, Douglas Hoyt, Robert Knox, and Willie Soon for helpful discussion. This research was supported solely by private donations.