Carbon cycle and climate change / global warming
Carbon is the building block of life. It is the basic element of all organic substances, from fossil fuel to DNA. Most of the Earth’s carbon—about 65,500 billion metric tons—is stored in rocks. The rest is in the ocean, atmosphere, plants, soil and fossil fuels. Carbon can move from one of these realms to another as a part of the carbon cycle. Over the long term, the carbon cycle seems to maintain a balance that helps keep Earth’s temperature relatively stable. Today, human activities,such as burning fossil fuels and clearing forests (that store carbon) have brought changes to the carbon cycle by emitting huge amounts of carbon into the atmosphere that cause an increase in global temperatures.