It's kind of like that. In three ways that I can think of. The models are run hundreds or thousands of times across different countries. The climate, modelled o

It's kind of like that. In three ways that I can think of. The models are run hundreds or thousands of times across different countries. The climate, modelled on a day by day basis, is effectively random for any particular instant. And the input variables, where they do change even minutely, act like seeds in a random number generator. It's not so much a glorified Excel spreadsheet as it is having thousands of Excel spreadsheets, each dependent on the one before and a slightly different scenario that's different for every set of these Excel sheets. They are running these on super-computers many many times over and would have no interest in doing exactly the same thing over and over. http://www.climatechange2013.org/images/report/WG1AR5_Chapter09_FINAL.pdf http://www.climatechange2013.org/images/report/WG1AR5_Chapte... And yes, they even mention the 15 year hiatus - they don't sweep this under the rug like so many have taken to believing they do. In fact, it's mentioned throughout the AR5. In fact, you can get a sense of them being just eager to tackle it in substantial detail - it's wonderful.