B. Why?

The IPCC was formed to combat global pollution.  It was not formed to determine global cooling or warming. (See data from Question 1)  The IPCC’s organizational documents identify its purpose, i.e. to fight man made pollution on a global scale. [Hester R., Harrison, R, (2002) Global Environmental Change , Royal Society of Chemistry, Thomas Graham House, Cambridge, UK, ISBN 0-85404-280-6, ISSN 1350-7583.]

It was agreed at the first meeting of the IPCC that a new assessment of the whole issue of anthropogenic climate change should be prepared.” (IPCC 1990 pg. 3)

Anthropogenic means environmental pollution and pollutants originating by human activity. [Google™ Dictionary.] 

“The Climate Change that we are addressing is the result of human activities.” (IPCC 1990 pg. xxxvi). 

The IPCC’s “primary audience” was “governments and policy makers.”  [IPCC (2011) Report of the 33rd Session of the IPCC. May 2011, Abu Dhabi. Decisions Taken with Respect to the Review of IPCC Processes and Procedures; at page 32.] 

The IPCC wrote a “Guidance Note for Lead Authors” on how to write persuasive reports.  [IPCC (2010) Guidance Note for Lead Authors of the IPCC 5th Assessment Report on Consistent Treatment of Uncertainties. IPCC Cross-Working Group Meeting on Consistent Treatment of Uncertainties, July 2010, Jasper Ridge, CA.]

IPCC members are encouraged to undergo media training. [IPCC (2012) Report of the 35th Session of the IPCC. June 2012, Geneva at pg. 39.]

The authors are to use emotions (climate consequences) and classified with “high certainty” whenever the probability is low. [See Guidance Note for Lead Authors cited above]  Hence, the formation of the IPCC appears to have a connection to Politics.