Email, John Nielsen-Gammon, Texas state climatologist, Regents professor, Texas A&M University, Dec. 6, 2013

On Dec 3, 2013, at 4:36 PM, Selby, Gardner (CMG-Austin) wrote:

Dr. Nielsen-Gammon:

 

Hello again.

 

I am lately checking a claim by candidate Barry Smitherman that the Earth isn't warming. I'm told he based his conclusion on the sources I am pasting below.

 

Is he right that the Earth is, in fact, not warming? If so, why? If not, why not?

 

Feel free to call instead?

 

Thanks.

 

g.

 

W. Gardner Selby

 

PolitiFact Texas

4:53 p.m.

Dec. 6, 2013

Gardner -

   The Earth is warming.  The Earth can gain and store heat in the atmosphere, in the top part of the land surface, and in the ocean.  Of those three heat reservoirs, the largest changes by far take place in the ocean, which has been warming quite rapidly since 1995 and more slowly since the 1970s.  See, for example, figure #2 at http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

   However, global surface temperatures have risen more slowly in the past 15 or so years than they had during the previous 35, and it is possible to find time intervals (such as the past five years) in which all weather station and satellite-based global temperature compilations show a declining trend.  Overall, the global surface temperature trend is essentially flat since the dramatic and unusual warmth of the 1998 El Niño year.

   Just about everyone, including some of the sources quoted in the articles you listed, believes that the present lack of surface temperature warming is both natural and temporary.  Climate model projections have generally been higher than observed temperatures, which depending on your interpretation means that natural variability has temporarily masked some of the warming or that the models have overestimated the amount of non-natural warming.  The causes of the discrepancy are the subject of considerable research.

    - John