From the Greek word nephos for 'cloud') is the study of clouds and cloud formation. British meteorologist Luke Howard was a major researcher within this field, establishing a cloud classification system.
 While this branch of meteorology still exists today, the term nephology, or nephologist is rarely used. The term came into use at the end of the nineteenth century, and fell out of common use by the middle of the twentieth. Recently, interest in nephology (if not the name) has surged as many meteorologists have begun to focus on the relationship between clouds and global warming. Some nephologists believe that an increase in global temperature could decrease the thickness and brightness (ability to reflect light energy), which would further increase global temperature.