There is a comforting logic in informing people before encouraging them to act. Take smoking. We may need to reframe the message depending on the person and what we suspect motivates them (“it’s like kissing an ashtray” or “non-smokers are more likely to meet their grandchildren”) but, as Muir Gray reminds us, ignorance is probably the most important cause of disease.

Which brings us to climate change; an area where it’s convenient (for all of us) to deny or minimise the risk. Just like the tobacco story some years ago: it’s not that we were unaware that smoking causes ill health: it’s just that we weren’t good at communicating the scale of the health risk. Half all smokers die prematurely because they smoke. That’s Russian Roulette with three barrels filled. As for climate change, we are nowhere near quantifying and communicating the risk clearly yet. It’s a more difficult issue than tobacco: in fact it’s overwhelming. Something that is everyone’s business is too often no-one’s business. Some doctors do not know the risk of climate change. Some doctors do know, and work tirelessly to remind colleagues and others that we have a duty of care to act for the future. What is puzzling is that there are plenty of clever and committed health professionals who do know the risk of taking no action on climate change and don’t appear to care. That’s a really difficult one to understand, let alone communicate…