“There’s a 50% chance that humans will be extinct by the end of the century because of climate change,” said Hugh Montgomery, director of the UCL Institute for Human Health, at last week’s conference on environmental sustainability. I’d heard that before, but it made me think of my daughter, who can expect to live for most of this century. And what about any children she might have? And then I wondered if the apocalyptic vision, true as it might be, is the best way to spur people to act on climate change.

Most people at the conference seemed to agree that it wasn’t. Such a message makes people feel powerless and think “Let’s eat, drink, and be merry because tomorrow …”

The bad news from Montgomery – of crop failure, drought, extinction of other species, economic collapse, mass migration, and war – was countered by the “good news” from Andy Haines, a professor at the London School of Hygiene and Tropical Medicine. A “thought experiment” published in the Lancet showed that if we insulated our homes, cycled more, ate less meat, and generated electricity through solar panels then we would not only slow climate change but also save many deaths from chronic disease. But, I reflected, doesn’t fewer deaths mean more
people – and so more carbon consumption?

The good news message doesn’t quite work either it seems because most people in the NHS are not actively engaged in countering climate change. Only 6000 health professionals have signed the pledge of the Climate and Health Council to act on climate change. Some health professionals have been urging action for 20 years, and I wrote the first BMJ leader on climate change in 1996, saying that we must act. It may be that people in the NHS feel that they are doing enough good already. “I’m busy saving lives. I can’t save the planet as well.”

A group of us at the conference discussed what might be a better way of presenting the message. The first point was that there can’t be one way. Different people will respond to different messages. Perhaps we need to concentrate on the WIFM as it’s known, the “what’s in it for me.” Or maybe we need a range of individual stories of how people have been affected and how people have responded. For many people, perhaps all of us, actions speak louder than words, and Mary Thomson, a renal nurse from Dunfermline, told the conference how she had managed to get her whole unit to save large amounts of waste by making fairly simple changes. “Champions” are important, everybody agreed, and maybe “metrics” and reputation might be the key to get some to act.

Some of those who have been beating the environmental drum for many years think, however, that messages are unlikely ever to be enough and that some sort of regulation is required. If, for example, every individual and organisation had a carbon entitlement that couldn’t be breached then they would have to change.

But taking such a step will depend on the public being willing, which brings us back to messages that might lead people to demand action. The sad truth is that it will probably require a “non-linear event,” a massive loss of probably Western life from a storm, flood, or heatwave – or something we haven’t though of at all – to create that demand for action. We may not have long to wait.

Richard Smith was the editor of the BMJ until 2004 and is director of the United Health Group’s chronic disease initiative.