All living things are made of Carbon. Carbon is always on the move. In the atmosphere, Carbon is attached to oxygen in a gas called carbon dioxide. Plants use carbon dioxide and sunlight to make their own food and grow. The carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years. When humans burn fossil fuels, most of the carbon quickly enters the atmosphere as carbon dioxide. Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without greenhouse gases the earth would be frozen. Humans have burned so much fuel that there is about 30% more carbon dioxide in the air today than there was 150 years ago. This is also causing the Earth to become a warmer place. Ice core show us that there is more carbon dioxide in the air than there has been the past 420,000 years.

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