Ocean Heat Content – EPA Uses Computer Projections Rather Than Observed Data

Despite the fact that observed ocean heat content has not increased since 2002,  the EPA used computer projected ocean heat content to justify their Greenhouse Gas Finding.

The EPA published their response to comments in their Endangerment and Cause or Contribute Finding for Greenhouse Gases under the Clean Air Act.  The comments were solicited by the EPA as part as their “deliberation” .  By now you probably know that the  EPA found that greenhouse gases are a threat saying:

Endangerment Finding: The Administrator finds that the current and projected concentrations of the six key well-mixed greenhouse gases–carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6)–in the atmosphere threaten the public health and welfare of current and future generations.

With regard to comments about ocean heat content,   the EPA responded with this:

Several commenters (3187.4, 7031, 9877) argue that the recent plateau in ocean heat content (from 2003 to 2008) suggests anthropogenic warming is not occurring because it indicates that the climate system is not accumulating heat. The lack of heat accumulation, they state, demonstrates a failure of the anthropogenic global warming hypothesis to account for natural climate variability, especially as it relates to ocean cycles. They claim that the recent trends in ocean heat content suggest the Earth’s energy budget is not out of balance owing to GHGs, in contrast to the findings of Hansen et al. (2005).

Though the commenters refer to a recent plateau in ocean heat content, there are published papers which find the opposite, as mentioned in Volume 2 of the Response to Comments document. In fact, this work (von Schuckmann et al., 2009) indicates the global ocean accumulated (between the surface and 2,000 meter depth) 0.77 (plus or minus 0.11) watts per square meter of heat between 2003 and 2008, which is roughly consistent with the 0.86 (plus or minus 0.12) watts per square meter of heat (between the surface and 750 meter depth) accumulated between 1993 and 2003 as documented in Willis et al. (2004); and Hansen et al. (2005). These studies suggest the ocean has and continues to accumulate heat, contributing to an overall imbalance in the Earth’s energy budget, as further documented in two other recent studies by Trenberth et al. (2009) analyzing the period March 2000 to May 2004 and Murphy et al. (2009) (analyzing the period 1950–2004).

We have added the following text on this topic to Section 4(f) of the final TSD on this topic:

The thermal expansion of sea water is an indicator of increasing ocean heat content. Ocean heat content is also a critical variable for detecting the effects of the observed increase in GHGs in the Earth’s atmosphere and for resolving the Earth’s overall energy balance (Bindoff et al., 2007). For the period 1955 to 2005, Bindoff et al. (2007) analyze multiple time series of ocean heat content and find an overall increase, while noting interannual and inter-decadal variations. NOAA’s report State of the Climate in 2008 (Peterson and Baringer, 2009), which incorporates data through 2008, finds “large” increases in global ocean heat content since the 1950s and notes that over the last several years, ocean heat content has reached consistently higher values than for all prior times in the record.

Thus, the TSD’s summary of the current state of the science on ocean heat content as reflected in the underlying assessment literature is reasonable and sound.

Roger Pielke, Sr, responds to the EPA by noting that the observed temperatures show no increase in ocean heat content and that the EPA’s relied on  Jim Hansen’s computer predictions of ocean heat content to arrive at their conclusions.

The observed accumulation of heat content using the baseline of  end of year 2002 is as follows


Year Joules
2003 0
2004 0
2005 0
2006 0
2007 0
2008 0
2009  (estimated) 0


Year 10^22 Joules
2003 0.98
2004 1.96
2005 2.94
2006 3.92
2007 4.90
2008 5.88
2009 6.86
2010 7.84
2011 8.82
2012 9.80

(The end of year 2002 as a baseline is significant in that 3000 Argo Buoy were in place in 2003 measuring ocean temperature and salinity.)

Pielke points out that :

Thus, according to the GISS model predictions, there should be approximately 6.86 * 10**22 Joules more heat in the upper 700 meters of the global ocean at the end of 2009 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 three years. This requires a heating rate over the next 3 years into the upper 700 meters of the ocean of 3.27* 10**22 Joules per year, which corresponds to a radiative imbalance of ~+2.0 Watts per square meter.

Pielke adds that:

The EPA failed to discuss this discrepancy between observations and the model predictions. Despite what they wrote, the climate system, as represented by the upper ocean heat content, has not been accumulating heat over the last 6 years or so.

To read all of Pielke’s posting ,   click here

for other postings on ocean heat content

Ocean Heat Content


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