Too often we take for granted the very finely balanced system that gives us life on this wonderful planet.

Not only is the temperature just right, with enough water for most of us, but the chemical balance of the atmosphere provides us with the appropriate amount of oxygen for our lungs, and carbon and nitrogen for our plants.

Not too much, not too little, but just right, and we should aim to keep it that way. We certainly live on the Goldilocks planet, and yet it could so easily all be different.

Let me tell you a story about a great flood that maybe has become a folk memory across the world.

About 8,200 years ago, in 6,200 BC, an event occurred that led to the temperature of the planet falling by about three degrees for a century or two. It was one of the final spasms at the end of the Ice Age, and early on in the interglacial period that has allowed humans to develop and flourish.

By then, most of the very large, mile-thick ice sheet that had covered much of North America melted, and a remarkably large puddle was left in the hollow caused by the weight of the ice. This Lake Agassiz was enormous, larger in area than all the present Great Lakes put together, and with more water than all the lakes that exist in the world today.

It drained away, particularly into the North Atlantic, where it blocked the warming currents from the south, the Gulf Stream, and altered the weather systems above it.

These changes stimulated the beginnings of agriculture in the Middle East, and the few metres that sea level rose may be the origins of the flood folklore that exists in many parts of the world.

The point of all this is that it doesn’t take much to disturb the fine balance that we have adjusted to over the years, with consequences that may be difficult to anticipate.

Very recent experiences of cold winters in Western Europe, and in North America, may be related to changes in the high altitude jet stream because of the rapidly melting Arctic ice.

The world has coped with very slow changes over thousands of years in the past, but the impact of human activity on the natural balance is now so intense that changes are likely within periods of a few generations, and certainly within centuries.

The last million years tell us that serious changes take place even without our help. We really should take note of the fragile balance in our beautiful world, and that means making sure we don’t disturb the climate.

So no more CO2, please.