OptCliM investigated climate modelling advances from mathematical optimization research. Our focus was upon parameterised processes that represent physics that are unresolved within climate models. These unresolved processes were represented through equations that include fixed parameters, with a typical climate model having around a hundred parameters. For example, thunderstorms not only generate heavy rain but are also one route for moisture into the atmosphere. One of the parameters expressed the rate at which moist air in the storm is mixed into the atmosphere. A range of values for each parameter was consistent with theory and measurement with changes in some parameters having a dramatic effect on future climate predictions. It was therefore necessary to have realistic parameter values in order to adequately model past or future climates.