The triple threat of changing climate, loss of biodiversity and pollution poses a significant challenge to our patients and the planet, and healthcare contributes to all three elements of the threat. The carbon footprint of continued professional development (CPD) is increasingly recognised, although a cognitive dissonance exists whereby climate change is acknowledged but air travel to conferences continues unabated. A CO allowance for CPD activities has been suggested previously. We suggest that CO footprint estimates could be incorporated into existing CPD diaries as a step towards visualising the environmental impact of CPD. Electronic CPD diaries are already widely used and typically contain dates and locations for CPD activities. It would be relatively easy and inexpensive to add an estimate of CO footprint to these diaries. Such an approach would initiate reflection, promote insight and help facilitate behavioural change. We call on institutions involved in CPD licensing, administration and documentation to trial this approach and share their experience.