‘Threshold’ was an exhibition of environmentally engaged art held in the Michaelis Gallery in October 2011, curated by Michaelis senior lecturer Virginia MacKenny as part of her 2011 Donald Gordon Creative Arts Award. It responded, in part, to the most pressing concern of our time: that of climate change. As its title suggests, the exhibition engaged the premise that not only are the climatic conditions of the planet at a tipping point, but that we need to renegotiate our relationship to the planet, this place we call home. The exhibition was thus as much to do with perception and the garnering of visual acuity and observation in the process of witnessing, as it was with environmental awareness. Encouraging our ability to notice and be attentive to both optical and conceptual perceptions better equips us to actively embody our custodianship of the planet.