Trenberth argues that since science / physics has already established the human influence on climate, oceans, etc. (and Curry would not say otherwise) it makes more sense for Curry to have to show that there is no influence on water vapor and precipitation (i.e., intensification of
storm activity /
heavy precipitation) than to show that there is, because of basic physics / physical systems / physical relationships that constitute the global climate cycle.
· In the mid - and high - latitudes of the Northern Hemisphere over the latter half of the twentieth century, it is likely that there has been a 2 to 4 percent increase in the frequency of
heavy precipitation events [thunderstorms and large - scale
storm activity].