In his letter of June 2011, Mr Cummings asked the following question:-
Could the CSIRO please cite the reference to a published peer reviewed climate research paper that provides observational data, which clearly shows the global hydrological cycle slows down (i.e. the period lengthens) as global temperature increases?
In his response dated 8th August 2011, but not received and re-sent on 1st November 2011, Senator The Hon Kim Carr, then Minister for Innovation, Industry, Science & Research included a response by the CSIRO (see final paragraph).
The CSIRO stated that they are "...unable to provide a reference as requested."
The CSIRO also made the following assertion: "CSIRO has not asserted that the global hydrological cycle is slowing down as global temperatures increase."
However, The Hon Greg Combet MP, Minister for Climate Change and Energy Efficiency in his letter of August 2012 (see second dot point) has since stated that the global climate models previously increased virtual evaporation by only 4% for each 1-degree increase in temperature.
The global climate models managed by the CSIRO have to slow down the virtual global hydrological cycle, or virtual evaporation will increase by at least 7% for each 1-degree increase in temperature. This would have the effect of limiting predicted increases in surface temperature for a mooted doubling of atmospheric carbon dioxide to less than 1-degree.
It would appear therefore that the above assertion by the CSIRO was incorrect and mendacious.