Through a roundtable discussion, this paper focuses on the notions of ‘time’ and ‘temporality ’ of nuclear waste, as well as the different time horizons implied by practitioners of nuclear waste storage. In doing so, the paper develops understandings of a key problem defining nuclear waste storage in C21: namely, how to communicate information and memory over the 100,000 years that highly radioactive nuclear matter remains a threat to organic life? This question is notable not least because it involves the proposition of communicating with ‘deep time’ future scenarios in which contemporary representational systems are ineffectual, and even the existence of the ‘human’ is in doubt. The practitioners and researchers in this discussion facilitate understandings of this problem through a number of critical matters of concern for the social sciences – from environmental semiosis, speculative philosophy, post-humanism, new materialism, nuclear semiotics, landscape art and aesthetics, future literacy, to nuclear waste at a regulatory level. Distinctly, the discussion advances not only how environmental things might help establish allies in the communication across vast time scales, but also considers the aesthetic techniques for imagining untimely modes of future-thinking that remain open to recuperation today – including through geo-ontological modes of thought, ecosemiotics, or the associated powers of nuclear environments to mobilize forces of aesthetic expression.