The action required to stem the environmental and social implications of climate change depends crucially on how humankind shapes technology, economy, lifestyle and policy. With transport CO 2 emissions accounting for about a quarter of the total, we examine the contribution of CO 2 output by scientific travel. Thankfully for the reputation of the scientific community, CO 2 emissions associated with the trips required to present a paper at a scientific conference account for just 0.003% of the yearly total. However, with CO 2 emissions for a single conference trip amounting to 7% of an average individual’s total CO 2 emissions, scientists should lead by example by demonstrating leadership in addressing the issue.