The study reports the author's innovation of teaching climate education to adult learners in an English class using project-based learning (PBL). Over a whole semester in 2022, six topics related to climate change were taught and learned in a core curriculum tertiary English class in China. At the end of the semester, data showed a high level of English language learning achievements indicating the benefits of using problem-based learning with adults. Data collected from an online discussion forum and subsequent learner interviews show that climate education included within an English class does encourage learners to pay much closer attention to a number of dimensions of the social issue of climate change, and indicates learner willingness to act to combat climate change.