Domain Atmospheric Description The ECV "Other long-lived greenhouse gases" refers to a set of gases additional to carbon dioxide and methane that are classified as having atmospheric lifetimes of at least a few years. The term "well-mixed" is also used to characterise them and may be preferred. Stratospheric distributions of these species may nevertheless exhibit quite substantial spatial variations, either because of the multi-year time scale of much of the transport and mixing across the region or because of localized photochemical reactions. It is important to measure this set of gases because some already contribute appreciably to the radiative forcing of climate change due to increases in concentration since the pre-industrial era, whilst others are increasing rapidly in concentration and have a strong potential to enhance warming if their emission continues unchecked. Some also have to be monitored because they deplete ozone in the stratosphere. This has to continue for the species that are subject to emission controls under the Montreal Protocol, as their lifetimes are long.