A Historical Case for Methyl Bromide as the Missing Anthropogenic Source in Early 20th Century Warming

Temperatures began to rise in the Arctic atmosphere around 1920 increasing more than 1 �C by the 1940s, slowly returning to the long term historical limits by 1965. This period is referred to as the Early Twentieth Century Warming (ETCW). Many models and theories have been proposed since the 1990s to explain this increase. Radiative forcing from greenhouse gases and natural phenomena from volcanoes, solar cycles, internal variability, etc., have all been included but after over 30 years no matter how much variability is included, there is always the suggestion or conclusion that there must be an additional anthropological source. This remains one of the most important areas of research in climate science. It is the goal of this paper to show through a review of the historical record that these objections can be overcome and that methyl bromide could be the “missing anthropogenic” source that can solve the ETCW mystery.