According to a new Nature article (which this AP story does not link to directly), at 1.5 degrees Celsius of warming,

An international team of scientists looked at 16 climate tipping points — when a warming side effect is irreversible, self-perpetuating and major — and calculated rough temperature thresholds at which they are triggered. None of them are considered likely at current temperatures, though a few are possible. But with only a few more tenths of a degree of warming from now, at 1.5 degrees Celsius (2.7 degrees Fahrenheit) warming since pre-industrial times, four move into the likely range, according to a study in Thursday’s journal Science.

AP

The coral reefs will affect fishermen around the world in the very near future. The others, even though they are irreversible, may play out slowly even over centuries, according to the article.