Ocean, ice, and climate: the slow dance of a complex system

The time horizon of global change is on scales of years, decades, centuries, and beyond, and this variability can have a tremendous regional impact. The importance of the oceans and cryosphere in climate change increases with time scale because of their large thermal inertia. NASA's Earth Science Enterprise has developed a research strategy to address climate relevant questions about the ocean and cryosphere, such as: how is the global ocean circulation varying on interannual, decadal, and longer time scales?; and what changes are occurring in the mass of the Earth's ice cover? This strategy starts with basic exploration utilizing satellite measurements, leads to improved understanding by incorporating data and models, and ends with improved prediction and benefit for the future. In this paper we consider the science and technology challenges for the ocean and cryosphere strategy over the next twenty-five years.