Joao Teixeira Jet Propulsion Laboratory Turbulence and convection in the atmosphere and ocean are at the core of key climate prediction problems. For example, 1) the cloud-climate feedback (how clouds will respond to climate change, and in turn will impact climate) is essentially a problem concerning the interactions of a highly turbulent flow with water phase transitions and radiation; 2) The extreme weather and climate change problem is essentially about how moist convection will respond to a warmer world. Most of these turbulent and convective processes are not resolved explicitly in climate models: the grid-resolutions are too coarse. However, these small-scale sub-grid processes (turbulence, convection, clouds) play a key role in regulating the large-scale climate. This presentation will focus on a key issue: how to represent in an integrated manner, sub-grid scale turbulent and convective mixing in climate models. Modern unified approaches to model turbulence and convection involving optimal combinations of eddy-diffusivity and mass-flux (EDMF) methods will be discussed in detail. We will also describe a Large-Eddy Simulation (LES) model developed at JPL/Caltech to help design these new unified methods. Finally, the impact of these new EDMF approaches when implemented in climate models will illustrate the key role that turbulence plays in the overall climate system.