I'm pretty sure you typed that wrong. If what you meant to say was "Please explain why you are sure that the cessation of the ice age, with an accompanying moderation in temperature, is what permitted human agriculture [This is the assertion he makes, that consistent temperatures allowed/was favorable for farming] -- and not the reverse. [Are you suggesting that farming permitted the cessation of the ice age and moderation in temperatures?] Please describe an experiment to falsify your premise." I might be able to help with an experiment to test if moderation in temperature helped facilitate farming; otherwise please clarify what you are asking.
To the possible suggestion that human farming could have ended the ice age and moderated temperatures I can only suggest you go try and farm on a glacier and see how that works out. After you have sufficiently tested the farming on ice theory for the melting of glaciers and cessation of the ice age I believe we could create an experiment to test if consistent environmental conditions are conducive to more productive farming (and thus more favorable to cities and civilization).
First create an artificial controlled environment (Control) that exactly matches the conditions in a designated location (that has successfully maintained farming for an extended period of time) while removing variables such as pollution, vandalism, and other external hazards that would not effect the other environments.
At the same time we will create another artificial controlled environment (Variable) where the weather conditions will randomly selected (in a way to still coincide with the seasons, and within reasonable limits of annual extremes over the past 8,000-10,000 years) from year to year. The first year will be identical to the first year in the control environment with random selection beginning in year 2. This won't perfectly replicate long term variations (and the effects) in environment but should sufficiently test the effect of variability of environment on agriculture.
I propose one more artificial controlled environment (Constant) that has perfectly predictable weather conditions from year to year. Thus all years will have the same conditions as the first year of the control.
Further we can measure the performance of these environments in relation to the selected location to further control for possible unforeseen factors and for comparison to real world conditions.
The environment to have produced the greatest yields with the lowest costs/losses over an extended period (say 20-40 years) will be deemed the most successful and conducive to agriculture.
If you are proposing that cities and civilization either arose independently of agriculture or facilitated agriculture (instead of agriculture facilitating cities/civilization) our conversation is over and I would refer you to the extensive studies of early human civilization.