The past 15 years have seen CO2-switchable materials move from a minor footnote to the forefront of stimuli-responsive materials research. New functional groups, applications, switchable properties, and switching chemistries are being published every year. But behind the excitement there are many unanswered questions, ranging from basic physical chemistry all the way to the environmental consequences of future commercial applications. There are also potential technical challenges to explore – challenges which may turn out to be real or only imagined and may or may not be overcome by research. Development and commercialization of CO2-switchable materials are generally in the very early stages, although switchable draw solutes for forward osmosis are the closest to market. The environmental impacts of switchable materials are anticipated to be lower than those of competing nonswitchable materials but more evidence is needed.