Long, long ago when the world was new, life of any kind was impossible. The air was full of carbon dioxide and it had no oxygen at all. It stayed that way for two billion years.
Then an extraordinary thing happened. It was the sort of thing that could only happen once in a billion years or so. Somewhere in that great soup of chemicals forming, disintegrating and reforming, something came together in such a way that it was able to reproduce itself. It was blue-green algae. These algae were able to grow, and as they grew they gave off oxygen.
Now some tiny sea plants could grow. They took in carbon dioxide from the air, held onto the carbon and gave off more oxygen.
Over the next billion years, more and more plants were able to grow, and eventually some sea creatures appeared. When they died their skeletons fell to the sea bed, taking the carbon in them with them.
So gradually, while the air filled up with oxygen, it held less and less carbon dioxide. Later, when plants died they fell into the earth and got compressed into coal and oil, locking in even more carbon. Eventually, there was only a tiny amount of carbon dioxide left in the air, which was just the right amount for plants and animals to flourish.
Over the next billion years the world, and the plants and animals in it, gradually adjusted to each other, and for many millions of years after that, they lived in harmony with the environment. During the day plants took in carbon dioxide and gave out oxygen. At night, they did the opposite, and so did animals. And when things died, they gave out carbon dioxide too. In this way, everything balanced perfectly.
And then came humans. Humans were not content just to live in harmony with their environment. They wanted more, and as they were very clever they soon learned how to get it. At first they caused no trouble. They killed a lot of animals and caused some to go extinct, and they burned wood-fires, but these things didn’t upset the environment very much. The carbon released from burning wood was soon trapped again by living plants. Dead wood released carbon dioxide anyway.
But then humans became too clever for their own good. They invented machines to make life easier for themselves, and to make nice things. They became greedy and lazy, and they wanted more and more nice things, and more and more machines to make life easy.
These machines needed energy. At first they used the power of nature. They invented windmills and water wheels and used horses to travel. But the humans wanted bigger and better machines and they needed more energy. Then someone found the coal and oil in the ground, and they discovered that burning them gave a huge amount of energy.
With all this wonderful coal and oil, humans could make even more and even bigger machines to give themselves more and more nice things. They invented trains and cars and aeroplanes and spaceships. And they could heat their houses with coal and oil too. And the more humans realised they could have, the more they wanted, the more they gave themselves, and the more coal and oil they burned to get these things.
But there was a problem with coal and oil. The carbon inside them had been trapped down in the ground for 300 million years and it was not part of the natural carbon- oxygen cycle that life had evolved to depend on. Now a whole lot more carbon was being pumped into the air and it was upsetting the balance.
Scientists explained it to the other humans. The extra carbon dioxide was trapping the sun’s heat and warming up the world. It would melt ice and cause the sea-level to rise. There would be floods. And it would change the weather. Some places would get much hotter weather, some places would get colder. The rain would fall much more heavily sometimes, and sometimes there would be long dry spells. It would be more difficult to grow food. And if they didn’t stop burning coal and oil it would get worse and worse. The scientists also told them they should stop breeding cattle too, because they pumped out methane which was an even worse greenhouse gas than carbon dioxide.
At first, the humans wouldn’t believe this. ‘You can’t prove it,’ they told the scientists. It’s not true,’ some of them even said, if one day happened to be cold.
‘I’m not giving up my lifestyle, unless everybody else does,’ many of the humans said.
So they carried on enjoying themselves, driving around in big cars, flying thousands of miles in aeroplanes, buying things and heating their houses, all of which burned lots of coal and oil. They kept all their cows, too. And the problem got worse and worse.
But soon they saw the effects. Some places got very fierce heat-waves and thousands of humans died. Some places got droughts and they ran out of water. Other places got too much rain and they flooded. More and more places got hurricanes which blew houses away.
And eventually the humans realised that they would have to do something about it, or the world would be in an even worse state when their children grew up. They would have to stop burning coal and oil. They would have to stop driving big cars and flying all over the world in aeroplanes. They would have to stop buying things they didn’t need. They would have to find other ways of making energy, and ways of using less energy. And they would have to stop eating beef.
And they did. They gave up driving everywhere in cars and started walking or cycling. Or they took the bus instead. They stopped flying great distances in aeroplanes and took their holidays closer to home, and when they wanted to speak to other humans far away they phoned or emailed, instead of visiting. They stopped eating beef and kept only a very few cows.
They all worked together on this great challenge. They helped one another to insulate all their houses. They put off-shore windmills all round the coast. They put solar panels on everybody’s roof. And they fed whatever extra energy they made into the electricity grid. They covered huge fields and deserts with solar panels. They tapped into the heat deep underground. And they used all this new clean energy instead of coal and oil.
At first all these efforts didn’t seem to do any good. The problems with the weather didn’t go away. The humans began to think their work was all for nothing. But the scientists reminded people that they had to be patient. And so they carried on.
Then one day, the scientists declared that the amount of carbon in the atmosphere had gone back to normal and that they could hope the climate problems would go away. The humans waited and waited. They waited a very long time, and there were still lots of problems with the weather. ‘But at least it isn’t getting any worse,’ they said to one another.
Then after some years, the humans started noticing that they hadn’t had any severe hot spells, or long, long droughts, or disastrous hurricanes for a long time.
‘Perhaps we’ve fixed the climate problem, then,’ some said.
‘Perhaps we have,’ replied others.
And everyone smiled in relief and hugged one another. They felt so proud. They had worried they would be leaving their children with a damaged world, but now they dared to hope that they had fixed it, after all.
And the humans noticed that their new environment was cleaner, quieter and safer than it had been for a long time, and they liked it very much and wanted to keep it that way. And so they did.
The humans had been confronted with an enormous problem but they had faced up to it and solve it. It went down in history as The Great Climate Change Challenge of the 21st Century. It reminded their descendants of the catastrophe that nearly happened. And so they remembered to live in harmony with their environment, and for as long as they did, humans survived and thrived.