SCOSTEP is tasked to organize organize long-term scientific programs in solar terrestrial physics. The program for 2020-2024 is Variability and Predictability of the Solar-Terrestrial Coupling (PRESTO). PRESTO was defined based on a community effort with numerous white papers submitted to the Committee for Definition of the Next Scientific Program (NSP) and two fora organized by the International Space Science Institute (ISSI) in Beijing in 2018 and in Bern in February 2019. PRESTO's goals are to "address the predictability of 1) space weather on timescales from seconds to days and months, including processes at the Sun, in the heliosphere and in the Earth’s magnetosphere, ionosphere and atmosphere, [and] 2) sub-seasonal to decadal and centennial variability of the Sun-Earth system, with a special focus on climate impacts and a link to the World Climate Research Program (WCRP) Grand Challenge Near-Term Climate Predictions as well as the IPCC." (NSP Concept Text).