A climate extreme (i.e., an extreme weather or climate event) occurs when the value of a weather or climate variable is above (or below) a threshold value near the upper (or lower) end of the range of observed values of the variable. For simplicity, both extreme weather events and extreme climate events tend to be referred to collectively as “climate extremes” (IPCC, 2014b, annex II). Risk is constructed by summing rankings for vulnerability and exposure to climate change and the number of weather-related events.