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Thursday, October 3, 2013

What is Actually "in the Pipeline"?

Now that the concern of the month is rising Ocean Heat Content (OHC) the focus has inadvertently turned to "in the pipeline" warming.  Whenever there is warming or cooling at the surface there has to be an energy imbalance with the oceans.  The atmosphere is a fast response, say months to years of lag, the ocean atmosphere interface or boundary layer is longer, years to decades of lag depending on how well things are mixed and the deeper ocean more like centuries to thousands of years.  With the new ARGO 0-2000 meter ocean data indicating an increase of about 0.08 C since the 1950s, which is around 2.6 x 10^23 Joules.  That would imply about 0.015C per decade or 0.15C per century.  There is some indication of acceleration, but the margins of error measuring that small of a temperature change leave a lot to be desired.  So as a rough guess let's say about twice that or 0.3C per century putting us in the ballpark of 300 years for 0.9C of deep ocean, 0-2000 meter, temperature change.  If nothing changed, whatever energy imbalance there is would decay to zero over about 300 years.   Since there was a little ice age prior to this current warming, how do you figure out what is due to what?

The dT(CO2)x above is based on x*ln(CO2/280)/ln(2) using the BEST CO2 interpolation to 1958 and the Mauna Loa CO2 data from 1958 to present.  GISS (Goddard Institute of Space Studies) Global land and ocean data and the Hadley Climate Research Unit version 4 Global surface temperature data set.

Using CO2 for a stable baseline we can get a reference value based on 280 ppm.  I have fit the GISS and HadCRU4 surface temperature data to this new zero by offsetting HadCRU4 by 0.3C and GISS by 0.38C.  The name of the chart is because there is no consistent baseline.  Even the climate models can't get the average absolute temperature right, so about all we have to work with is CO2 and the assumption that the CO2 levels recorded in Antarctic ice are valid.  Leaf stoma in the NH tends to indicate a little bit higher value than 280, but I will save that for later.

In this time scale, the no feedback "sensitivity" seems to be in the ballpark.  We don't know what is in, or was in, the deep ocean pipeline though. 

This is the same spread sheet with a few changes.  The GISS and HadCru4 are now jan-dec annual anomaly and I have change the 4.5 dT(CO2) to 1.5 for a better fit which a number of papers using energy models have discovered.  The 3C dT(CO2) I have lagged by 32 years.  With the 32 year "in the pipeline" lag there is a pretty fair fit.  As long as you assume there is nothing but CO2 driving climate, you are home free, super simple.

If you don't want to make that assumption you can consider all the data and all the data issues and note that there may be a longer term trend that could force some reconsideration of the simple, obvious cause.

Using the Oppo Indo-Pacific Warm Pool reconstruction as a rough estimate of a secular trend I added that trend to the CO2 references.  There is still a pretty good fit, but at least 0.2C is due to recovery.

By dropping the noisier land portion of the data though, no feedback "sensitivity" appears to make much more sense, compared to the ERSST 60-60 SST and the global 0-700 meter vertical temperature anomaly. The shift required here was 0.35C implying about 0.3 C of the warming could be due to recovery from a little ice age period of close to 0.3C per century. 

Is this the right way to look at the problem?  Dunno, but it never hurts to consider other frames of reference. 

UPDATE: Since some who will remain nameless require more...

Heating the oceans can take a while and the only heat around that long was solar.  CO2 will no doubt add some, but 50 years just ain't long enough to see much impact. 

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