Hotting up
The sun is getting hotter. It is also incredibly old -- about 4,500 million years old! One day it will blow up but that won't be for another 4000 million yearsScientists (called astronomers or cosmologists) who study the sun and stars know this because they can look at millions of other 'suns' (the stars) and find out what's happened to the different types over billions of years or so. But the Earth's climate seems to be heating upIt's this heating up which scientists call 'global warming' or 'climate change much much faster than can be explained by the sun making more heat. And the reason seems to be you people and your machines.



Almost all machines use oil, gas or coal. All of them produce pollution -- you know, the smelly stuff that comes out of car exhaust pipes and factory chimneys, that sort of thing. Much of this is a gas you can't see called carbon dioxide. It's this gas which seems to be the main cause of the trouble.

	Opening Pandora's carbon box Pandora was a woman who figured in one of the Greek myths. In the myth, the gods gave her a mysterious box. They'd put something nasty in the box and told her never to open it. But she was overcome by curiosity and opened the box. Out flew horrible stuff like plagues, sorrow and misery. She tried in vain to shut the lid but it was too late: the horrors were free. It's a little like that with fossil fuels. For millions of years, the planet has been tucking away its carbon dioxide in the form of coal, oil and limestone. This natural sequestering  of carbon and burying it deep in the Earth's crust has kept the climate machine in balance. Too much carbon means global warming; too little means cooling. Humans have opened the planetary Pandora's carbon box and let out fossil fuels on a vast scale. Burning them releases the carbon they contained back into the air as carbon dioxide, CO2.

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