It seems several times, in 2004 especially, there were long edit wars and of course WC was involved, to remove any mention of theory from the global warming page. Even the greenhouse theory was removed. Even the article about the originator of the theory, Arrhenius, had the word theory removed.
In 1896 he published a long memoir “On the Influence of Carbonic Acid in the Air Upon the Temperature of the Ground,” in which he developed a theory for the explanation of the glacial periods and other great climatic changes, based on the ability of carbon dioxide to absorb the infrared radiation emitted from the earth’s surface. Although the theory was based on thorough calculations, it won no recognition from geologists. In 1898 Arrhenius wrote a remarkable paper on the action of cosmic influence on physiological processes.
Fixedreference, a web site with copies of Wikipedia fixed in time, has a copy of the Global Warming article before the word theory was removed from it.