Far from being laggards in mitigating climate change, health professionals should be leaders. They have scientific training, which means they are better able than many to understand the science that underpins climate change. They are more trusted than any other group, particularly after the bravery they have shown in countering the pandemic, and they interact with millions of citizens every day. Then the threat to health and the positive benefits to health from a low carbon life is probably the best way for citizens to be motivated to act on climate change. In many countries, health workers outnumber and other groups of employees, and the actions they and their families take as individuals can have a sizeable impact—and they provide leadership by example. Finally, health professionals have global networks, and mitigating climate change demands global action.