Human-caused climate change is a global emergency, and its harms are predicted to increase exponentially in the coming years, particularly if unsustainable practices continue unmitigated. Adverse effects of climate change on communities affected by or at risk for cancer, such as frail older adults, are already measurable and deadly. If nurse scientists continue to ignore these realities, more people are likely to suffer and die as a result. The purpose of this critical reflection is to discuss the vital necessity of including climate change in the research agenda of the Oncology Nursing Society and all nursing science. Using an approach grounded in critical theory and design justice, the authors provide specific suggestions for the incorporation of scientific considerations and nursing measures related to climate change into oncology nursing science.