It seems very radical to many people to say we must de-carbonise our energy supply by 2050, to save the atmosphere. However, it may be useful to look back at how much things have changed over the last 50 years.

I used to go to my granny’s house in the 1950s, on a steam train, powered by lumps of coal. Her lighting and cooking were by town gas, made from coal, as was the electricity that powered the trams and trolley buses.

There were real winters then, that will never be seen again – with one that allowed us to enjoy snowballing from Boxing day through into March. Fogs were normal for half the year, until a lot of people died of bronchitis and they passed the Clean Air Act, making smoky fuel illegal in towns, with a dramatic effect on air quality (and visibility).

Someone then called at every house to convert our appliances to North Sea gas (no individual choice). Central heating replaced open fires. Britain became an oil-rich state, and we soon forgot the 1973 oil price shock from the Arabs. Trams and half the train network were closed. Car ownership soared and bicycles were forced off the roads.

But North Sea oil and gas have peaked in 30 years, so these fuels are now increasingly imported from distant countries. The coal mines closed. No new nuclear stations have been built for decades and the oldest are closing (before we have worked out what to do with their wastes.)

While we ran through all these energy sources, we ignored insulation and efficiency, so the scope to use less must now be huge. Microelectronic chips have been developed that can control all appliances. The North Atlantic brings these islands more wind, wave, tidal and hydro power than we can use. Windmill Hills and Mill Streams across the land wait to be re-discovered.

So, can we completely change our energy system in 40 years ? I say that we have in the past, we can again, and really have no alternative. “Unsustainable” means exactly what it says.

John Newson