Iceland as a heat island

Iceland is a strong localized source of non‐eruptive volcanic warming and cooling. Temperature trend maps show that this phenomenon is localized to an area of about twice that of Iceland. With altitude the area remains constant but the phenomenon weakens and changes sign upon passing through the tropopause. The effect's magnitude implies a large positive feedback, according to a conventional climate forcing estimate. This phenomenon is unique in that it is not observed for the other major volcanic islands.