In the good old days, a couple of centuries ago, life must have been almost unbearable, being very smelly and unhealthy, and it was probably a blessing that it was so short. Folk in the growing cities disposed of their bodily waste by throwing it into the street to be collected by the night-soil man. What a job!

At that time any significant change was considered impossible because of opposition from landlords, weak local governance and the night-soil men themselves. Yet a century or so later the decisions were taken, perhaps driven by individuals who made real progress in understanding that dirty water was the real reason for typhoid and cholera.

Even so, despite the fact that there was an increasing awareness that a better system was technically possible and expanding suburbs could start from scratch, it took thousands of deaths and more than 100 years for toilets, piped water and sewage systems to catch on.

It doesn’t have to be that slow, as it is possible to change very quickly in the face of an overwhelming threat, as the Second World War showed. When finally provoked, the United States managed to roll out tanks, aeroplanes and ships instead of Buicks and Cadillacs within months of Pearl Harbour.

A smaller but no-less dramatic intervention was our reaction to the foot-and-mouth outbreak a decade or so ago. We didn’t hesitate to kill millions of cattle, close off large areas of the countryside and ruin the livelihood of many rural communities.

It’s clear that we humans can make serious and immediate changes to the way we behave and are organised if the danger is considered real and immediate. Such events as epidemics and enemy attacks are reasonably clear-cut, threaten our current lives, and are caused by organisms or other nations, rather than ourselves. We see ourselves as victims and so are prepared to take action to overcome the problem.

However, it’s a different matter when the threat is global rather than regional as it loses its personal identity, particularly if it’s not immediate and won’t become really obvious until a couple of generations later. Above all, when we are all involved there is no-one else to blame and we are reluctant to accept our responsibility.

This partly explains our attitude to climate change, despite the enormous threats to life, health and food sources that our grandchildren will face before they die. It is global, takes years rather than months, and is caused by every one of us whenever we produce carbon dioxide or methane.

It’s not helped, either, by the modern night-soil men – the oil and coal companies.