Rainfall is already on the increase by the way (and this summer can testify, with record amount of rain here and there). One point that is not discussed to my knowledge is the study of warm rain in the Arctic. This study only cover the question of snow melting before reaching surface, which obviously is the biggest factor. But given the ongoing trend toward stronger shallow convection, and soundings like this one during the rain event of the 23rd and 24th of August, the question of warm rain microphysic could be asked.