Friday, October 31, 2014

New excuse #57 for the "pause" of global warming: Increase in mid- and upper level clouds

Via email from climate data analyst John McLean of the Dept. of Physics, James Cook University, Australia, comes explanation #57 for the global warming "pause," related to an "increase in mid- and upper level clouds" after 1997, which increased albedo/reflection of sunlight.

McLean also finds that "CO2 played little if any part" in the post-1950 global warming, which the IPCC attributes with alleged "95% confidence" entirely to man-made greenhouse gases. He instead finds post-1950 warming explained by natural shifts in ENSO and cloud cover. As he notes, "This means that there is little if any "missing heat" that (supposedly but improbably) 16 years ago decided to start hiding itself away where no-one could find it."

Email from John McLean [emphasis added, h/t Marc Morano/Climate Depot]:

My new paper about late 20th century warming is now available via

I show that the pattern of global average temperature anomalies since 1950 can be described as a sequence of:

(a)  ENSO shifting from lots of La Nina events and very few El Ninos to the opposite situation
(b) from 1988 to 1997 a reduction in the total cloud cover anomaly
(c) after 1997 a decrease in low level cloud but an increase in mid and upper level cloud

The temperature data is HadCRUT4, the ENSO data the Troup data from Australia's Bureau of Meteorology and the cloud cover data the D2 dataset from ISCCP.

Of the above it was (b) that caused warming of about 0.45C degrees.  When I adjusted the data in the often-quoted energy balance diagram by Trenberth et al, I found that the increase in heat absorbed at the Earth's surface was about 5 watts per square metre, a figure greater than that given by the IPCC 5AR for the extra heat caused by greenhouse gas emissions.

If my hypothesis is correct then CO2 played little if any part.  This means that there is little if any "missing heat" that (supposedly but improbably) 16 years ago decided to start hiding itself  away where no-one could find it.

The paper is being discussed on WUWT:

and on Bishop Hill:


  1. Hope you get to #58 quickly. You now have "57 Varieties" of the pause, a phrase that is a registered trademark of Heinz. This great brand would not want to be associated with a list of excuses.

    1. The count is already up to 65...

  2. Another related cause for warming then pausing temperatures is when it warms over any body of water, the water molecules get agitated. As the water is agitated, it results in evaporation at levels corresponding to the increase in temperature. Then cloud cover thus increases reversing the trend of temperatures.