We have allowed ourselves to become slaves to speed, which demands the consumption of non-renewable sources of energy.

Yet we largely ignore one inexhaustible and abundant resource, the wind.

There was a time when it was unthinkable to move goods from Melbourne to Sydney or Brisbane by road.

They were sent by sea, propelled by wind.

Sailing ships bore passengers and freight across the world.

We could return to the seaways much of the traffic now using our highways and airways.

The design and development of a range of suitable craft should be already on the drawing-boards of nautical architects.

Much of our rushing about from place to place to do business is quite unnecessary in this age of advanced telecommunications technology.

With almost every home and business in the developed world on the internet, face-to-face discussion can be conducted electronically, cutting out those inter-city trips so beloved of the politicians and public servants, saving time and energy.

We indulge ourselves with sporting circuses requiring teams to fly weekly from this venue to that, leaving a trail of carbon in the skies between and within Australia, South Africa and New Zealand, to mention but one football code.

We used to be content to enjoy the competition of local teams within our metropolitan cities, without leaving any carbon footprint.

We cycled or walked to the grounds, or maybe took a tram.

We used to walk or cycle to school; a ride in a car was a rare treat only a minority had cars.

We were more healthy, the air was cleaner, and life no less happy.

These are just a few of the ways in which we can and must learn to adapt to inevitable change.

Basil Johnson, Weston

I used to think that I lived in a world of scientific and social progress, where invention, innovation, and clever development of new ideas and techniques ensured that we would all live better, and our children in turn better than we did.

Now I have lost that naive optimism.

Sometimes I feel we have regressed to the Middle Ages.

There are crazy religions proscribing normal human behaviours.

There are warlords galore with fanatical followers prepared to kill anyone they decide is their enemy.

There are growing shortages of basic foods that we thought had been overcome for all time by a green revolution.

There are people who want us to throw away all our advanced technology and abolish our energy sources, the very ones that have extended many life expectancies and opened up a world of travel freedom.

It goes on and on.

It is frightening, because it seems to be leading to a new and unpleasant world of shortages, of restrictions, of governments taking new and arbitrary power over citizens and businesses by taxing out of existence the energy sources such as coal and oil and the raw materials such as steel and aluminium that require energy to produce.

It is a picture of retreat from the successes that have made life better for so many, to a world of shortages, of power rationing, of higher taxes.

So far our world looks superficially OK. The engine hums, the tanks have fuel, all systems are working.

But there are people who are trying to bring our world down, for spurious reasons of their own.

If they win we can look forward to a new Dark Age.

Malcolm Miller, Lyneham