(archaeology, paleontology) The process by which individuals in a population die off in large numbers as part of a single event (rather than one by one, from a variety of causes).

(ornithology) A moult, typically in penguins, in which most or all of the feathers are shed at the same time / (zoology) A similar process in some seals in which large areas of skin are lost

The severe negative effects of climate change on both the natural world and humanity as a result of extreme weather events, sea level rise, biodiversity loss, etc.