Faced with the threat of a “post-truth” world and a widening chasm of exchange between climate change deniers and environmentalists, I argue that future-orientated literary and media speculative fictions—which I term “speculative futures”—offer a means of building lines of communication across social and political divisions. This thought piece on “The Environmental Humanities in a Post-Truth World” mediates upon the potentiality of speculative futures as theory, social bridge-building, and pedagogical tool. Speculative fictions (especially those that address environmental justice, and anti-colonial and feminist politics) use storytelling and future imaginaries to challenge political falsehoods and imagine more ecological, de-colonized futures