catastrophic是什么意思？

Many experts now believe that given the right policies, the effects, though grave, need not be catastrophic.

Unless renewables become cheap enough that substantial carbon deposits are left underground for a very long time, if not forever, the planet will likely be exposed to potentially catastrophic climate risks.

While alternative estimates of the damage from carbon emissions differ, and it's especially hard to reckon the likely costs of possible catastrophic climate events, most estimates suggest substantial negative effects.