This essay argues that the way Lord Byron’s poetry takes up the common yet problematic distinction between ‘natural’ and ‘human’ catastrophes points towards something fundamental in his work and beyond. Discussing Don Juan in detail, I show how Byron insists that the very idea of the distinction between a ‘natural’ and a ‘human’ catastrophe is extremely destructive and, ultimately, life-threatening. While he is very sharp in his criticism, Byron also offers potential conceptual and poetic relief to this insight, especially through his use of poetic wit and humour. He maintains this strategy throughout his oeuvre with one notable and, I argue, central exception. In his poem ‘Darkness’, he refuses to employ the typically Byronic mode of aestheticisation or distancing. This poem ends up imagining a catastrophe that goes beyond the possibility of rationalisation. It thereby reveals a dark counter-point not only regarding Byron and the subject of catastrophe in his work, but also his work as a whole. In order to develop convincing poetic wit or aesthetic form, Byron needs to articulate the real possibility of total, nonrecuperable disaster.