Recent Ocean Heat Content Trend Shows Lack of Heating

J. M. Lyman and colleagues earlier this year claimed the ocean heat content data of 1993 to 2008 showed a global warming trend of 0.63 +- 0.28 W/sq.m.  They allowed that the rise from 1993 to 2000 was followed by a flattening ocean temperature that started about 2001-2002.  Given a peak in land surface temperatures around 1998 and a subsequent flattening for a few years after that as solar irradiance and sunspot activity moved out of a warm cycle into what is looking more and more like a cooling cycle, it is to be expected that the ocean heat content would rise for a few years following the end of the solar irradiance increases.  As Roger Pielke Sr.has pointed out, the oceans hold 90% of the variable heat content of the Earth in the upper ocean water.  Thus, trends in the upper ocean temperatures and its heat content must be related to the solar radiance, though with a bit of lag and some averaging due to the huge heat capacity of the ocean.

With respect to longer term trends in the Earth's climate, the upper ocean temperatures are a much better measure than the flighty atmospheric temperatures on land, which are influenced much more by the time of day and the nearby human population.  We know the ground-based weather stations to have been badly biased upward by urban heat island effects (here, here, here, and here) and a long period of undocumented data manipulation (here and here and here).

R. S. Knox and D. H. Douglass of the Department of Physics and Astronomy of the University of Rochester have an in press publication in the International Journal of Geosciences, which uses data from the global array of Argo floats to calculate the ocean heat content (OHC) of the upper oceans.  The Argo floats were deployed in the early 2000s and are less prone to the biases and errors of the expendable bathythermographs used to obtain earlier ocean data.  The data is show in the graph below:

The green line shows the average annual ocean surface temperature provided by the Climate Research Unit at the University of East Anglia.  That has been trending downward since 2003, with most of the drop since 2005.  The Argo data from the surface to a depth of 700 meters is plotted in blue.  The red data points are the 12-month moving average of the blue line data.  The dashed red line is the linear fit to the 12-month moving average data.  The energy flux to compare to the Lyman result of 0.63 +- 0.28 W/sq. meter increase is -0.161 +- 0.040 W/sq. meter.

The result does not indicate the expected large rate of increase in OHC due to a warming planet if the increasing concentration of CO2 in our atmosphere were the primary driving force in our climate and it acted as the climate models have generally claimed it does.  Given the short span of time and the strong annual variations of the OHC, this result does not clearly rule out a warming effect of CO2 upon the Earth's temperature.  But, it does suggest that the cooling expected by many solar scientists due to decreased sunspot activity, may have started.  It argues that it is foolish to believe that the warming trend of the 1980s and 1990s was the early part of a catastrophe, which was caused by increasing concentrations of atmospheric CO2.  It argues that we need to continue to carefully observe solar effects and the ocean heat content so that we can come to a real understanding of our climate and what causes longer term changes in it.

It also follows that forcing the world's peoples to do without energy or to pay skyrocketing costs for renewable energy or carbon sequestration on the basis of an ensuing catastrophe caused by man-made CO2 emissions is without justification.  It is terribly wrongheaded to use force to make people give up many of the comforts of their lives because some scientists and politicians have been claiming an unproved hypothesis is established fact.  Far from it, the strong global warming claim based on atmospheric CO2 has a trendline which indicates that it is not likely to make the transition from hypothesis to proven theory!